Adnexa Cutis: Demystifying the plethora of Pilosebaceous and Sweat gland neoplasms

Abstract

Background: The neoplasms of the adnexa cutis arising from the pluripotent stem cell show differentiation towards one of the four adnexal cell lines i.e. follicular, sebaceous, eccrine and apocrine type. Categorizing these neoplasms into specific cell line differentiation and into benign or malignant is important, as malignant adnexal neoplasms are associated with a number of uncommon genetic syndromes and have an aggressive outcome. This study was conducted to primarily categorize these neoplasms based on their histological differentiation. Methods: Fifty-five cases of adnexa cutis that were reported over a four-year period were classified based on their histopathological differentiation and association with clinical parameters. Results: Thirty-three cases (60%) showed pilosebaceous differentiation with pilomatricoma being the commonest benign neoplasm. Twenty two cases (40%) showed eccrine differentiation. The most common malignant adnexal tumor was sebaceous carcinoma. (3 cases – 5.4%). Conclusion: All clinically suspected nodular/papular lesions should be subjected for histopathological examination and classified by differentiation to accurately determine the biologic behavior of the neoplasm. Key Words: Adnexa Cutis, Neoplasm