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Angiosarcoma (AS) showed diverse morphologies from well formed malignant vasculatures to poorly differentiated tumor with only a few clues of endothelial differentiation. Herein reported are two cases of AS without primitive vasoformative channels (VC). They showed, instead, a very few foci of intracytoplasmic vacuoles (ICV) that mimicked liposarcoma. The two cases were found in 12 cases of AS in computer database. Both are men, 57 and 68 years. One is cutaneous (foot) AS and another is soft tissue (thigh) AS. The largest diameter of cutaneous AS was 5 cm, and that of soft tissue AS 9 cm. The prognosis of both patients was poor; both died of metastases 4 and 6 years after initial presentation. In both cases, hematoxylin and eosin (HE) diagnosis was difficult because there were no VC, and most of the tumors were composed of primitive mesenchymal tissues. In both cases, however, a few very tiny foci consisting of ICV were seen. At first, the author considered them as mucins or fat, and suspected liposarcoma. In fact, they were pseudolipoblasts. Several mucin stains showed no mucins, and fat stains of frozen sections of formalin fixed tissue were negative for fat. Immunohistochemically, the vacuoles were positive for factor VIII-related antigen (F-VIII-RA), Ulex lectin, CD31, CD34, vimentin, p53 and Ki-67 (labeling index = 64% and 75%), but negative for various types of cytokeratins (CK), EMA, CEA, CA19-9, CD45, smooth muscle actins, S100 protein, myoglobin, HMB-45, Melan A, NCAM, and NSE. F-VIII-RA is specific and Ulex lectin and CD31 are relatively specific for endothelium. Therefore, the pathological diagnosis of AS could be made by the combined histologic features (ICV) and Immunohistochemical positivity of F-VIII-RA, Ulex lectin, and CD31. Thus, it appeared that the ICV may be the only clue of poorly differentiated or undifferentiated AS. In such undifferentiated cases, combined observations of meticulous histologic observations (intracytoplasmic lumens and ICV) immunohistochemistry of F-VIII-RA, Ulex lectin, and CD31 may be helpful in the diagnosis of poorly differentiated and undifferentiated AS. Electron microscopic observations were not done in the present study.

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 0.7×0.6×0.6 cm 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 2.5 years after the operation.

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.

Primary lymphoma of soft tissue is very rare. An 80-year-old man presented with a right buttock tumor measuring 5 × 5 × 4 cm. Tumorectomy was performed. The tumor was located in the fascia and subcutaneous tissue, and encapsulated by a thin capsule. Histologically, the tumor showed atypical lymphoid cell proliferation. Immunohistochemically, the tumor cells were positive for CD45, CD20, CD79a, and CD138. The Ki-67 labeling was 90%. In contrast, they were negative for pancytokeratins, epithelial membrane antigen, CD10, MUM1, bcl-6, cyclin D1, CD3, CD30, CD45RO, TdT, CD56, S100 protein, HMB45, chromogranin, α-smooth muscle actin, and desmin. A diagnosis of diffuse large B-cell lymphoma (DLBCL) of soft tissue was made. The subtype of DLBCL is non-germinal center type (non-GC). Systemic investigation using various imaging modalities including CT, MRI and Ga-scintigraphy revealed small nodular lesions up to 1 mm in the lungs and liver. However, biopsies of these locations were not performed because of his old age. The nodular lesions of the liver and lungs were small in diameter (up to 1 cm), and it is strongly likely that the buttock tumor is primary. The patient was treated by R-CHOP chemotherapy and radiation. He was referred to another specialized hospital for his will.

Prostatic carcinoma initially manifesting as only cervical lymph node swelling is a rare phenomenon. A 74-year-old man presented left cervical lymphadenopathy. An excisional biopsy was performed, and it was pathologically diagnosed as metastatic thyroid follicular carcinoma. However, imaging technique revealed no thyroid tumor or tumor in the body. The lymph node was re-examined 23 months after the first diagnosis: it showed adenocarcinoma positive for PSA and PSAH. Biopsy of the prostate was performed immediately, and it showed Gleason 8 (4 + 4) prostatic adenocarcinoma. Imaging technique showed two small metastases to pelvic bone. No other metastatic lesions were detected. The patient later developed acute myelogenous leukemia, and died of respiratory failure. The present case shows that prostatic adenocarcinoma can present only cervical lymph node swelling without metastases to other organs.

Primary signet-ring cell carcinoma (SRCC) of vermiform appendix is extremely rare; only three cases have been reported in the English literature. An 89-year-old man suddenly presented right lower abdominal pain, and transferred to a hospital, where he was diagnosed with acute appendicitis by physical data, blood data, and CT. He was further transferred to our hospital for emergency operation. Physical examination showed positive abdominal pain, Blunberg sign, and Rosenstein sign. Blood test showed leukocytosis and increased C-reactive protein. An appendectomy was performed. Gross examination during operation showed inflamed appendix, appendiceal adhesion, and acute peritonitis. Gross pathological examination showed no apparent tumor, but the proximal appendix showed wall thickening and luminal occlusion. The appendix was cut into three sections, and was observed under microscopically. Nests of carcinoma cells were seen in the proximal appendix. The carcinoma was composed of SRCC (70%) and mucinous carcinoma (30%). The size of carcinoma was 6 × 7 mm. The carcinoma cells invaded into muscular layer. No lymphovascular permeation was seen. The cut margins were negative for carcinoma cells. Immunohistochemically, SRCC cells were positive for cytokeratin (CK) AE1/3, CK CAM5.2, CK8, CK18, CK19, CK20, EMA, CEA, CA19-9, p53, Ki-67 (labeling = 30%), CDX2, MUC2, and MUC5AC. They were negative for CK34PE1, CK5/6, CK7, CK14, p63, vimentin, TTF-1, MUC1, MUC 5AC, NSE, synaptophysin, chromogranin, and CD56. No further treatments were performed, because the appendiceal carcinoma was small, the surgical margins were negative and the patient was very old. He was followed up by various imaging modalities. No recurrence or metastasis is found 17 months after the operation.

Background: Metastatic carcinoma manifesting as a mass in external auditory canal (EAC) is very rare, and prostatic adenocarcinoma (PA) presenting firstly as a mass of EAC has not been reported. Aim: To report a case of PA manifesting as only a mass of EAC. Case report: A 77-year-old man presented a right EAC mass. Otoscope identified a small mass approximately 7 mm in right EAC neat to the external orifice. Biopsy showed well differentiated adenocarcinoma with cribriform appearances. The author highly suspected metastatic prostatic PA (Gleason 4 + 4 = 8) and performed an immunohistochemical (IHC) study. The IHC showed positive prostate-specific antigen, prostatic acid phosphatase, alpha-methylacyl-CoA racemase, cytokeratin (CK) 7, and CK20. The tumor was negative for TTF-1, CDK2, and NCAM. The definite diagnosis of PA metastatic to EAC was made. The patient was referred to Urology and prostatic needle biopsy showed PA with immune-expressions of PSA, PAP, and AMACR. Serum PSA was high (63 ng/L). Imaging techniques showed a few metastases in bones of vertebula and ribs. The skull appeared free of metastasis, and head and neck soft tissue showed no metastatic areas except for the shadow of EAC. The patient is now treated with hormone and chemotherapy. Conclusion: The first case of an EAC mass that is a metastatic lesion of prostatic adenocarcinoma, was reported.