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Poroma 1
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Sebaceous differentiation in poroid neoplasms: report of 11 cases,
including a case of metaplastic carcinoma associated with apocrine
poroma (sarcomatoid apocrine porocarcinoma). We describe 11 poroid neoplasms with sebaceous differentiation, including a metaplastic (sarcomatoid) carcinoma arising in association with an apocrine poroma. Six lesions had the silhouette of a classical poroma, 3 of poroid hidradenoma and 1 of dermal duct tumor. In all cases, sebaceous differentiation was identified as clustered or solitary, mature sebocytes occurring mainly at the periphery of intradermal cellular aggregations, accompanied by sebaceous ducts. In one poroma, clusters of sebocytes were seen within intradermal aggregates and intraepidermally. In 1 of the 3 poroid hidradenomas, the eosinophilic cuticle lining the cyst was crenulated in foci associated with sebocytes. In none of the cases were there signs of follicular differentiation. One poroma, in addition to sebaceous differentiation, showed decapitation secretion in some ductular structures. The single carcinoma was an ulcerated oval to spindle cell neoplasm surrounded laterally by the residuum of a poroma containing groups of sebocytes. The epithelial islands of the poroma were prominently keratinized and blended gradually with the pleomorphic cells of the metaplastic carcinoma that immunohistochemically stained focally for cytokeratins and simultaneously showed strong vimentin expression. Our study supports previous findings that sebaceous differentiation can be identified not only in classical poroma but also in the related lesions known as dermal duct tumor and poroid hidradenoma. Occurrence of metaplastic carcinoma in association with apocrine poroma is a rare event which indicates the existence of a malignant counterpart of the latter entity, which can be descriptively referred to as "sarcomatoid apocrine porocarcinoma." |
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Pigmented eccrine poromas:
expression of melanocyte-stimulating cytokines by tumour cells does
not always result in melanocyte colonization.J
Eur Acad Dermatol Venereol. 2008 Mar; 22(3): 303-10. BACKGROUND: Although eccrine poroma (EP) occurs preferentially in palmoplantar areas, pigmented variants of EP have not been documented on the palms and soles. OBJECTIVES: We seek to confirm the notion regarding lack of pigmented EP on palmoplantar areas and determine whether the absence of pigmentation in palmoplantar EPs is due to lack of expression of melanocyte-stimulating cytokines by tumour cells. METHODS: We searched the PubMed and Web of Science databases (1966-2006) for reports of pigmented EPs. In addition, a total of 17 EPs were collected from our pathology department. The presence of melanin was examined with haematoxylin-eosin sections, and melanocyte colonization was shown by immunohistochemical stains for tyrosinase. In addition, immunohistochemical staining with antibodies to melanocyte-stimulating cytokines, including endothelin-1, stem cell factor, and nerve growth factor, was done on these tumours. RESULTS: A review of the literature revealed 15 pigmented EP reports, none of which were located in palmoplantar areas. Among 17 EPs collected from our pathology department, 7 occurred in palmoplantar areas and 10 in non-palmoplantar areas. Three of the palmoplantar EPs and three of the non-palmoplantar EPs showed positive staining with melanocyte-stimulating cytokines. However, none of the palmoplantar EPs contained melanocytes or melanin pigment, wheras the three non-palmoplantar EPs that stained positively with melanocyte-stimulating cytokines were colonized with melanocytes and showed pigmentation clinically. CONCLUSIONS: The expression of melanocyte-stimulating factors by tumour cells is associated with melanocyte colonization in non-palmoplantar EPs but not palmoplantar EPs. Therefore, the presence of melanocyte-stimulating cytokines per se is not sufficient by itself to induce melanocyte colonization. Certain characteristics of palmoplantar skin, such as the dermal components of these anatomical sites, may play a role in inhibiting melanocyte colonization of EPs. |
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