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The histology of basaloid squamous cell carcinoma (BSCC) can resemble that of adenoid cystic carcinoma (AdCC). Herein, we report two cases of BSCC with adenoid cystic-like features (BSCC-AdC). We collected cases of AdCC and BSCC of the head and neck region, extracted two cases with unusual histology, and reexamined them histologically and immunohistochemically. Case 1 involved an 81-year-old Japanese male, who had an elastic-hard mass on the left side of his tongue, and a biopsy examination suggested AdCC. Case 2 involved a 63-year-old Japanese male, who had a polypoid mass on his right hypopharynx. He was diagnosed with AdCC with high-grade transformation. Histologically, atypical cells in a myxoid stroma, which exhibited trabecular, nest-like, and/or cribriform growth patterns, and necrosis were observed in both cases. Case 2 displayed more marked cellular atypia than Case 1. Immunohistochemically, the tumor cells were diffusely positive for cytokeratin 5/6, p63/p40, SRY-related HMG-box 10 and Ki-67, but negative for other myoepithelial markers and p16. Finally, both cases were rediagnosed as BSCC-AdC. It is known that esophageal BSCC displays adenoid cystic-like features, and BSCC-AdC also sometimes occurs in the head and neck region. Clinicians should carefully differentiate BSCC-AdC from AdCC of the minor salivary glands and human papillomavirus-related carcinoma.

Sinonasal renal cell-like adenocarcinoma (SRCLA), which is an extremely rare but established entity, belongs to the non-salivary gland type of low-grade adenocarcinomas arising from the sinonasal tract. We report a case of high-grade SRCLA. The patient was a 63-year-old Japanese male, who complained of nasal obstruction. Histologically, the tumor exhibited solid nests and sheet-like structures composed of atypical clear or eosinophilic cells with central necrosis. The tumor cells contained periodic acid Schiff-positive glycogen. Immunohistochemically, they were positive for cytokeratin (CK)7, CD10, carbonic anhydrase (CA)-IX, the epidermal growth factor receptor (EGFR), mucin 1, and cancer antigen 125, whereas they were negative for CK20, caudal type homeobox 2, CK5/6, p40, vimentin, S-100, a renal cell carcinoma marker, paired box gene 8, and the human epidermal growth factor receptor 2. Both local recurrence and late lymph node metastases arose in this case. Therefore, the tumor was considered to be clinically aggressive and was diagnosed as a high-grade SRCLA. Immunostaining of CD10 and CA-IX was very diagnostically useful. Although 14 cases of SRCLA have been reported previously, all of them involved low-grade malignancies, and no descriptions of their EGFR statuses were provided. This is the first report about a high-grade SRCLA exhibiting EGFR overexpression.

Recently the author encountered a peculiar tumour of the bladder consisting of the following three components: MALT lymphoma, scattered poorly cohesive sarcomatoid urothelial carcinoma within MALT lymphoma, and surface non-invasive, low-grade conventional urothelial carcinoma (UC) occurring in a 65-year-old female. A low-power view showed MALT. Meticulous observations revealed a small amount of non-invasive, low-grade conventional UC at the surface area. In addition, meticulous observations identified a small number of cytokeratin-positive, poorly cohesive sarcomatoid UC cells scattered within the MALT lymphoma. The MALT lymphoma was typical. Immunohistochemically, the scattered sarcomatoid cells within the MALT lymphoma were positive for various types of CK, EMA, p53 and Ki-67 (LI = 70%). The MALT lymphoma was composed mainly of B-cells (CD10, CD20, CD23, CD79α, κ-chains and λ-chain), but T-cells positive for CD3, CD4, CD5, CD43 or CD45RO were seen in a very small number. This scattering sarcomatoid UC within MALT lymphoma of bladder has not been reported.

Molecular mechanisms of human ductal plate (DP) development and differentiation (DD) are unclear. The author immunohistochemically investigated expressions of cholangiocellular antigens (CEA, CA19-9, EMA, MUC1, MUC2, MUC5AC, MUC6, mucins, CK7, and CK19), hepatocellular antigens (HepPar1, AFP, CK8, and CK18), hepatic stellate/progenitor cell (HSC) antigens or stem cell (SC) antigens (C-erbB2, CD56, chromogranin, synaptophysin, bcl2, NSE, NCAM, KIT, and PDGFRA), and proliferating antigen (Ki67) in 32 human fetal livers (HFL). The DD of human intrahepatic bile duct (IBD) could be categorized into four stages: DP, remodeling DP, remodeled DP, and immature IBD. All the molecules examined were expressed in the DP and DP derivatives. These results suggest that human DP or DP derivatives have capacities to differentiate into cholangiocellular, hepatocellular, HSC, SC, and neuroendocrine lineages. The data also suggest that NCAM, KIT/SC factor-signaling, NSE, HGF/MET signaling, PDGFa/PDGFRA signaling, chromogranin, synaptophysin, and CD56 play important roles in DD of DP and biliary cells of HFL. DP, DP derivatives, and IBD in HFL have proliferative capacity.

The recent recognition of concept of perivascular myoid cell (PMC) phenotype and perivascular epithelioid cell (PEC) phenotype has changed the concept of angiogenic tumors, in particular "hemangioperycytoma" (HPC)-like tumors. The PMC concept has yielded myopericytoma, myofibroma, myofibromatosis, angioleiomyoma, and glomus tumors, while the PEC concept that shows melanocytic lineage has given rise to PEComa, clear cell sugar tumors, angiomyolipoma, and lymphangiomyomatosis. Here, the author reports a case of myopericytoma of soft tissue (thigh) occurring in a 47-year-old man. The patient had noticed the thigh tumor 4years before, and was admitted. The tumor was located in subcutaneous tissue, was encapsulated, and measured 4×3×3cm. Total excision was performed. Grossly, the tumor is a soft reddish encapsulated tumor with very well demarcation. Histologically, the tumor showed typical HPC-like features with focal nodular proliferation of HPC-like tumor cells. Immunohistochemically, the vasculatures were positive for vimentin, CD31, CD34, and factor VIII-related antigen. In contrast, the HPC-like tumor cells were positive for vimentin, α-smooth muscle antigen, h-caldesmon, bcl-2, and factor XIIIa, but negative for cytokeratins, desmin, CD31, CD34, factor VIII-related antigen, S100 protein, melanosome, CD99, and KIT. Ki-67 labeling was 15%, and p53 was mildly positive. The overall features were those of myopericytoma. The patient is now alive without recurrence 5years after the operation. A brief literature review and differential diagnosis were made.

Herein reported is an extremely rare case of primary MALT lymphoma of cerebral parenchyma. A 79-year-old man presented with paresis. Imaging modalities identified a tumor measuring 3cm in diameter in right cerebral parenchyma. An operation completely resected the tumor. Macroscopically, the tumor was well defined, but showed mild infiltrative features. Histologically, the tumor showed proliferation of small atypical lymphocytes separated by fibrous septae with AL amyloid depositions. No apparent plasma cell differentiation was seen. The tumor cells showed monotonous appearances with hyperchromatic nuclei but without nucleoli and nuclear indentations. Immunoblastic cells were scattered. Immunohistochemically, tumor cells were positive for vimentin, CD45, CD20, CD79α, bcl-2, CD3 (focal), CD45RO (focal), CD5 (focal), CD10, CD23, bcl-6, CD138, p53, and Ki-67 (labeling=27%). The immunoblastic cells were positive for CD30. The lymphoid cells were negative for Epstein–Barr virus (EBV)-related molecules of EBV latent membrane protein-1 (LMP-1) and EBV early RNAs (EBER). They were also negative for cytokeratins AE 1/3 and CAM5.2, cyclin D1, CD34, GFAP, α-smooth muscle actin, and S100 protein. Because of the heterogeneity of tumor cells and positive AL amyloid deposition, the author diagnosed it as primary MALT lymphoma. The patient is now free from tumors. Differential diagnosis was discussed.

