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Abstract: Mucinous metaplasia (goblet cell type) is exceptionally rare in the skin. This is the second case of apocrine papillary hidrocystoma with mucinous metaplasia (goblet cell type) and a review of the literature exploring the significance and frequency of mucinous metaplasia with goblet cells in nongenital skin. The patient is an elderly man who presented with a blue-pigmented nodule on the scalp that was clinically suggestive of an atypical nevus. Histologically, the lesion was composed of a simple cyst of cuboidal cells with decapitation secretion and mucinous metaplasia with goblet cells. Papillary formation was identified in the cysts. Most cases of cutaneous mucinous metaplasia have been reported on genital skin, usually after chronic inflammation of the area. This type of mucinous metaplasia is categorized as benign mucinous metaplasia of the genitalia (BMM) and is believed to be unrelated to apocrine glands owing to the different histologic features and absence of apocrine differentiation by immunohistochemistry. Mucinous metaplasia (goblet cell type) has been previously reported in benign adnexal tumors (eccrine acrospiroma/hidroadenoma, mixed tumor, and syringocystadenoma papilliferum) and in malignant tumors (apocrine hidradenocarcinoma and squamous cell carcinoma). To date, mucinous metaplasia has not been identified in the histologically normal apocrine glands., Competing Interests: This manuscript has not been published previously and is not currently under review for publication elsewhere. There are no conflicts of interest to disclose at the time of writing. Please contact us with any questions or concerns, and thank you for your consideration., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Competing Interests: Conflicts of interest None disclosed.

Eccrine spiradenoma is a rare, benign, adnexal skin tumor of the sweat gland. It is frequently solitary and presents as a small lesion in the dermal or the subcutaneous fat layer. Eccrine spiradenomas rarely progress to malignant transformation but they can relapse. Due to its rarity, there have been few reports about the sonographic appearances of eccrine spiradenoma. Sonographic findings were reported in a relapsing case of an eccrine spiradenoma, located in the deep dermal layers and hypodermis of the preauricular region in a middle-aged man. Ultrasound was very useful to suspect the relapse. Histology was correlated with the sonography and discussed the previously reported imaging findings of eccrine spiradenoma and other sweat gland tumors., (© 2021. Società Italiana di Ultrasonologia in Medicina e Biologia (SIUMB).)

Abstract: Basal cell carcinoma (BCC) is the most common skin cancer, and it has numerous histologic mimics with variable prognoses and treatments. Although some immunohistochemical stains can be used for the differential diagnosis of BCC, variability and overlap in results can complicate their interpretation. Immunohistochemical staining for glioma-associated oncogene-1 (Gli-1) was performed on 26 nodular BCCs, 22 infiltrative BCCs, 9 basaloid squamous cell carcinomas, 12 desmoplastic trichoepitheliomas, 19 Merkel cell carcinomas, 11 sebaceous carcinomas, 10 cylindromas, 14 spiradenomas, 12 adenoid cystic carcinomas (AdCC), and 1 solitary trichoepithelioma. Strength of staining was scored as 0, 1+, 2+, or 3+, and distribution of staining was categorized as diffuse, multifocal, or focal. Strong, diffuse Gli-1 expression was seen in all tumors with basal epidermal-type differentiation, including BCC, trichoepithelioma, and basaloid squamous cell carcinoma. All examples of Merkel cell carcinoma were negative for cytoplasmic expression. Seven out of 11 sebaceous carcinomas were negative for Gli-1, and the remaining 4 showed 1+ expression. Cylindroma, spiradenoma, and AdCC, each an adnexal skin tumor, showed the most variable staining, but with cylindroma and spiradenoma demonstrating comparable labeling patterns. Overall, although Gli-1 may not distinguish between basal epidermal-type tumors, it may have a role in separating that group from lesions with adnexal differentiation, particularly sebaceous carcinoma, but also cylindroma, spiradenoma, and AdCC. Any cytoplasmic staining seems to exclude the diagnosis of Merkel cell carcinoma., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Spiradenocarcinoma (SC) is a very rare malignant skin adnexal tumor with sweat gland differentiation that develops from a pre-existing spiradenoma, cylindroma, or hybrid tumor called spiradenocylindroma, or arises de novo. We present two exceptionally rare SC cases showing sarcomatous differentiation; we also discuss the clinicopathologic features of SC, as well as its differential diagnoses and available therapeutic modalities. Given the aggressive behavior of SC, rapid diagnosis and complete removal of the tumor with tumor-free margins is mandatory. Owing to the marked morphological heterogeneity of individual SC cases, dermatopathologists must be familiar with the different possible histopathologic manifestations of this neoplasm., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Competing Interests: Competing interests: None declared.

