Cutaneous Neoplasms Arising in a Case of Muir-Torre Syndrome ; A Histopathological Study Based upon Proposed Updated Classification of Sebaceous Tumors

Abstract

We propose a new classification system for neoplasms with sebaceous differentiation. In this classification, neoplasms without differentiation other than sebaceous gland are classified into three categories : 1) sebaceoma, which is benign, 2) low grade sebaceous carcinoma, 3) sebaceous caroinoma. Based upon this classification, we histopathologically diagnosed 10 cutaneous tumors taken from a patient with Muir-Torre syndrome with a proven abnormality of a mismatch repair gene. One of the tumors was sebaceous carcinoma, seven were low grade sebaceous carcinoma, and two were sebaceoma. We partially disagree with the opinion of Ackerman and co-workers who claimed that sebaceous adenoma is sebaceous carcinoma and that neoplasms in all organs’ of Muir-Torre syndrome are carcinomas.