Epithelioid sarcoma (ES) usually occurs in extremities. ES shows characteristic granulomatous morphologies, and its prognosis is not so poor. Proximal-type ES (PT-ES) is a variant of ES, and is characterized by central locations, severe atypical features, and poor prognosis. Both ES and PT-ES histologically show epithelial and sarcomatous patterns, and immunohistochemically express both vimentin and cytokeratins. A 77-year-old man presented with sore throat. The laryngoscope revealed a large polypoid tumor (4×3×4cm) in upper pharynx, and a large biopsy was taken. The biopsy showed malignant epithelioid and spindle tumor cells. There were no apparent transitions between normal epithelial cells and tumor cells. The tumor consisted of malignant epithelioid and spindle cells with marked anaplasia. The tumor showed marked infiltrative features and lymphovascular permiations. Mitotic figures, atypical mitosis, and necrotic areas were present. No apparent features of sarcomas were seen. No rhabdoid cells were seen. Immunohistochemically, the malignant cells were positive for vimentin (3+, diffuse), CK AE1/3 (1+, focal), CK CAM5.2 (1+, diffuse), CK8 (1+, focal), CK18 (1+, focal), CD20 (1+, focal), p53 (3+, 84%), Ki-67 (labeling=94%), CD68 (2+, only focal), and anti-trypsin (2+, only focal). They were negative for CK34BE12, CK5, CK6, CK7, CK14, CK19, CD99, CEA, CA19-9, CA125, EMA, S100 protein, NCAM, NSE, synaptophysin, chromogranin, α-smooth muscle actin, smooth muscle actin, desmin, CD34, CD31, CD45, D2-40, factor-VIII-related antigen, HMB-45, Melan-A, myoglobin, MDM2, CDK4, KIT, and PDGFRA. The author diagnosed this pharyngeal tumor as PT-ES, but the author cannot completely exclude the possibility of sarcomatoid carcinoma. The prognosis of patient was poor; the patient died of carcinomatosis 2years after the manifestation.

Primary mucinous adenocarcinoma (MA) of vermiform appendix is extremely rare; only three cases have been reported in the English literature. A 77-year-old man presented with abdominal pain, and was diagnosed with acute appendicitis. Appendectomy was performed. The resected appendix showed submucosal swelling measuring 0.7×0.6×0.6cm in the tip of appendix. The appendix showed inflammation and numerous diverticuloses. Microscopically, the submucosal swelling was a mucin lake in which adenocarcinoma cells were floating. The adenocarcinoma cells were MA in 80% and signet-ring cell carcinoma in 20%. The carcinoma cells were located in the submucosa, muscular layer and subserosa, sparing the mucosa. No apparent lymphovascular permeation was seen. The surgical margins were negative for tumor cells. The non-tumorous appendix shows numerous diverticulosis, diverticulitis, and appendicitis. Immunohistochemically, the tumor cells were positive for CK CAM5.2, CK AE1/3, CK8, CK18, CK19, CK20, EMA, CEA, CA19-9, MUC1, MUC2, MUC5AC, MUC6, NCAM, p53 and Ki-67 (labeling index=23%). The tumor cells were negative for CK34BE12, CD5, CK6, CK7, NSE, chromogranin, synaptophysin, CA125, KIT, and PDGFRA. No metastasis has been seen 2.5years after the operation.

Using a computer database, the author investigated the histopathology of 10 000 consecutive gastric specimens, taken in the last 12 years (2002–2013) at the pathology laboratory of a Japanese hospital. Re-observation of the already examined histological sections was done when the histological diagnosis and findings on the computer data base were not very obvious. The gastric specimens were identified as 8579 benign conditions and 1421 malignant lesions. The 8579 benign conditions were comprised almost normal stomach in 74 cases (0.9%), chronic gastritis in 4374 (51.0%), benign gastric peptic ulcer in 2195 (25.6%), foveolar hyperplastic polyp in 1004 (11.7%), fundic gland polyp in 421 (4.9%), adenoma in 487 (5.6%), heterotopic pancreas in 9 (0.1%), pancreatic acinar metaplasia (PAM) in 8 (0.1%), and amyloidosis in 7 (0.1%). Chronic gastritis showed lymphocytic infiltration and frequently showed erosions and intestinal metaplasia. Gastric peptic ulcer showed exudate, necrosis, active inflammation, and regenerative atypia of the epithelium. Foveolar hyperplastic polyp revealed 23 malignant changes and frequently showed dysplastic glands and intestinal metaplasia. Fundic gland polyp demonstrated cystic dilations of fundic gland ducts. Gastric adenoma showed adenomatous proliferation in the superficial mucosa and cystic dilation of the epithelium under the adenoma. Heterotopic pancreas was located in the submucosa and consisted of acinar cells, ducts, and occasionally islets. PAM was a tiny lesion in the mucosa and consisted of only pancreatic acinar cells. Amyloidosis was primary amyloidosis with positive reaction with Congo-red stain.

Primary lymphoma of soft tissue is very rare. A 59-year-old Japanese man presented left leg tumor measuring 3 × 3 × 2 cm without skin ulceration. A large incisional biopsy was performed. It showed atypical lymphoid cell proliferation in subcutaneous tissue next to the fascia. Immunohistochemically, the tumor cells were positive for CD45, CD20, CD79α, λ-chain, and p53 protein. The Ki-67 labeling was 100%. In contrast, they were negative for various types of cytokeratins, epithelial membrane antigen, CD3, CD30, CD10, CD45RO, TdT, κ-chain, CD56, bcl-2, bcl-6 and MUM1. A diagnosis of diffuse large B-cell lymphoma (DLBCL) of non-germinal center type (DLBCL-non-GC) of soft tissue was performed. Systemic investigation using various imaging modalities including CT, MRI and Ga-scintigraphy revealed lymph nodes swelling in the inguinal region. The patient was treated by R-CHOP chemotherapy and radiation. The tumor and lymph nodes were markedly reduced in size. He is now alive with disease two years after the first manifestation.

Mixed tumor of soft tissue is extremely rare; only 15 cases have been reported in English literature. A 56-year-old man presented with a tumor in right arm. Physical examination showed a tumor measuring 3 × 3 × 3 cm of deep portion of right arm. MRI showed a well-defined deep tumor measuring 3 × 3 × 4 cm of arm next to fascia. The tumor was resected, and it was found that the tumor is located in deep subcutaneous tissue outside the fascia. Histologically, the tumor was well-defined and contained a fibrous capsule. The tumor cells showed no significant nuclear atypia. The tumor was composed of epithelial, myoepithelial, and stromal elements. The epithelial element formed tubules, and myoepithelial element showed solid nests and periepithelial linings. The epithelial element showed frequent apocrine features including apocrine snouts. The stromal element was composed of cartilage and myxoid tissues. Immunohistochemically, the epithelial element was positive for cytokeratin (CK) AE1/3, CK CAM5.2, CK34BE12, CK7, CK8, CK18, CK19, EMA, CEA, CD56, p53, and Ki-67 (labeling = 80%), but negative for CK5/6, CK14, CK20, vimentin, p63, S100 protein, CD10, CD34, ASMA, CD68, myoglobin, bcl-2, BMP-2, TGF-β1, CDK-4, and MDM2. The myoepithelial element was positive for CK AE1/3, CK CAM5.2, CK34BE12, CK5/6, CK7, CK8, CK14, CK18, p63, vimentin, CD10, S100 protein, bcl-2, p53, and Ki-67 (labeling = 20%), but negative for CK19, CK20, EMA, CEA, CD34, ASMA, CD68, CD56, myoglobin, BMP-2, TGF-β1, CDK-4 and MDM2. The stromal element was positive for vimentin, S100 protein (cartilage), and Ki-67 (labeling = 6%), but negative for other antigens examined including bcl-2, BMP-2, TGF-β1, CDK-4 and MDM2. No findings of metastasis, invasion, and recurrence were recognized clinically. The author speculates that the current mixed tumor was derived from misplaced apocrine glands in the deep soft tissue.

The aim of the study was to investigate nerve fibers (NF) in human fetal livers. An immunohistochemical study was performed. NF were classified into portal tract innervation (PoI) and parenchymal innervation (PaI). The hilum area showed many Pol NF at 7 GW, and NF increased with gestational week (GW). Direct innervations to biliary epithelium were recognized. In large portal tracts, a few NCAM-positive mesenchymal cells were seen at 8 GW and many mesenchymal cells were noted around 12 GW. Apparent NF emerged around 15 GW, and NF increased with GW. Many NF plexuses were seen in 30-40 GW. In small portal tracts, no NF were seen in 7-10 GW. A few NCAM-positive mesenchymal cells emerged in 11 GW, and they increased thereafter. Apparent NF were seen around 20 GW and NF increased with GW. At term (40 GW), PoI NF were still immature. Ductal plate (DP) was positive for NCAM, NSE, chromogranin and synaptophysin, and direct innervations to DP were seen. The direct innervations to developing bile ducts and peribiliary glands were also seen. PaI NF were first seen at 21 GW and was consistent until 40 GW in which a few NF were seen in PaI. These observations suggest that PoI NF arise from committed portal mesenchyme. PaI NF are very immature at 40 GW. There are direct innervations to bile ducts, peribiliary glands, portal veins, hepatic arteries, and DP.