Hidradenomas are benign sweat gland tumors that typically present as small nodules in adulthood. Their anatomic distribution is wide and rarely includes acral sites. In this setting, reliable separation from digital papillary adenocarcinoma is important, but notoriously difficult. Hematoxylin and eosin-stained sections of 25 hidradenomas on acral skin were retrieved. The clinical presenting features and morphologic findings were recorded, and follow-up was obtained. Immunohistochemistry was performed for AE1/3, CK5/6, EMA, CEA, SMA, S100, p40, and p63. The tumors presented as solitary nodules on the hands (n=17) and feet (n=8) of adults (age range: 20 to 81 y; median: 50 y), with an equal sex distribution. Histologically, the well-circumscribed tumors were lobular, with a solid and cystic growth within dermis. Duct and squamous differentiation and vascularized hyaline stroma were frequent. The majority (n=18) were poroid hidradenomas. Scattered cytologic atypia and mitotic activity (median: 2/10 HPF) were common, and a pseudoinfiltrative growth of strands in a hyaline to sclerotic matrix was noted in 5 tumors. No papillary structures, atypical mitoses, or tumor necrosis were present. Immunohistochemically, all tumors expressed AE1/3, CK5/6, p40, and p63 strongly and diffusely. Luminal differentiation was highlighted by epithelial membrane antigen and carcinoembryonic antigen staining. S100 and SMA staining was absent. Follow-up (1 to 288 mo; median: 61 mo), available for 20 patients, showed no local recurrences and no disease-related mortality. Acral hidradenomas and digital papillary adenocarcinomas share a well-circumscribed dermal growth pattern containing solid, cystic, and tubular areas with mitotic activity and at least focal cytologic atypia. Lack of papillary structures and the diffuse positivity for p40 and p63 in the absence of S100 and SMA expression are helpful features in favor of acral hidradenoma.

Aims: Hidradenoma papilliferum (HP) is a benign vulvar neoplasm that arises from anogenital mammary-like glands, and its morphology is similar to mammary intraductal papilloma. The aim of this study was to investigate oncogenic mutations involved in the tumourigenesis of HP. We focused specifically on PIK3CA and AKT1 mutations, which are both reported to be detected in 33% of mammary intraductal papillomas., Methods: In total, seven HP cases were analysed. Clinicopathological analyses and immunohistochemistry for oestrogen receptor, p63, smooth muscle actin (SMA), p53 and β-catenin were performed. Furthermore, PIK3CA , AKT1, BRAF and KRAS hot spot mutations were examined by Sanger sequencing., Results: Morphologically, all HPs had a papillary and tubular architecture with a biphasic pattern of epithelial and myoepithelial cells. Immunohistochemistry revealed that oestrogen receptor expression was restricted to epithelial cells, whereas p63 and SMA were exclusively expressed in myoepithelial cells. The patterns of p53 and β-catenin immunostaining suggested wild-type genotypes. Direct sequencing revealed the presence of somatic PIK3CA mutations (Ex9. c.1633G>A, p.E545K and Ex20. c.3140A>G, p.H1047R) in two of the HPs and an AKT1 (c.49G>A, p.E17K) mutation in one. BRAF and KRAS mutations were not found in any of the HP cases., Conclusions: PIK3CA and AKT1 are frequently mutated in HP tumours (29% and 14%, respectively). PIK3CA/AKT1 pathway alterations in HP further support the hypothesis that HP is the vulvar (anogenital mammary-like gland) analogue of breast intraductal papilloma., Competing Interests: Competing interestsNone declared., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)

