Clinicopathologic evaluation and restudy the tissue samples of cutaneous sebaceous tumors in a 30-year period

Cutaneous appendages give rise to various types of neoplasms which generally according to embryologic and histologic features are divided to pilocebaceous and sweet- gland tumors. Sebaceous tumors are a subgroup of the former that the accurate diagnosis of them is very important. Some of these tumors not only can be malignant and life threatening but also have many common and overlapping histologic features with some other benign and malignant cutaneous tumors that sometimes make them difficult to be diagnosed accurately. In addition, these tumors may be an alarm for an internal malignancy. The purpose of this study is to asses clinicoepidemiologic features of sebaceous tumors and histopathologically review and reclassify them by applying the new diagnostic criteria. Among 134748 archived tissue samples during a thirty-year period (1976-2005) In pathology department of Emam Reza University Hospital in Mashhad, all tissue specimen with a definite, probable, differential or uncertain diagnosis of any kind of sebaceous tumors were elicited. If necessary, new slides with conventional and special histochemical stains were prepared. All tissue slides were restudied, clinical data were gathered and presented in charts and tables and finally analyzed statically. Previous histopathologic diagnosis in 116 sebaceous tumors were confirmed, in 3 lesions, the diagnosis changed and 5 cases were excluded. 73 patients were men and 43 were women with a mean age of 34 year. These tumors included 66 nevus sebaceous, 24 sebaceous hyperplasia, 1 folliculo-sebaceous cystic hamartoma and 24 sebaceous carcinoma. In most instances previous pathologic diagnosis were correct and clinicoepidemiologic features were in accordance with other worldwide reported cases, although some considerable mistakes in previous diagnosis and differences in clinicoepidemiologic features were noted. Sebaceous tumors are relatively uncommon tumors mostly benign, occruing in both sexes in a broad range of age. Regional geographic and lesional differences may be observed in pattern of involvement. For an accurate diagnosis, the pathologist must pay special attention to the wide range of differential diagnosis and to apply definite histopathologic criteria regarding differences in pattern of involvement.