There are no studies on stem cells (SCs) and development and differentiation (DD) of the human adrenal glands. The SCs in DD of the adrenal glands were herein investigated histochemically and immunohistochemically in 18 human embryonic adrenal glands at gestational week (GW) 7–40. At 7 GW, the adrenal glands were present, and at 7 GW, numerous embryonic SCs (ESCs) are seen to create the adrenal cortex. The ESCs were composed exclusively of small cells with hyperchromatic nuclei without nucleoli. The ESCs were positive for neural cell adhesion molecule, KIT, neuron-specific enolase, platelet-derived growth factor receptor-α, synaptophysin, and MET. They were negative for other SC antigens, including chromogranin, ErbB2, and bcl-2. They were also negative for lineage antigens, including cytokeratin (CK)7, CK8, CK18, and CK19, carcinoembryonic antigen, carbohydrate antigen 19-9, epithelial membrane antigen, HepPar1, mucin core apoprotein (MUC)1, MUC2, MUC5AC, and MUC6, and cluster differentiation (CD)3, CD45, CD20, CD34, and CD31. The Ki-67 labeling index (LI) was high (Ki-67 LI = around 20%). α-Fetoprotein was positive in the ESCs and adrenal cells. The ESC was first seen in the periphery of the adrenal cortex at 7–10 GW. The ESC migrates into the inner part of the adrenal cortex. Huge islands of ESC were present near the adrenal, and they appeared to provide the ESC of the adrenal. At 16 GW, adrenal medulla appeared, and the adrenal ESCs were present in the periphery or the cortex, in the cortical parenchyma, corticomedullary junctions, and in the medulla. The adrenal essential architecture was established around 20 GW; however, there were still ESCs. At term, there are a few ESCs. These data suggest that the adrenal glands were created by ESCs. Microsc. Res. Tech., 78:59–64, 2015. © 2014 Wiley Periodicals, Inc.

Basaloid squamous cell carcinoma of esophagus (BSCC-E) is rare. This case report is the first demonstrating KIT protein expression of BSCC-E. A 74-year-old man presented with dysphagia. Endoscopy revealed a polypoid tumor (2×2×2.5cm) with a stalk in cervical esophagus. Biopsy showed squamous cell carcinoma with undifferentiated areas. An endoscopic submucosal dissection (ESD) was performed. Grossly, it was solid tumor with white cut surface. Histologically, the tumor was hypercellular carcinoma consisting of solid areas of island. The tumor cells were composed of basaloid malignant cells with hyperchromatic nuclei, scant cytoplasm, and basophilic cytoplasm. Many mitotic figures were recognized. Foci of comedonecrosis were scattered. Areas of squamous and glandular differentiations were scattered. Immunohistochemically, the tumor cells were positive for pancytokeratin (PCK) CAM5.2, PCK AE1/3, cytokeratin (CK) 7, KIT, CEA, CA19-9, EMA, Ki-67 (labeling index=80%). The tumor cells were negative for CK20, PDGFRA, NSE, vimentin, estrogen receptor, p53 protein, chromogranin, synaptophysin, CD56, and TTF-1.

Background: Nothing is known about huge clusters (HC) of embryonic stem cells (ESC) in human fetal organs (HFO). Aim: To know the status of HC-ESC in HFO. Methods: Morphology and immunohistochemistry (IHC) in 32 HFO of 7–40 gestational weeks (GW). Results: HC-ESC were seen in many HFO including central nervous system, spinal cords, spine, soft tissue, bone, skin, thyroid, lung, liver, pancreas, gall bladder, extrahepatic bile duct, adrenal, kidney, bladder, foregut, midgut, hindgut, female and male genital organs, and neurons. HC-ESC's were composed of two populations depending on constituting cells. One were large cells with ample acidophilic cytoplasms with vesicular nuclei and nucleoli. The other were small cells with scant cytoplasm with hyperchromatic nuclei without nucleoli, resembling lymphocytes. The HC-ESC were frequently showed neuronal differentiation. HC-ESC were positive for NCAM, synaptophysin, NSE, chromogranin, PDGFRA, AFP, ErbB2, bcl-2, KIT, MET. They were negative for CD45, CD3, CD20, EMA, CEA, CA19-9, cytokeratin (CK) 7, CK8, CK18, CK19, MUC1, MUC2, MUC5AC, and MUC6. The mean Ki-67 labeling index (LI) was 13% ± 7%. HC-ESC showed a little glycogen but lacked mucins. These HC-ESC were seen in 7–25 GW, and they were rarely seen in 26–40 GW. Conclusions: The morphology, IHC, and ontogeny of HC-ESC were described. Microsc. Res. Tech. 77:825–831, 2014. © 2014 Wiley Periodicals, Inc.

Background: The molecular mechanisms of ductal plate (DP) development and differentiation (DD) in human fetal livers (HFLs) are unclear. Materials and Methods: The author immunohistochemically investigated expressions of NCAM, KIT, KIT, PDGFRA, and neuroendocrine antigens in 32 HFLs. Results: The processes of human intrahepatic bile duct (IBD) DD could be categorized into four stages: DP, remodeling DP, remodeled DP, and mature IBD. NCAM was always expressed in DP and remodeling DP, but not in remodeled DP and mature IBD. The biliary elements were positive for cytokeratin (CK)7, 8, 18, and 19. The hepatoblasts were positive for CK8 and CD18, but negative for CK7 and CK19; however, periportal hepatoblasts showed biliary-type CKs (CK7 and CK19). NCAM was always expressed in DP and remodeling DP, but not in remodeled DP and mature IBD. KIT was occasionally (12/32 cases) expressed in DP and remodeling DP, but not in remodeled DP and mature IBD. NCAM expression was also seen in some hepatoblasts and hematopoietic cells and neurons. KIT was also expressed in some hepatoblasts, hematopoietic cells, and mast cells. MET and PDGFRA were strongly expressed in DP, remodeling DP, remodeled DP, and mature IBD. MET and PDGFRA were also strongly expressed in hepatoblasts and hematopoietic cells. MET and PDGFRA were not expressed in portal mesenchyme, portal veins, sinusoids, and hepatic veins. DP showed immunoreactive chromogranin, synaptophysin, neuron-specific enolase (NSE), and CD56. Expressions of chromogranin and CD56 were infrequently seen in remodeling DP. No expressions of these four neuroendocrine antigens were seen in remodeled DP and mature IBD. The nerve fibers were consistently positive for chromogranin, synaptophysin, NSE, and CD56 in the portal mesenchyme in the stages of remodeling DP, remodeled DP, and mature IBDs. Conclusions: The data suggest that NCAM, KIT/stem cell factor-signaling, NSE, hepatocyte growth factor/MET signaling, PDGFα/PDGFRA signaling, chromogranin, synaptophysin, and CD56 play important roles in DD of biliary cells of HFL. They also suggest that the DP cells having neuroendocrine molecules give rise to hepatic stem/progenitor cells. Microsc. Res. Tech. 77:814–824, 2014. © 2014 Wiley Periodicals, Inc.