Dear Editor, Apocrine hidradenoma is a rare benign adnexal tumor related to the more common poroma, as they both originate from sweat glands. Hidradenoma usually has an eccrine differentiation, but an apocrine differentiation is possible. Due to its rarity and non-specific clinical appearance it is difficult to differentiate it from other malignant cutaneous lesions. In this challenging task, dermatoscopy could be particularly helpful to better describe, recognize, and differentiate these lesions. Unfortunately, the literature offers only few dermatoscopic descriptions of this rare cutaneous neoplasm. A 70-year-old woman in fair general condition was referred to our Department for an asymptomatic 10×8 mm single nodule on her left scapula. This nodule was red, dome shaped, well circumscribed, firm, and mildly tender (Figure 1). The patient reported that it had been present since approximately 7 months. The lesion was neither painful nor itchy and there was no bleeding. A skin examination did not show any other lesions with the same features or other suspicious lesions. Dermatoscopy revealed milky-pinkish areas with dotted vessels, linear-irregular vessels, and hairpin vessels: some of these aspects can also be found in amelanotic melanoma (1). There were also homogeneous blue areas similar to lacunae, characteristic but not exclusive to vascular or sarcomatous neoplasms and basal cell carcinoma (1,2). Furthermore, small ulcerations covered by an amber crust were identified, which can usually be found in basal cell carcinoma. Regarding the background of the lesion, we noticed peculiar, translucent, pinkish, soft, large lobular areas (Figure 2). On the basis of this analysis, we suspected an atypical presentation of a basal cell carcinoma, an amelanotic melanoma, or a sarcomatous skin neoplasm. A metastasis of an unknown solid tumor was also taken into consideration. The histological examination revealed an adnexal neoplasm and specifically an apocrine hidradenoma. The neoplasm had variably sized nests and nodules of neoplastic epithelial cells, with a small ductular lumens confined within the upper dermis. The lesion was composed mainly of two cell types: polygonal and smaller, elongated, and darker cells. The cuboidal/polygonal cells were seen lining the duct-like spaces and slots and resembled those of poroma (Figure 3). The adnexal skin tumors group includes a complex variety of uncommon tumors that can be distinguished only histologically, and most of them are benign (3). Searching the literature for "hidradenoma dermoscopy" and "adnexal dermoscopy" yields multiple descriptions of poromas but few dermatoscopic descriptions of hidradenoma (4). There was only one report of the presence of "arborizing vessels"(5), and another described "reddish purple areas and some linear or hairpin-like vessels on the surface of the tumor" (6). In another paper we found: "irregular scar like whitish areas and a polymorphous vascular pattern including irregular reddish-purple areas mimicking lacunar appearance of hemangiomas with thick hairpin vessels at the periphery" (7). It is very difficult make use of such scant data especially in order to detect a leading pattern for a specific diagnosis. Moreover, the described structures lack in specificity, being also present in many other lesions. Analyzing our dermatoscopic image and comparing it to the other ones available in the literature, we identified a peculiar background. It consisted in the presence of multilobular translucent and pinkish soft areas, which fit the previously described dermatoscopic criteria. We hypothesize there is a correlation between this feature and the histopathological presentation with variably sized nests and nodules. Of course, further case reports of hidradenoma are needed to identify the soft lobular background as a distinctive dermatoscopic feature. Due to the lack of specific features both clinically than dermatoscopically, histopathological analysis remains the only gold standard for diagnosis of these benign mimicking lesions.

Background: Eccrine spiradenoma (ES) is a benign adnexal tumor predominantly located in the head and neck regions. Multiple neoplasms located on the scalp have been reported but never with a zosteriform configuration on the first trigeminal area., Case Report: We describe an original case report of a 75-year-old Caucasian man presenting multiple subcutaneous blue and purple nodules disseminated on the first left trigeminal dermatome. All the nodules appeared gradually on a one-year period. Biopsy revealed a nodular adnexal tumor in the dermis without malignant eccrine spiradenoma (MES) transformation. The surgical procedure was performed in a manner to protect the galea aponeurotica in the upper half on the first left trigeminal area. The frontalis muscle was raised with the surgical specimen in the lower half of the first trigeminal area. A split-thickness skin graft was applied on the surgical defect. Histological examination revealed multilobular well-defined tumors located in the dermis., Conclusion: The presence of multiple subcutaneous nodules in a trigeminal pattern should suggest a multiple localized zosteriform ES. The diagnosis is focused on clinical findings and the treatment is based on a large surgical excision. The histological examination is essential for not to fail a MES transformation., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

