Benign Sebaceous Epithelioma with Carcinoid-like Trabecular Cell Arrangement

A case of 75-year-old woman with sebaceous epithelioma was reported. The histological features were distinct in that it had a sinusoidal and carcinoid-like growth pattern, which has been reported in its malignant counterpart. Immunostaining for adipophilin was positive in the area with lipid-laden vacuolated cells, but the rest of tumor, which had cord-like nests, was negative. MIB index was 2%. CK5/6 and p40 were positive in the cord-like nesting areas. CK7, CK20, alpha SMA, and epithelial membrane antigen were negative in both the cord-like nesting areas and the adipose-like areas. The tumor was diagnosed as sebaceous epithelioma with a trabecular pattern. Dermatopathologists should be aware of this atypical histological pattern of benign sebaceous epithelioma.