Background: The fetal development of extrahepatic bile ducts (EBD) is unkown. Materials and Methods: Development of EBD was examined by immunohistochemistry in 16 fetuses of 7–40 gestational week (GW). Gall bladder (GB) was not investigated. Results: At seven GW, a hepato-pancreatic bud (HPB) was seen near the hepatic hilus. At eight GW, embryonic EBD, GB and pacreas developed from HPB. Portal veins (PV) and hepatic arteries (HAs) were present in EBD at eight GW. Liver parenchyma was already present in seven GW. At eight GW, EBD at porta hepatis (PH) was already established; PH EBD was derived from ductal plate (DP). The distal and middle EBD gradually develeped and took shape of EBD at nine GW. In PH, cystic and hepatic ducts developed from DP at eight GW. EBD developed further, accompanying many nerve fibers (NF) at PH and distal and middle EBD. Apparent PV and HA were seen around 12 GW. Around 20 GW, HA and capillaries proliferated, giving rise to peribiliary capillary plexus (PCP) in all parts of EBD. EBD grew gradually further, and around 30 GW extrahepatic peribiliary glands (EPG) emerged from EBD but not from cystic duct. Around 36 GW, exocrine pancreatic acinar cells emerged from remodeled DP at PH. At term (40 GW), EBD was established but was as yet immature. Numerous NF were present around EBD. Histochemically, EBD epithelium had no mucins at 7–12 GW but contained neutral and acidic mucins at 23–40 GW. EPG had abundant neutral and acidic mucins. Immunohistochemically, alpha-fetoprotein (AFP) was consistently positive in the epithelial and mesenychyma. The NF and muscles of HPB present at seven GW were positive for neural cell adhesion molecule (NCAM), neuron-specific enolase (NSE), platelet-derived growth factor receptor-α (PDGFRA), and KIT, but they disappeared in nine GW. Expressions of cytokeratin (CK) seven and CK19 in EBD and EPG were slight or none, while expression of CK8 was moderate, and that of CK18 was strong. NF were positive for NCAM, NSE, synaptophysin, and chromogranin, and PDGFRA. MUC1 and MUC6 apomucins were noted in EBD and EPG. EPG contained numerous endocrine cells positive for chromogranin, synaptophysin, NCAM and NSE. A few endocrine cells positive for these antigens were seen in EBD. Numeous KIT-positive stem cells (SC) were seen in PH, EBD, PV, HA, PCP, and EPG. NCAM-positive and bcl-2-positive SC were also located in these structures. Epithelial cells of EBD and EPG showed expressions of MET, PDGFRA, CA19-9, MUC1, MUC2, MUC6, KIT, bcl-2, and ErbB2. No expressions of HepPar1, carcinoembryonic antigen (CEA), and epithelial membrane antigen (EMA) were noted. Conclusions: Although the findings have limitatios because this study of humans are descriptive one, the present data suggest that the processes of the development and differentiation of EBD system may be associated with EBD SC, CK prolifes, SFC/KIT signaling, HGF/MET signaling, PDGRa/PDGFRA signaling, fibroblast growth factor/ErbB2 signaling, neuroendocrine lineage, NF differentiation, pancreatic aninar cell differentiation, PCP differentiation, MUC apomucins differentiation, and expressions of AFP and CA19-9. HepPar1, EMA and CEA were not involved in them. Microsc. Res. Tech. 77:832–840, 2014. © 2014 Wiley Periodicals, Inc.

The author herein reports a case of multiple verrucous carcinomas (VCs) of the left lower gingiva. A 78-year-old man was admitted to our hospital because of gingival tumor. A biopsy revealed severe dysplasia. Surgical resection was performed. Grossly, there were three verrucous lesions (25, 20, 10 mm) in the left lower gingiva. Histologically, 2 tumors (4, 2 mm) were found in addition to the grossly visible 3 tumors. All the 5 tumors were VCs. The tumors showed verrucous and papillary proliferation of squamous epithelium with little cellular atypia. No invasive features were recognized. The dermis showed lymphocytic infiltration. The surrounding mucosa showed many broad foci of squamous cell carcinoma in situ and severe dysplasia (high grade intraepithelial neoplasm). Gradual merges between the VCs and squamous cell carcinoma in situ or severe dysplasia were frequently recognized. Immunohistochemically, the VC tumor cells and squamous lesions were negative for human papilloma virus antigens. P53 protein was expressed in all the VCs and squamous epithelial lesions: it was accentuated in the basal and suprabasal cells of VC. Ki-67 antigen was also expressed in the 5 VCs and in the squamous lesion, and Ki-67 labeling index ranged from 8 to 16 % in VC and from 37 to 62 % in the squamous lesions. These data support the multicentric nature of VC and that the severe dysplasia–carcinoma in situ sequence have been proposed in the etiology of VC.

The author reports an extremely rare case of atypical carcinoid of the pleura expressing KIT. An 81-year-old Japanese man with emphysema was found to have a mass (3×3×2 cm) in the left parietal pleura by various imaging modalities. Video-assisted tumorectomy was performed, but could not excise it completely. Histologically, the tumor was composed of atypical cells arranged in trabecular, ribbon-like, and rosette patterns. Mitotic figures and necrosis were present. The tumor cells were argyrophil. Immunohistochemically, the tumor cells were positive for pancytokeratins, cytokeratin (CK) 18, chromogranin (focal), p53, KIT, and Ki67 (labeling=17%). In contrast, the tumor cells were negative for CK5/6, CK7, CK19, CK20, CK34βE12, epithelial membrane antigen, vimentin, S100-protein, α-smooth muscle actin, desmin, CEA, TTF-1, CDX-2, AFP, HepPar-1, synaptophysin, CD56, CA19-9, CD15, neuron specific enolase, serotonin, CD34, platelet-derived growth factor-α, calretinin, thrombomodulin, WT-1, B72.3, and D2-40. The pathologic diagnosis was atypical carcinoid of the pleura. The patient was examined by whole body computed tomography, magnetic resonance imaging, and positron emission tomography, but there were no tumors other than the pleural tumor. Endoscopic examinations including upper and lower gastrointestinal tract revealed no tumors. Therefore, the pleural tumor was thought to be primary. Ten months later, the patient developed metastatic lesions in the vertebular and femoral bones, and died of respiratory failure. Autopsy was not performed. To the best of the author's knowledge, there are no cases of primary carcinoid in the pleura in the English literature. This case is also interesting in that the atypical carcinoid expressed KIT.

Obvious neuroendocrine differentiation has not been reported in glomus tumor. The author herein reports a malignant glomus tumor of the foot showing obvious neuroendocrine differentiation. A 63-year-old woman presented with tumor of the left foot. The tumor was superficially seated, and located in the dermis. It was completely resected with wide margins. It measured 0.7 × 0.7 × 0.6 cm. Microscopically, the tumor was composed of atypical epithelioid cells located around blood vessel-like structures. The epithelioid cells showed relatively clear cytoplasm and severe cellular atypia, and resembled basal cell carcinoma. Focal areas of squamoid differentiation, carcinoid patterns, and neural differentiations were seen. There was no necrosis or atypical mitosis. However, mitotic figures were seen in 16 per 50 high-power-fields (HPF). The hematoxylin and eosin (HE) diagnosis was basosquamous carcinoma. Immunohistochemically, the tumor cells were strongly positive for vimentin, -smooth muscle actin, and neuron-specific enolase. The tumor was focally positive for NCAM, synaptophysin and chromogranin. The blood vessel-like structures had a layer of CD31- and CD34-positive endothelial cells. Tp53 was positive and the Ki-67 labeling index was 23%. The tumor cells were negative for cytokeratin (CK) AE1/3, CK CAM5.2, CK5, CK6, CK7, CK8, CK14, CK18, CK19, CK20, p63, EMA, CEA, CA19-9, desmin, myoglobin, HMB-45, Melan-A, S100 protein, MUC1, MUC2, MUC5AC, and MUC6. Taken together with HE histology, the tumor was labeled as malignant glomus tumor with neuronal differentiation, based on the classification system of Folpe et al. The post-pathological diagnosis whole body examination using CT, MRI, PET, and endoscopies identified no tumors. The patient is now free from tumor and healthy 18 months after the resection.