We present the case of a 44-year-old female with an aggressive digital papillary adenocarcinoma of the right thumb. Aggressive digital papillary adenocarcinomas are rare tumours originating from sweat glands of the skin on the hand or foot. The tumour was located at the extensor side and had been excised in 2 operations after diagnosis as an eccine hidradenoma, which is exceptional in this case. The tumour was radically excised and the defect was reconstructed using arthrodesis, and a retrogradely perfused pedicle radialis fascial flap with skin graft, due to which amputation was avoided., (© Georg Thieme Verlag KG Stuttgart · New York.)

Aims: Complex or composite adnexal tumours of the skin (CATS) are unusual neoplasms composed of two or more histopathologically distinct subtypes of appendageal neoplasms coexisting in a single cutaneous lesion. The authors report three examples of CATS, review literature and discuss their probable histogenesis., Methods and Results: Of the three tumours described, one tumour showed a mixture of a proliferating pilar tumour and syringocystadenoma papilliferum, the second lesion was composed of a proliferating pilar tumour and tubulopapillary hidradenoma and the third tumour exhibited a syringocystadenoma papilliferum and tubulopapillary hidradenoma in combination., Conclusions: CATS are rare tumours. The authors reported three unique cases in addition to the 10 other reported cases. These three cases further strengthen the hypothesis of a 'folliculosebaceous apocrine' unit as the most likely point of origin of CATS.

A 62-year-old man presented with a 2-year history of a 2-cm cystic mass involving his occiput. There had been recent enlargement, and the clinical impression was that of a pilar cyst. Histopathological sections showed a partially dermal solid and cystic proliferation. The tumor contained areas of glandular differentiation with cuboidal to columnar cells lining luminal and cystic spaces. A concurrent spindle cell proliferation was seen interspersed between glands and also formed broad, cellular sheets of cells. The stroma was sclerotic and without chondroid or myxoid elements. Immunohistochemistry showed that the spindled cells expressed S100 protein, cytokeratin and smooth muscle myosin. The immunohistochemical profile and the relationship with ductal elements supported myoepithelial differentiation. The proliferation warranted the diagnosis of myoepithelioma arising from a hidradenoma, which to our knowledge has not been previously described. In addition to discussing this case, we provide a brief review of epithelial-myoepithelial neoplasms encountered in the skin., (Copyright © 2011 John Wiley & Sons A/S.)

Eccrine acrospiroma, better known as eccrine poroma, is a benign adnexal neoplasm of the skin. Its clinical aspect can masquerade as some other nodular and cystic lesions. The current dermoscopy literature offers very few case studies. Moreover, these very few examples present a totally different appearance pattern compared to the one we examined. Its homogeneous blue pattern suggested the better-known nodular malignant melanoma; in fact, this dermoscopic appearance was due to the Tyndall effect.

Background: Adnexal carcinomas are rare and diverse cutaneous tumours. They are locally aggressive and have the potential for distant metastasis. Metastatic adnexal carcinomas are very resistant to conventional chemotherapies. Sunitinib, an oral tyrosine kinase inhibitor, is reportedly effective for the treatment of various solid cancers. Its use in adnexal carcinomas has never been reported., Observations: The first patient had metastatic clear cell hidradenocarcinoma and was stabilized over 8 months with sunitinib, before she relapsed. The second patient had a metastatic malignant hair follicle tumour (trichoblastic carcinoma) and achieved a partial remission with sunitinib, and disease stabilized after 10 months. Dynamic contrast-enhanced ultrasound (DCE-US) performed to evaluate tumour vascularization during treatment depicted a dramatic and early decrease in the tumour blood volume., Conclusions: Sunitinib was effective in controlling the disease in our two patients. DCE-US using linear raw data may have an early predictive value for tumour response to sunitinib. Further studies involving larger cohorts of patients are warranted in order to confirm the efficacy of sunitinib in these rare tumours.

