Postauricular sebaceous carcinoma arising in association with nevus sebaceus

Background. Sebaceous carcinoma is an uncommon malignant neoplasm usually associated with the ocular adnexa. Despite the widespread anatomic distribution of sebaceous glands, extraocular sebaceous carcinoma occurs with far less frequency. Methods. A 27-year-old man was examined with the presenting complaint of a slowly enlarging subcutaneous mass. It was associated with an overlying, irregular, verrucoid epidermal plaque. Results. Histologic and electron microscopic examination of the mass revealed a malignant sebaceous neoplasm occurring in conjunction with an overlying nevus sebaceus. The dermal neoplasm contained numerous cytoplasmic and stromal hyaline globules. Conclusions. We report a case of extraocular sebaceous carcinoma arising in the postauricular region in association with a nevus sebaceus and exhibiting the unusual histologic feature of hyaline globules.