Mesenchymal tumors (MT) of the gastrointestinal (GI) tract are relatively common conditions, the majority being gastrointestinal stromal tumors (GIST) [1–4]. The classification system of MTof the GI tract changed around 2000 when gain-offunction mutations of KIT and PDGFRA were for the first time found [1, 2]. Since then, the classification procedure of MTof the GI tract has been performed by immunohistochemical (IHC) findings of KIT, CD34, S100 protein, and myogenic proteins [3]. Therefore, studies of MTof the GI tract before around 2006 lost their significance. Schwannoma and leiomyoma of the colon are relatively rare, and circa 90 cases and circa 200 cases have been reported in the world literature, respectively. Since the diagnostic criteria of GIST and some MT were established only recently around 2006 [3], the incidence/prevalence of MT in the GI tract has not been evaluated and therefore unknown; a PubMed search revealed no such studies. Non-GIST MT appears very rare.

patient is now well free from tumors 3 months after the operation. Immunohistochemically, the epithelial cells were positive for pan-cytokeratin (CK) AE1/AE3, while myoepithelial and stromal cells were negative (Fig. 2a). The myoepithelial cells were clearly identified by immunostains for CK14 (Fig. 2b), p63 (Fig. 2c), and CD10 (Fig. 2d) [1–4]. Some of them were positive for S100 protein (Fig. 2e). CK CAM5.2, CK34BE12, CK5/6, CK7, CK8, CK18, and CK19 labeled both epithelial and myoepithelial cells. EMA and smooth muscle actin were negative in any cell types. Vimentin was positive in myoepithelial and stromal cells but not in epithelial cells. CEA, NSE, CD68, MUC1, MUC2, MUC5AC, and MUC6 were negative in any cell types of the tumor. TP53 was negative, and Ki-67 labeling index was 0.7 %. The present tumor is no doubt PA. Carcinoma ex PA, which means a carcinoma (mostly squamous cell carcinoma) arising from PA, was not seen. The histological features were typical for PA. The epithelial/myoepithelial nature of the present tumor is obvious by immunohistochemistry [1–4]. The negative p53 and very low Ki-67 index are almost confirmative for benign nature. Because no reported cases of PA of spermatic cord are seen in English literature (PubMed), the diagnosis was extremely carefully made with suspicion for malignant potential and with outer consultation. Since myoepithelial cells are free from spermatic cord, which is composed of urothelium, stromal cells, vasculatures, nerves, ganglion cells, and smooth muscle cells, the histogenesis of the present PA of spermatic cord is enigma but possibly represents myoepithelial differentiation of urothelium. In summary, the author reported the first case of PA in spermatic cord. Editor

[1] Shear wave splitting from local intermediate-depth earthquakes is investigated to detect the anisotropic structure in the mantle wedge beneath the South Kyushu area, Japan. We observed shear wave splitting with NEE-SWW to NWW-SEE polarization directions and delay times of 0.04–0.63 s. Trench-normal shear wave polarization anisotropy with a delay time greater than 0.3 s probably overlaps in the high VP/VS region at a depth of 100–150 km beneath the volcanic front. Model calculations for the cause of the anisotropy suggest that the development of “C-type” olivine crystallographic preferred orientation (CPO) with a trench-parallel b axis concentration and a trench-normal a axis concentration best reproduces observations compared to A-, B-, or E-type olivine CPOs and antigorite CPO. We conclude that a thick anisotropic layer, approximately 50 km, is formed by concentration of interstitial fluid in peridotite. We briefly discuss the mechanism carrying water to the deep mantle wedge. A possible explanation is that interstitial fluids in the mantle wedge are effectively released because of a decrease in dihedral angles of olivine-fluid interfaces at 150 km depth. Our results imply a close relation between the high density of explosive volcanoes in the South Kyushu area and the underlying water-rich mantle.

Clear cell adenocarcinoma of the urinary bladder is rare. A 73-year-old woman presented with chronic renal and cardiac failure. Blood tests showed elevated carcinoembryonic antigen and CA19-9 levels. Imaging techniques showed bilateral hydronephrosis and hydroureter. Cystoscopy showed a bladder tumor, and the biopsy showed malignant cells. The patient died 4 months later. Autopsy showed an elevated tumor of the bladder. Metastases to the liver, lungs, adrenal glands, spleen and bones were observed. The kidney showed chronic active pyelonephritis with hydronephrosis. The cause of death was chronic renal and cardiac failure and/or carcinomatosis. Histologically, the bladder tumor consisted of malignant clear cells arranged in solid nests and tubules. Histochemical stains for glycogen and mucins were negative. Metastases also showed similar histology. Immunohistochemically, the tumor cells were positive for carcinoembryonic antigen, CA19-9, CA125, CD10, pancytokeratins (AE1/3, CAM5.2), cytokeratin (CK) 34βE12, CK7, CK8, CK18, CK19, EMA, MUC1, p53, and Ki-67 (labeling=40%). They were negative for CK5/6, CK14, CK20, estrogen receptor, progesterone receptor, α-methylacyl-CoA-racemase, p63, CDX2, MUC2, MUC5AC, MUC6, CD45, CD34, vimentin, neuron-specific enolase, S100 protein, desmin, HMB45, AFP, α-smooth muscle actin, MDM2, HER2/neu, synaptophysin, and CD56. Metastases showed the same immunohistochemical findings.

Intradermal nevocelluar nevus is a very common hamartomatous neoplasm of the skin. The author herein reports two tumors of intradermal nevocelluar nevus in the neck occurring in a 55-year-old woman. The tumors were characterized histologically by typical intradermal nevocelluar nevus with significant areas of adenoid or glandular formations. In both tumors, hair follicles were seen in centers of the tumors. The cellular features of the adenoid areas were the same as those of solid areas. In solid areas, vague vacuolated and obvious vacuolated cells were recognized in some areas. In solid areas of the surface and lateral areas of the tumors also showed clear cut adenoid features without vacuolations. The adenoid features showed mild depositions of hemosiderins. There were gradual merges between solid areas and adenoid or glandular areas. Histochemically, the tumor cells including adenoid structures had glycogen, but had no mucins. Immunohistochemically, cells of both tumors were strongly positive for S100 protein, vimentin, NSE, NCAM, and bcl-2, and were weakly positive for synaptophysin and chromogranin. The tumor cells showed low cell proliferative potential; the Ki-67 labeling index was 2%. The tumor cells including adenoid structures were negative for CK AE1/3, CK CAM5.2, desmin, smooth muscle actin, HMB45, p53, p63, CD31, laminin, type 4 collagen, CEA. CD34, CA125, CA19-9, CD45, GFAP, KIT, PDGFRA, CD68, estrogen receptor, progesterone receptor, EMA, MUC1, MUC2, MUC5AC, and MUC6. These histological, histochemical, and immunohistocheimical findings strongly suggested that the present two tumors with adenoid structures belong to intradermal nevocelluar nevus. The formation of the adenoid architectures in the intradermal nevocelluar nevus was discussed. Possible mechanisms appear loss of cell adhesions molecules. The adenoid structures seem not to be degenerative ones. Pathologists should be aware that intradermal nevocelluar nevus may show adenoid structures to avoid diagnostic confusions, for example adenoma and adenocarcinoma of skin appendages. The occurrence of this hitherto undescribed condition in two intradermal nevocelluar nevus in a patient may imply genetic lineage. To elucidate the mechanisms of adenoid structures in intradermal nevocelluar nevus seems future work.

In 2002, Seibel et al. presented a case series of 18 patients with villous adenomas of the urethra. Since then, only a couple of reports regarding this rare entity have been published. Recently (2013), Kao and Epstein proposed a new entity of tubular adenoma (4 cases) in the urinary tract, being similar to tubular adenomas in gastrointestinal (GI) tract; no following cases have been reported. Herein presented a case of tubule-villous adenoma (TVA) in the prostatic urethra (PU) of a 77-year-old man male patient suffering from dysuria. Cystscopy showed a polypoid/villous tumor of the PU, and transurethral resection of this tumor was performed. Grossly, fragments of the tumor measured 12 mm in diameter and polypoid/villous. Microscopically, it was a TVA indistinguishable from GI adenomas. No urothelium was seen, but a few normal prostatic glands were noted. The tumor showed mild to severe dysplasia, but in situ malignant transformation and invasive malignancy were not seen. Histochemically, acidic mucins were present. Immunohistochemical staining results of the tumor cells were as follows: cytokeratin(CK) AE1/3+++, CKCAM5.2+++, CD34BE12+, CK5+, CK6+, CK7++, CK14-, CK20+, EMA+, CDX-2-, CEA++, CA19-9++, CA125-, vimentin-, NSE-, NCAM-, synaptophysin-, chromogranin-, E-cadherin+++, beta-catenin+++, MUC1++, MUC2-, MUC5AC++, MUC6+, PSA+++, AMACR+++, AFP-, HepPar1-, p53-, KIT-, PDGFRA+, MET+, HER2-, Ki67+ (labeling = 5%). Myoepithelial cells were present in some areas. These results suggest the development and presence of a TVA in the PU indistinguishable from those in the GI tract, and it can arise from prostatic epithelium.