Malignant eccrine spiradenoma (MES) is an extremely rare cutaneous malignant tumour. An 86-year-old man presented at our hospital with an enlarging tumour on the dorsum of the left hand. An excisional biopsy was taken and histological examination showed a solid island of cells of two distinct types: cells with abundant cytoplasm and oval vesicular nuclei, and small round cells with less cytoplasm and hyperchromatic nuclei with a high frequency of mitosis. We diagnosed this tumour as MES. Although we did not perform further treatment because of the patient's age, there was no sign of recurrence or metastasis in the 2 years of follow-up after excisional biopsy. We reviewed cases of malignant eccrine spiradenoma in the English and Japanese literature and found that 'sarcomatous' or 'squamous' change in histopathology was significantly correlated with a poorer prognosis. It is therefore important for treatment planning to evaluate the entire specimen histologically.

Eccrine porocarcinoma (EP), although rare, is widely recognized as the most common malignant sweat gland tumor. EP typically grows slowly and usually is cured by surgical excision with clear margins. An elevated mortality rate, however, is observed when regional lymph nodes are involved. We herein describe cytohistologic findings in a case of metastatic EP. An 86-year-old man with a history of EP of the left lateral ankle and squamous cell carcinoma in situ (Bowen's disease) of the penis presented with enlarged left inguinal lymph nodes. A superficial fine-needle aspiration (FNA) was performed and demonstrated a hypercellular sample with discohesive clusters and/or individual tumor cells. The tumor cells were round or oval with most of the cells showing dense, refractile cytoplasm. Intracytoplasmic vacuoles were readily appreciated in some of the cells. Nuclear enlargement, high N/C ratio, nuclear hyperchromasia, bi- and multinucleation, and prominent nucleoli were seen. A diagnosis of metastatic eccrine porocarcinoma was rendered. Enlarged retroperitoneal lymph nodes were detected and CT-guided left retroperitoneal core biopsy was performed 1 week later. The biopsy revealed features consistent with metastatic eccrine porocarcinoma., ((c) 2009 Wiley-Liss, Inc.)

Malignant eccrine poroma is a rare cutaneous neoplasm that originates from the intraepidermal portion of the eccrine gland. It affects mainly elderly people while its occurrence in younger adults is extremely rare. We present the first reported case of a malignant eccrine poroma in a pregnant woman, with emphasis on its pathologic and immunohistochemical features. Early diagnosis and treatment of eccrine neoplasms are of crucial importance when pregnancy coexists, because of their tendency to aggravate under the influence of gestation-related changes.

Bowen's disease rarely exhibits multiple combinations of premalignant and/or malignant skin lesions. Bowen's disease with invasive adnexal carcinoma was originally described by Kao, but is not well recognized by clinicians due to its rarity and lack of specific clinical features of this condition. Herein, we describe three unusual cases of Bowen's disease with invasive adnexal carcinoma. The two distinct neoplastic areas exhibited continuity both clinically and histologically. The plaque lesions possessed clinical features typical of Bowen's disease. In cases 1 and 3, we confirmed the adnexal tumor within tumors of Bowen's disease, the diagnosis of which is eccrine porocarcinoma. The tumor in case 2 was characteristic to trichilemmal carcinoma. Immunohistochemically, the tumor cells of Bowen's disease and the adnexal carcinoma differed in antigenicities. The present cases support a notion that Bowen's disease maintains a pluripotential nature.

Eccrine porocarcinoma may arise from eccrine poroma or it may occur de novo. We present a rapidly growing occipital malignant eccrine poroma on the scalp following to a radiotherapy for cervical carcinoma. A wide excision with skin grafting resulted no recurrence during a 1-year followup. Although malignant transformation is well known for other skin cancers this was not reported for eccrine poroma.

