Extramammary Paget Disease of the Axilla Associated With Comedo-like Apocrine Carcinoma In Situ

Abstract

Extramammary Paget disease of the axilla with underlying apocrine carcinoma has been reported only in six cases until now. This report deals with a seventh case characterized by the unique finding of comedo-like features evocative of large cell ductal breast carcinoma within an otherwise typical in situ apocrine carcinoma. This is characterized by spiral-shaped foci of epithelial proliferation with decapitation secretion and central masses of necrotic debris. A possible connection between the solid neoplasm and the overlying Paget disease is illustrated by a few apocrine-follicular units colonized by both the Paget cells and the structured adenocarcinoma. Here, although they display the same immunohistologic pattern of glandular differentiation, the two populations seem to be cytologically different and do not show signs of gradual transition to one another. Thus, they give the impression of parallel but distinct processes, which is consistent with the hypothesis of proliferative induction of a preexisting intraepidermal scattered population from the underlying adnexal carcinoma. The observed resemblance between apocrine carcinoma and comedo carcinoma of the breast, with its ontogenetic and phylogenetic implications, links not only the two neoplasms and the corresponding glands of origin but also mammary and extramammary Paget disease. This reinforces the unifying conception of Paget disease.

Primary cutaneous apocrine carcinoma arising within a congenital nevus: Keratins and filaggrin expression suggesting differentiation into the secretory cells of apocrine glands

“…our findings are consistent with previous research in the literature which showed that PCAC is negative for α-SMA (smooth muscle actin), a useful marker of myoepithelial cells (15,24). An ultrastructural study also found that PCAC, which displayed microvilli on the surface of the tumor cells under an electron microscope, showed differentiation into secretory cells (14,25).…”

Apocrine Carcinoma In Situ of Sweat Duct Origin

“…' The published literature on in situ apocrine sweat lesions is scarce; however, there have been isolated case reports of pure in situ carcinoma. 1,2,4 Other invasive apocrine carcinomas of the skin that have contained an in situ component have also been previously described. 7,8 There have been a total of 9 cases of in situ sweat gland carcinoma, all of which were either high grade with comedonecrosis or with no specified grade mentioned.…”

“…7,8 There have been a total of 9 cases of in situ sweat gland carcinoma, all of which were either high grade with comedonecrosis or with no specified grade mentioned. 1,2,4,7,8 Of the cases that have specified a site of origin, all have occurred in the axilla; (the most common site of invasive apocrine carcinoma), or in the anogenital region where the so-called mammary-like glands (MLG) are found. 1,2,4,8 We have also recently seen 2 in situ apocrine lesions of the scalp; a previously unreported finding.…”

“…1,2,4,7,8 Of the cases that have specified a site of origin, all have occurred in the axilla; (the most common site of invasive apocrine carcinoma), or in the anogenital region where the so-called mammary-like glands (MLG) are found. 1,2,4,8 We have also recently seen 2 in situ apocrine lesions of the scalp; a previously unreported finding. Both had the appearance of apocrine atypical ductal hyperplasia (ADH) or ductal carcinoma in situ (DCIS) of the breast.…”

“…5 Only 3 cases of pure apocrine in situ carcinoma have been described, all of which were high grade with comedonecrosis and no evidence of invasion. 1,2,4 In total, there have been 9 cases of in situ sweat duct carcinomas. 1,2,4,7,8 Five of these were not specifically separated into eccrine or apocrine varieties.…”