Perineuroma is a rare tumor originating from perineurium of the peripheral nerve. In contrast to neurofibroma and schwannoma, both of which arise from endoneurium and are immunohistochemically positive for S100 protein, perineuroma is negative for S100 protein; the fact makes the pathologic diagnosis difficult. As is well known, stem cells are highly associated with neuronal and organ developments in human embryos, and some neuronal cells are suspected to be derived from neuronal stem cells. Herein reported a very rare case of subcutaneous perineuroma negative for S100 protein but positive for a number of stem cell antigens; the case suggested that some perineuromas could arise from neuronal stem cells. A 68-year-old woman presented with a skin tumor of 10 mm in diameter in the foot. Physical examination revealed a small movable subcutaneous tumor, and resection was performed. Histologically, the tumor was a well-defined round tumor measuring 0.9 cm × 0.9 cm × 0.9 cm located in the subcutaneous tissue. No capsule was seen. The tumor was composed of hypocellular myxoid, neuroid tissues containing small areas of high cellularity where tumor cells resembled neuronal stem cells. Immunohistochemically, the tumor was negative for S100 protein, HMB-45, various cytokeratin (CK), EMA, α-SMA, desmin, p53, and many other antigens. The neuronal stem cell-like cells were positive for various stem cell antigens including NSE, KIT, bcl-2, chromogranin, synaptophysin, PDGFRA, MET, ErbB2, and CD34, as well as for vimentin and Ki-67 antigen (labeling index = 1.5%). Because the tumor was negative for S100 protein but positive for neuroendocrine molecules and neuronal stem cell antigens, the author diagnosed the tumor as perineuroma with stem cell features. Such a perineuroma has not been reported to date. The outcome of the patient was excellent.

Primary neuroendocrine carcinoma (NEC) except for Merkel cell carcinoma has rarely been reported in the skin. Herein reported is a unique case of a primary cutaneous NEC with histological features of squamous cell carcinoma (SCC) with high cellular anaplasia; the tumor is called “squamous NEC” in this report. A 77-year-old man presented with a skin tumor measuring 0.7 cm × 0.8 cm × 0.7 cm of the right second finger. A biopsy showed invasive malignant epithelial cells with keratinization. The carcinoma cells were continuous with epidermis, and showed high cellular anaplasia. No apparent lympho-vascular permeations were seen. The pathological diagnosis was poorly differentiated SCC. Because the histological features were unusual, an immunohistochemical study was performed. The carcinoma cells were positive for cytokeratin (CK) AE1/AE3, CK34BE12, CK5/6, neuron-specific enolase (NSE) (positive percentage (PP) = 70%), chromogranin (PP = 95%), synaptophysin (PP = 95%), NCAM (PP = 20%), p63, p40, S100 protein (Langerhans cells), and Ki-67 (labeling index (LI) = 98%). The carcinoma cells were negative for CK7, CK8, CK9, CK14, CK18, CK19, CK20, CK CAM5.2, smooth muscle actin, vimentin, desmin, HMB45, p53, CD45, TTF-1, HCG, and surfactant apo-protein. Because the skin SCC showed neuroendocrine features and the neuroendocrine cells exceeded 50% of the total tumor cell population, a diagnosis of squamous NEC was made. The histological features, NEC features, high anaplasia, and high Ki-67 labeling index (LI = 98%) suggested poor prognosis. Systemic investigations using CT, MRI, PET, and upper and lower gastrointestinal endoscopy revealed no tumors except for the finger tumor. No lympho-adenopathy was seen. The outcome seemed not good. The tumor of the finger was difficult for operation. Wide excision or finger amputation is considered.

The author herein reports a hitherto undescribed entity of cutaneous primordial carcinoma with triple differentiation into basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and porocarcinoma (PC) in a 66-year-old man. The patient was treated by tumor excision with wide margins. Pathologically, the margins were negative for tumor cells. The patient is now healthy 1 year after the excision. The tumor measured 3 cm × 2 cm × 2 cm and arose from the epidermis. The percentage of the occupying area was 60% in BCC, 20% in SCC, and 20% in PC. Histologically, BCC was characterized by basalioma cells, melanin pigmentation, peripheral palisading, and cleft formation, SCC by ample acidophilic cytoplasm, individual keratinization and cancer pearls, and PC by poroma cells and tubular structures containing cuticles. Cystic changes in BCC and SCC, keratotic nature of BCC, and acatholytic features of SCC were also seen in places. There were gradual merges among the three components. Immunohistochemically, BCC component was characterized by strong and diffuse expression of KIT, PDGFRA and p63, weak expressions of cytokeratin (CK) AE1/3, CK CAM5.2, CK34BE12, and negative expressions of CK18, CK19, CEA and CA19-9. SCC component was characterized by strongly positive expressions of p63, CEA, CK34BE12, CK7 and CK8, and negative expressions of CK18, CK19, and CA19-9. PC was characterized by strongly positive expressions of KIT, PDGFRA, CK34BE12, CK7, CK8, CK18, CK19, CEA, S100 protein, CA19-9, MUC1, and negative expression of p63. The present case revealed that there are primary cutaneous keratinocytic primordial carcinomas with triple differentiations into BCC, SCC, and PC. The present case is the first example of such tumors. It is thought that KIT and PDFRA-positive stem cells or cancer stem cells in the BCC component give rise to the SCC and PC components in the present case.

Leiomyosarcoma of spermatic cord is very rare. The patient is 65-year-old man who presented with a tumor in scrotum. Excision of tumor was performed and it showed a solid tumor measuring 4 cm × 3 cm × 3 cm in left spermatic cord. Histologically, it showed proliferation of hypercellular atypical spindle cells with hyperchromatic nuclei. The tumor cells were arranged with fascicles of cigar-shaped spindled cells with scant acidophilic cytoplasm. The tumor was not encapsulated, and mild invasive features into surrounding tissue were noted. The mitotic index was 17; 17 mitotic figures were seen in 10 high-power-fields. Atypical mitosis was also seen. Immunohistochemically, tumor cells were positive for vimentin, α-smooth muscle actin, h-caldesmon,desmin (focal), p53, and Ki-67 (labeling index = 34%). No other tumors were identified in the body, and the patient further treated with auxiliary local radiation and chemotherapy (cisplatin and doxorubicin). He is now healthy and free from tumors in the body 15 months after the operation.

Only 5 cases of follicular lymphoma (FL) have been reported in the prostate. A 68-year-old man presented with dysuria. Laboratory data did not indicate malignancy in the prostate with serums PSA of 4.6 ng/ml. Imaging techniques identified no tumors and lympho-adenopathy other than the prostatic enlargement. The patient was clinically diagnosed as prostatic hyperplasia, and trans-urethral resection of prostate (TURP) (65 g) was done. Histologically, the TURP-specimens showed severe nodular proliferation of atypical small lymphocytes consisting of small centrocytic lymphocytes and large centroblastic lymphocytes, the number of the latter being 2/HPF. Immunohistochemically, the tumor cells and nodular areas were positive for CD45, CD20, CD79a, bcl-2, bcl-6, and CD10. They were negative for pan-cytokeratin (AE1/3, CAM5.2), CD3, CD45RO, CD56, PSA, chromogranin-A, synaptophysin, NSE, CD138, CD15, CD30 and cyclin D1. No significant number of plasma cells were seen by immunohistochemistry for light chains and CD138. A pathological diagnosis of primary FL (grade 1) of the prostate was made. No tumors were identified by various imaging techniques, and the prostatic FL was diagnosed as primary. The patient underwent low-dose R-CHOP chemotherapy and focal radiation, probably resulting in complete remission. No recurrence has been found 5 months after the diagnosis.

Desmoplastic squamous cell carcinoma (SCC) and spindle cell SCC is very rare in skin. An 86-year-old woman presented a skin tumor of face. The tumor measured 1.8 cm × 1.6 cm × 0.6 cm. An excisional biopsy was performed. Histologically, malignant spindle cells with hyperchromatic nuclei and nucleoli were seen to proliferate together with marked solar elastosis and desmoplasia. Mitotic figures were scattered. Immunohistochemically, the malignant cells were positive for pancytokeratin AE1/3, pancytokeratin WSS, cytokeratin (CK) 5/6, CK34BE12, CK14, vimentin, S100 protein, α-smooth muscle actin, p53, p63, and Ki-67 (labeling = 70%). They were negative for EMA, pancytokeratin CAM5.2, CK7, CK8, CK18, CK19, CK20, desmin, HMB45, Melan-A, SOX10, MITF, myoglobin, CEA, CA19-9 and CD34. The lesion recurred two times and showed neck lymph node metastasis during the following 2 years. The patient died of other diseases 3 years after the first presentation.