We describe a man with a pigmented poroma on the scalp mimicking a pigmented melanocytic nevus. Histopathological examination showed that melanocytes were mostly distributed at the periphery of the tumor masses. It is suggested that melanocytes in the tumor masses may have migrated from the adjacent epidermis.

We investigated the expression of CD10 by an immunohistochemical method in 51 basal cell carcinomas (BCCs), eight pilomatricomas, five trichoblastomas, two trichofolliculomas, three sebaceomas, five sebaceous carcinomas, ten syringomas, two spiradenomas, ten poromas, four porocarcinomas, one eccrine duct carcinoma (not otherwise specified, NOS), six mixed tumors of apocrine origin, and nine squamous cell carcinomas (SCCs). We detected strong expression of CD10 in tumor cells of BCC (86%), and found that the smaller the number of positive tumor cells, the larger the number of positive stromal cells, in particular in sclerosing BCCs. Spearman's rank correlation test revealed a significant negative correlation in BCCs between the expression of CD10 in tumor cells and that in stromal cells (P = 0.001). In all pilomatricomas (100%) and in four trichoblastomas (80%), strong expression was also detected in tumor cells. There was no detectable expression in trichofolliculomas. One sebaceoma (33%) and two sebaceous carcinomas (40%) expressed CD10 in a similar fashion to BCCs. All tumors of eccrine gland origin, including syringoma, spiradenoma, poroma, porocarcinoma, and eccrine duct carcinoma (NOS), did not express CD10. Five mixed tumors (83%) were immunopositive. In SCC, CD10 was overexpressed only in the stromal cells. These findings support the hypothesis that BCC is derived from the folliculo-sebaceous apocrine unit, especially having the same origin as trichoblastoma and pilomatricoma. CD10 might be an indicator of tumor invasiveness if it is expressed in stromal cells, while it might be a marker of follicular differentiation if it is expressed in the actual tumor cells of cutaneous epithelial neoplasms.

Background: Nodular hidradenocarcinoma was first reported as clear-cell eccrine carcinoma by Keasby and Hadley in 1954 (Cancer 1954;7:934-52) and rare malignant tumor. Several synonyms and related terms for nodular hidradenocarcinoma have appeared in the literature., Objective: They have potential for uncontrollable local recurrence, tend to metastasize, and often cause death. Most cases have been reported in the pathology literature with limited clinical information., Methods: We report a 27-year-old woman with nodular hidradenocarcinoma on the scalp., Result: The management of rare cases is not well defined. In our case, she was only treated with a wide local excision, and no recurrence was observed 2 years after excision., Conclusion: Most authors have concluded that early wide surgical excision of the tumor is the treatment of choice. The efficiency of adjuvant therapy generally has not established.

An 81-year-old woman came to our clinic (Department of Dermatology, Kaohsiung Medical University, Kaohsiung, Taiwan) with multiple erythematous, indurated papules over the left side of her face. Two years earlier, the patient had a skin biopsy done at a similar anatomical area with the histopathological diagnosis of Bowen's disease. After reviewing surgical specimens and confirming no systemic involvement, clear cell eccrine porocarcinoma with extensive cutaneous metastasis has been diagnosed. In addition, the peripheral blood lymphocyte function of the patient was evaluated. The expression of interleukin-2 receptors on lymphocytes after stimulation is abnormal compared with the age-matched normal control and a patient with cutaneous squamous cell carcinoma. This clinical manifestation of eccrine porocarcinoma is exceptional, and lymphocyte dysfunction in this patient has probably contributed to extensive cutaneous metastasis.

Malignant eccrine poroma is a rare skin tumor which commonly presents as verrucous plaques or polypoid growths. We report an 83 year old male who presented with an ulcerating eccrine poroma on the left arm. Though the tumor was excised with wide margins, axillary lymphadenopathy due to regional metastasis developed four months later, followed by lymphangitic cutaneous spread at six months. Though the prognosis for this tumor is better than previously thought, it still must certainly be considered potentially fatal.

A rare case of a syringoid eccrine carcinoma in a 52-year-old male patient is described. During the first hospitalization, syringoma was diagnosed, both clinically and histologically, keeping in mind the possibility of its malignant alteration. Difficulties in making a diagnosis with histological and immunohistochemical examinations are reported. The possibility of differential diagnosis of primary breast carcinoma and methods of its exclusion are also described. Treatment of the patient was surgical with good results.

