Publication:

Spectrum of malignant skin adnexal tumors – a single institution study of 17 cases with clinicopathological correlation

Background Skin adnexal tumors are a rare, assorted group of tumors with differentiation towards hair follicle, sebaceous glands or sweat glands. A vast majority of them are benign. But for every benign adnexal tumor, a malignant counterpart exists. Many histological subtypes of these malignant tumors been described, but only in short series or individual case reports. So, not much is known about their incidence or prognosis simply because of the limited number of cases available for analysis. This study was undertaken to contribute towards this less traversed area of dermatopathology.

Methods In the present study, a total of 60 cases with a histopathological diagnosis of skin adnexal tumors were studied. The slides and blocks were retrieved from the archives and were reviewed and were reclassified and subtyped as per WHO classification of skin tumors, 2006.

Results Among the 60 cases of adnexal tumors documented and reviewed over the four year study period, 17 cases of malignant adnexal tumors were encountered. Of these, 10 (58%) were tumors with eccrine or apocrine differentiation, 5 (29%) were of follicular differentiation and two (12%) were of sebaceous differentiation. Mammary paget disease (MPD) was the most frequent malignant tumor encountered both overall and among the tumors with eccrine and apocrine differentiation. Other tumors encountered in their order of frequency were Malignant proliferating trichelemmal tumor, apocrine carcinoma, sebaceous carcinoma and extramammary paget disease, trichelemmal carcinoma and eccrine carcinoma. These tumors were evaluated with regard to their age, site, gender distribution, clinical characters and histopathological features.

Conclusion Malignant adnexal tumors are extremely rare with indistinct clinical characteristics. They are locally aggressive, and have the potential for nodal involvement and distant metastasis, with a poor clinical outcome. A high index of suspicion is necessary to establish a diagnosis in most cases.