Herein reported is the rare case of serous surface papillary cystadenoma (SSPC) of fallopian tube who presented with signs and symptoms of ectopic pregnancy. A 31-year-old woman presented with abdominal pain and elevation of serum human chorionic gonadotropin (hCG) (2,530 IU/L). Pelvic ultrasound examination suggested a rupture of right tubal pregnancy. Emergency laparotomy was performed, and right fallopian tube was resected. Pathologically, the fallopian tube was totally replaced by SSPC, but no evidence for pregnancy (chorionic villi, fetus, decidua, amnion, and cord) was seen. The SSPC was unilocular, and was surrounded by multiple papillary proliferations of serous cells with fibro-vascular cores, which were recognized both in the surface areas and in the intracystic inner aspects. The tumor cells of the SSPC were negative for hCG. After operation hCG returned to the normal range, and the patient was recovered with no complications. A rare case of SSPC of fallopian tube with pseudo-manifestations of ectopic pregnancy is reported. The raised serum hCG and its return to the normal ranges after the tube resection are completely unclear and enigma.

Primary extra-nodal NK-cell lymphoma of skin is extremely rare. A 55-year-old man presented with an elevated plaque of trunk. The dermatologists’ diagnosis was sporotrycosis and a biopsy was taken, which showed diffuse dense infiltrations of medium-sized and large atypical malignant lymphocytes. Epidermal hyperplasia and erosions were also seen. Immunohistochemically, the atypical lymphocytes were positive for CD45, CD56, CD57, p53 and Ki-67 (labeling index = 82%). They were negative for CD20, CD79, CD10, bcl-2, κ-light chain, λ-light chain, CD3, CD4, CD5, CD21, CD23, CD38, CD43, CD68, CD138, CD15, CD30, TdT, and cyclin D1. EBER was positive. The pathological diagnosis was primary cutaneous NK-cell lymphoma, nasal type. The post-biopsy blood test identified no leukemia findings. Post-biopsy imaginings revealed no mass and lymphadenopathy in the body. The skin lesions of the patient almost improved (complete remission) by chemotherapy (CHOP) followed by local radiation, and the patient is now followed up.

Primary cutaneous lymphoplasmacytic lymphoma (LPL) is rare. The author herein reports a case of LPL-like B-cell neoplasm with acute inflammation and epidermal cell atypia. A 69-year-old man presented skin ulcer of neck. The lesion appeared granulation tissue with surface fibrin deposition; an inflammatory process was suggested. Peripheral blood data showed no abnormalities, including the segments of leukocytes. No plasmacytosis was seen. No M-proteins, macroglubulins, or cryoglobulins were noted in serum and urine. The clinical diagnosis was non-specific skin ulcer. A wide biopsy was taken. It showed a destructive proliferation of atypical small lymphocytes, atypical plasmacytoid lymphocytes, and atypical plasma cells in dermis and subcutaneous tissue. The biopsy also showed acute inflammatory features; foci of many neutrophils were scattered in neoplastic cells. Some of them showed microabscesses. In addition, foci of atypical squamous cells were seen in the epidermis. Immunohsitochemically, the tumor cell showed B-cell lineage. The tumor cells were diffusely positive for vimentin, CD45, CD20, CD79, bcl-2, CD38, and CD138. The tumor cells were only focally positive for CD3 and CD45RO. A few tumor cells were positive for CD30, CD56, and CD10. Some of the tumor cells were positive for p53 and Ki-67 antigen (labeling index = 35%). The tumor cells were negative for pancytokeratin AE1/3, pancytokeratin CAM5.2, CD5, CD23, CD43, and cyclinD1. The tumor cells were positive for κ-chain but negative for λ-chain, indicating that the tumor cells have plasmacytic characteristics and that there was a light chain restriction which indicates monoclonal nature of the tumor plasma cells. The tumor cells were negative for Epstein-Barr virus (EBV) associated molecules such as EBV latent membrane protein-1 (LMP-1) and EBV early RNAs (EBER). A pathological diagnosis made by the author was cutaneous LPL-like B-cell malignant tumor. The author thought that this tumor could not be definitely diagnosed a primary cutaneous LPL, because other small-sized B-cell lymphomas with plasmacytoid differentiaton could not be excluded. The current tumor was also characterized by acute inflammatory features and epidermal squamous cell atypia suggestive of squamous cell carcinoma. Imaging modalities including CT identified no other tumors and lymphoadenopathy in the body. The systemic bones were free of myeloma features. No bone marrow study was performed after the pathological diagnosis. The tumor cured and the patient discharged from the hospital 3 months after the first presentation.

Primary malignant lymphoma of urinary bladder is extremely rare, and benign nodular lymphoid hyperplasia has not been reported in bladder. Nodular lymphoid hyperplasia of bladder associated with bladder carcinoma has also not been reported. Herein the author describe a 64-year-old man who presented with dysuria and his cystscopic examination revealed a papillary tumor in bladder. A transurethral resection of bladder tumor was carried out, and histopathologic examination revealed a non-invasive pTa low-grade papillary urothelial carcinoma and nodular lymphoid hyperplasia that were mixed up. The nodular lymphoid hyperplasia was composed of inner germinal centers and outer marginal and mantle zones. The germinal centers were composed of tangible body macrophages, centrocytes and centroblasts, while the outer zone of mature lymphocytes. Immunohistochemical profile of nodular lymphoid hyperplasia was as follows: cytokeratin AE1/AE3-, cytokeratin CAM5.2-, CD45+++, CD20+++, CD79a++, CD138-, CD3-, CD45RO-, CD15-, CD30-, p53- Ki67 80% (confined to germinal centers), bcl-2-, bcl-6++, CD10++, MUM1-, cyclinD1-, light chains-, CD56-, TdT-, CD68-. The patient is now followed up without any treatments by periodical cystscopy with BCG injection and cytology. No recurrence is noted 13 months after the first presentation. In conclusion, an extremely rare case of nodular lymphoid hyperplasia mixed with non-invasive urothelial carcinoma in bladder is reported.

Only a little is known about expressions of KIT (CD117) and platelet-derived growth factor-alpha (PDGFRA) in sebaceous carcinoma of skin; recently one report showed expression of KIT in 12/13 (92.3%) in sebaceous tumors. No reports of PDGFRA in sebaceous tumors are present. An 82-year-old woman presented a face tumor. Physical examination revealed a polypoid tumor measuring 0.8 cm × 0.7 cm × 0.7 cm with reddish ulcerations in cheek skin. A biopsy was diagnosed as basal cell carcinoma (BCC) with sebaceous differentiation by the pathologist. Further excision of the tumor with wide margins was performed. Histologically, the tumor was polypoid and located in dermis. The epidermis showed ulceration. The tumor was composed of solid nests of atypical cells showing invasive features into dermis. The margins were negative for tumor cells, and no lymphovascular invasion were seen. Numerous islands of bubbly sebaceous atypical cells were seen within solid carcinoma cells with hyperchromasia and nucleoli. Numerous mitotic figures including atypical ones were seen. Focal areas show trichilemmal keratinization. Histochemically, no mucins, argyrophil cells, or argentaffin cells were seen. Immunihistochemicallly, tumor cells were positive for cytokeratin (CK) AE1/3, CK 34BE12, CK5, CK6, CK14, p63, KIT, PDGFRA, MET, ErbB2, p53 and Ki-67 (labeling index = 82%). The tumor cells were negative for CK CAM5.2, CK7, CK8, CK18, CK19, synaptophysin, chromogranin, NSE, NCAM, S100 protein, vimentin, -smooth muscle actin, CD34, D31, HMB45, MUC1, MUC2, MUC5AC, and MUC6. The author diagnosed the tumor as sebaceous carcinoma. The patient is now well and has no tumor 18 months after the operation.

Prostatic carcinoma (PC) may present multiple metastases of unknown primary (most commonly bone metastases), the occult PC. PC expressing KIT and PDGRA has not been reported. There have been no reports of occult PC manifesting as a ureter tumor. An 83-year-old man presented with flank pain. Imaging showed a ureter tumor. Ureteronephrectomy was performed. The author diagnosed the ureteric tumor as high-grade urothelial carcinoma, Postoperative imaging showed multiple tumors in liver and lymph nodes. The clinical diagnosis was hepatocellular carcinoma and cirrhosis, and the patient received radiofrequency ablation (RFA). The patient further presented hematuria, and cystscopy revealed an elevated tumor of urinary bladder, and TUR-BT was performed. Histologically, TUR-BT specimens show monotonous medullar proliferation of high-grade malignancy arranged in solid nests and acinar formations. Immunohistochemically, tumor cells were positive for PSA, α-methyl CoA racemase (AMACR), cytokeratin (CK) AE1/3, CK CAM5.2, CK8, CK18, CK19, CEA, synaptophysin, KIT, PDGFRA, p53 and Ki-67 (labeling index = 90%). No mutations of KIT and PDGFRA were noted. Since PSA and AMACR were positive, the definite diagnosis of PC (Gleason 9) metastatic to multiple sites including ureter and bladder was made.