Introduction: Eccrine sweat gland carcinoma, which belongs to the eccrine sweat gland carcinoma family, is a rare malignancy of the skin with a potential aggressive growth and metastatic spread., Exegesis: We report here a case of malignant eccrine poroma arising on the upper leg, with widespread pulmonary metastases., Conclusion: A brief synopsis of the pathological and clinical aspects of eccrine sweat gland carcinoma is presented with the currently available therapies.

A 75-year old woman without remarkable medical history presented with a large eccrine porocarcinoma of the trabelucar type located on her leg. This tumor was associated with two invasive squamous cell carcinomas of the legs, two Bowen's diseases of her thigh and arm and multiple actinic keratoses of the face. Despite major surgery, local recurrence of the porocarcinoma was observed 6 months later. During the 3-year follow-up after a second surgical intervention, this lesion did not reccur, but the patient developed a rapidly enlarging ulcerated tumor of the forehead which proved to be tricholemmal carcinoma. Although no carcinogenetic factor or familial history of multiple neoplasms could be evidenced, the occurrence of multiple tumors of various histogenesis over a 1 year period of time is unlikely to be fortuitous. Such an association of rare adnexal neoplasms has not yet been described.

Non-melanomatous malignant skin tumors of the hand are the same as those observed on other parts of the body, but with specific characteristics of frequency, aetiology, site and sometimes misleading clinical features. The author analyses these characteristics in relation to precancerous tumors: solar keratoses, arsenical keratoses, radiation dermatitis, kerato-acanthomas, Bowen's disease and malignant tumors: basal cell, squamous cell and other rarer carcinomas. He then outlines the principles of surgical treatment with reference to anaesthesia, usually local or regional, and resection, whose extent and depth depend on the nature and site of the lesion.

The relationship between clear-cell syringoma and diabetes mellitus is well established. We present a case of clear-cell porocarcinoma in a diabetic patient. The lesion consisted of a 5-cm nodule on the lateral aspect of the left leg. Histopathologically, the neoplasm was composed of irregular aggregations of neoplastic cells with striking clear-cell appearance, showing features of ductal differentiation. The clear-cell appearance of neoplastic cells was due to glycogen accumulation within their cytoplasm. Immunohistochemistry and ultrastructural studies also supported the diagnosis of a neoplasm with sweat ductal differentiation. Enzyme histochemical reactions for phosphorylase immunoreactivity on fresh, unfixed sections of the neoplasm demonstrated that this immunoreactivity was remarkably decreased. Some adnexal neoplasms of the skin mostly composed of clear cells may be cutaneous markers of diabetes mellitus. Phosphorylase activity deficiency in diabetic patients may be responsible for glycogen accumulation in neoplastic cells resulting in clear-cell appearance of these neoplasms.

Metaplastic carcinoma (carcinosarcoma, sarcomatoid carcinoma, malignant mixed tumor) is a biphasic tumor comprising malignant epithelial and heterologous mesenchymal elements. Primary cutaneous cases are rare, with only seven cases documented in the English literature to date. We present four further cases, including three that developed in association with squamous cell carcinoma and one in an eccrine porocarcinoma. Heterologous malignant mesenchymal elements included malignant osteosarcoma, chondrosarcoma, leiomyosarcoma, and rhabdomyosarcomas. In contrast to metaplastic carcinomas arising in visceral sites, those primarily arising in the skin do not appear to behave in a very aggressive manner (Recurrence rate 22%, metastasis rate 22%, overall mortality 11%). However, the numbers involved are small and the follow-up period is short. In view of recent developments and progress in our understanding of the possible histogenesis of such tumors, we suggest that metaplastic carcinoma rather than carcinosarcoma is the most appropriate term with which to describe these very rare cutaneous neoplasms.

