A Case of Sebaceoma With Extensive Apocrine DifferentiationTanahashi, Jin MD, PhD*; Kashima, Kenji MD, PhD*; Daa, Tsutomu MD, PhD*; Kondoh, Yoshiyuki MD, PhD*; Yada, Naomi DDS, PhD*; Kuratomi, Eiji MD†; Yokoyama, Shigeo MD, PhD*The American Journal of Dermatopathology: August 2008 - Volume 30 - Issue 4 - p 408-411 doi: 10.1097/DAD.0b013e31817d2a4a Extraordinary Case Report Abstract Author Information Apocrine differentiation is a rare event in sebaceoma, and only 3 cases have been reported. We report a case of sebaceoma with extensive apocrine differentiation on the scalp in a 73-year-old Japanese woman. The resected tumor was located entirely within the dermis and subcutis as a well-circumscribed, lobulated, solid, and partially cystic mass, measuring 35 mm at the largest diameter. Histopathologically, it was composed of uniform basaloid cells with clusters of sebocytes, squamous islands of ductal structures, and apocrine cells with apparent decapitation secretion. Nuclear atypia of all types of cells was inconspicuous, and mitotic figures were infrequent. We considered the lesion to be a sebaceoma with apocrine differentiation. From the *Department of Pathology, Faculty of Medicine, Oita University, Yufu-shi, Oita, Japan; and †Department of Plastic Surgery, Oita Koseiren Tsurumi Hospital, Beppu-shi, Oita, Japan. Reprints: Jin Tanahashi, MD, PhD, Department of Pathology, Faculty of Medicine, Oita University, Hasama-machi, Yufu-shi, Oita 879-5593, Japan (e-mail: firstname.lastname@example.org). © 2008 Lippincott Williams & Wilkins, Inc.