The author reports a rare case of extramedullary plasmacytoma (EP) of rectum. A 74-year-old man presented melena. Endoscopy revealed a polypoid tumor in rectum. Biopsy revealed poorly cohesive malignant cells resembling plasma cells. The biopsy was erroneously diagnosed by author as poorly differentiated adenocarcinoma. Resection of rectum was performed. Gross examination showed a polypoid tumor measuring 6 cm × 5 cm × 5 cm. Microscopically, the tumor was composed of poorly cohesive malignant cells resembling plasma cells. Three lymph nodes out of 29 lymph nodes dissected revealed similar malignant cells. Differential diagnosis was needed among plasmacytoid adenocarcinoma, signet-ring cell carcinoma, malignant lymphoma, EP, and poorly differentiated adenocarcinoma. Immunohistochemically, the tumor cells showed positive reaction for vimentin, p53, Ki-67 (labeling = 43%), CD45, CD20, CD38, CD138, CD79α, CD3, CD45RO, CD56, κ-chain and λ-chain. The tumor cells were negative for CK AE1/3, CK CAM5.2, CK WSS, CK34BE12, CK5/6, CK7, CK8, CK14, CK18, CK19, CK20, EMA, p63, CEA, CA19-9, CDX-2, NSE, synaptophysin, chromogranin, MUC1, MUC2, MUC5AC, and MUC6. The final pathological diagnosis was primary extra-medullary malignant plasmacytoma of rectum. Imaging techniques showed no other tumors in the body. The bones were normal, excluding multiple myeloma. The blood leukocytes and their segments were normal. The patient was treated by chemotherapy, and the disease cured. He died of other cause (pneumonia) five years after the operation.

Backgrounds: Clear cell adenocarcinoma (CCA) of urinary bladder (UB) is rare. Aims: To report a case of CCA of UB immunohistochemically expressing prostate-specific antigen (PSA), alpha-methylacyl-CoA racemase (AMACR) and CD10; thus this case was difficult to differentiate from metastasis from prostatic adenocarcinoma or renal cell carcinoma (RCC). Case: An 84-year-old man presented with dysuria and hematuria, and cystoscopy revealed a bladder tumor. The biopsy showed proliferation and invasion (more than pT2) of high-grade carcinoma cells focally forming glandular structures. Lymphovascular permeations were recognized. Focally, usual urothelial carcinoma (UC) was seen and there were gradual direct transitions between the clear cell carcinoma and UC. Immunohistochemically, the carcinoma cells were positive for PSA, AMACR, CD10, p53, Ki67 (labeling = 10%), uroplakin II, thrombomodulin, and cytokeratin (CK) 20, but negative for Hepatocyte-paraffin1 (HepPar1), CK7, PAX8, and TTF-1. Conclusions: A rare case of CCA of UB with immunoexpressions of PSA, AMACR and CD10 is reported. The aberrant expressions of these three antigens are only speculative. The gradual transitions between UC and CCA and the presence of urothelial antigens in this tumor suggest that the tumor might have originated from UC.

Backgrounds: Only a few cases of primary classical Hodgkin lymphoma (CHL) are reported previously in stomach. Case: A 77-year-old man presented epigastralgia and received an upper gastrointestinal endoscopy, which revealed multiple polyps. Biopsies (endoscopic mucosal resection) from the lesions showed proliferation of Hodgkin cells (HC) and Reed-Sternberg giant cells (RSC) mixed with non-tumorous inflammatory infiltrates composed of lymphocytes, plasma cells, neutrophils, and histiocytes. Immunohistochemically, the tumor cells (HC and RSC) showed the following immunophenotypes: cytokeratin -, CD45 +++, CD20 +++, CD10 ++. CD79a ++, CD138 +, CD3 -, CD45RO -, CD56 -, CD68 +++, CD30 -, CD15 +++, PAX5 ++, kappa-chain -, lamda-chain -, bcl-2 -, Ki67 20%, p53 +++, vimentin +++, CD68 +++, EMA -, CEA -, S100 protein -, smooth muscle actin -, CD31-, CD34-, factor 8 -, CEA -, EBER -, EBV-latent membrane protein1 -, and EBNA2 -. Immunostainings of endothelial antigens (CD31, CD34, smooth muscle actin, and factor 8-related antigen) showed negative results. A pathological diagnosis of CHL of mixed cellularity type was made, and the patient has first ABVD chemotherapy and then radiation. Conclusion: A very rare case of primary gastric CHL presenting multiple gastric polyps is reported.

Primary retroperitoneal malignant lymphoma is rare, and primary retroperitoneal indolent B-cell lymphoma has not been reported. A 64-year-old woman presented anuria. Imaging techniques showed large retroperitoneal mass, and biopsies from it revealed non-Hodgkin indolent B-cell lymphoma (small lymphocytic lymphoma/chronic lymphocytic lymphoma). The tumor appeared retroperitoneal primary and extra-nodal in locations.

Gastric mucinous myxoma (GMM), the author’s tentative terminology, has not been reported. The author reports the first case of GMM, a type of myxoma composed mainly of mucins. A 60-year-old man presented gastric discomfort, and received upper gastrointestinal endoscopy, which revealed a raised submucosal tumor (21 mm × 18 mm × 6 mm). He was treated by endoscopic submucosal dissection with a clinical diagnosis of GIST. Microscopically, the lesion was a GMM with well demarcation from surroundings but without capsule. In the periphery of the lesion, there were hyperplastic foveolar glands (HFG) containing much mucus. No epithelial elements were noted in GMM. There were many foci of gradual transitions between GMM and HFG, as if the HFG secrete mucins into the GMM. Histochemically, the GMM and HFG were positive for acidic mucins and neutral mucins. Immunohistochmeical results of the GMM were as follows: CK7-, CK20-, p53-, Ki67 1%, alpha-smooth muscle actin (ASMA)-, desmin-, MUC1-, MUC2-, MUC5AC+, and MUC6+. Immunohistochmeical results of the HFG were as follows: CK7+, CK20+/-, p53-, Ki67 5%, ASMA-, desmin-, MUC1-, MUC2-, MUC5AC+, and MUC6+. The author speculates that the HFG develops, then causes mucous hypersecretion and mucus submucosal accumulation, and then finally creates the GMM.

Primary small cell neuroendocrine carcinoma (SNEC) of uterine cervix is very rare; about 30 cases have been reported in literature. However, there have been no studies of KIT, PDGFRA, and bcl-2 in SNET of cervix. A 91-year-old woman presented vaginal bleeding which subsided by hemostatic drugs and balloon catheterization. Colposcopy showed a small tumor (6 mm) cervix and biopsy showed necrotic tissue and small atypical cells. They showed epithelioid features, small size, increased nucleo-cytoplasmic ratio, hyperchomatic nuclei, molded nuclei, scant cytoplasm, and absent nucleoli, thus fulfilling the criteria of SNEC of WHO. Immunohistochemically, tumor cells were positive for cytokeratin (CK) CAM5.2, CK AE1/3, CK7, CK8, CK18, CK19, NSE, synaptophysin, NCAM, KIT, PDGFRA, bcl-2, p53, and Ki-67 (labeling index = 100%). The tumor cells were negative for CK5, CK6, CK34BE12, CK14, CK20, EMA, chromogranin, CD45, CD138, CD20, CD3, CD99 (MIC-2), vimentin, S100 protein, α-smooth muscle actin, desmin, and myoglobin. Since neuroendocrine antigens (NSE, NCAM, synaptophysin, KIT and PDGFRA) were positive, a diagnosis of primary SNEC of cervix was made. Post-biopsy whole body studies revealed no other tumors. The patient rejected medical, surgical interventions because of very old age. She was followed-up, a mass of 5 cm was found in pelvic cavity. The patient is now alive 8 years after the diagnosis. The present case is the first of primary SNEC of cervix demonstrating positive KIT, PDGFRA, and bcl-2 proteins in a very old woman. The tumor was positive for many stem cells antigens, suggesting that the SNEC is a stem cell malignancy.