The expression of cytokeratins in 10 cases of clear cell hidradenoma, including 3 cases of solid cystic hidradenoma, were examined using 21 kinds of monoclonal antibodies. We divided them into three histologic patterns: massive nests with a few lumina (M nests), nests with some tubular lumina (L nests), and nests in solid cystic hidradenomas (S nests). All hidradenomas showed similar immunoreactivities to those in the lower dermal ducts or secretory cells of normal eccrine glands. With antibodies against simple epithelial cytokeratins (CKs 7, 8, 18, and 19), however, different immunostaining was noted among the three histologic patterns. Namely, the M nests failed to react to them, although some luminal cells in the L nests revealed a positive staining. Furthermore, a majority of luminal cells in the S nests revealed a positive staining with them. Therefore, we think that the luminal cells in solid cystic hidradenoma mainly differentiate toward the secretory cells, and that the M nests mainly differentiate toward the dermal duct. Those in the L nests are thought to differentiate toward the dermal duct and the secretory cells. The proportion of the differentiation toward luminal cells of dermal ducts to the differentiation toward secretory cells was the main difference among the three nests. In addition, there was no difference in immunophenotypes between clear cells and epidermoid cells in the two kinds of hidradenomas.

Eccrine poroma, a common adnexal neoplasm, usually presents as a solitary, smooth, flesh-colored nodule on the foot or hand. Eccrine porocarcinoma is extremely rare and much more variable in its morphology and location. Both tumors can contain melanocytes and melanin. We describe a patient with an enlarging, eroded brownish black nodule on his shoulder. Examination of a biopsy specimen showed it to be derived from acrosyringium and to contain abundant melanin and scattered dendritic melanocytes. Eccrine poroma and porocarcinoma should be considered in the clinical differential diagnosis of pigmented tumors.

Background: Eccrine porocarcinoma is an uncommon neoplasm of the intraepidermal sweat gland duct., Methods: A case of porocarcinoma of the right heel in a male age 51 years is described with a review of pertinent literature. The surgically excised neoplasm was evaluated by routine histology and transmission electron microscopy., Results: The porocarcinoma showed extensive nuclear pleomorphisms with frequent, multinucleated tumor giant cells, focal epidermotrophic spread within the epidermis, a peripheral, eccrine syringofibroadenoma-like growth pattern, and an origin in a contiguous eccrine poroma. Ultrastructurally, the squamous tumor cells contained rare intracytoplasmic lumens., Conclusions: The extensive nuclear pleomorphism with frequent tumor giant cells was an unusual feature of the porocarcinoma. Its epidermotrophic spread within the epidermis and its origin in a contiguous eccrine poroma supported the diagnosis of porocarcinoma. The eccrine syringofibroadenoma-like growth pattern in the periphery of the tumor was a unique and previously undescribed feature of the porocarcinoma. The presence of intracytoplasmic lumens in squamous tumor cells mimicked embryonic development of the intraepidermal sweat gland duct.

A 68-year-old woman developed three reddish nodules on a linear epidermal nevus on the right arm. The nodules and linear lesion were resected. The histology revealed the two larger nodules to be eccrine porocarcinoma and the other to be eccrine poroepithelioma. The linear lesion was actually epidermal nevus. To our knowledge, this is the first description of adnexal tumors developing on epidermal nevus.

We describe six cases of benign eccrine poroma-like neoplasms with divergent adnexal differentiation. Four cases exhibited sebaceous differentiation in the form of individual or clustered sebocytes with or without sebaceous ducts. One case showed both sebaceous and hair follicle differentiation, and one case showed sebaceous and possible apocrine secretory differentiation. Clinically, most were skin-colored, red, or purple papules or nodules. One patient had a preoperative diagnosis of Bowen's disease, with an erythematous plaque. None recurred following biopsy. Previous reports of similar lesions have suggested a possible role for human papilloma virus (HPV) in their pathogenesis; however, immunohistochemical staining for HPV structural antigens was negative in all six of these cases. Similarities to previously reported cases of eccrine poroma-like neoplasms with sebaceous differentiation are discussed. Given the evidence of sebaceous and follicular differentiation seen in this study and the common embryologic origin of follicular, sebaceous, and apocrine structures, it follows that at least some benign neoplastic proliferations with histopathologic features of "eccrine" poroma could be of apocrine origin.