A Case of Infundibulocystic Basal Cell Carcinoma Clinically Mimicking a Melanocytic Nevus Associated with Epidermal Cysts

Abstract

A 52-year-old Japanese woman presented with a 1.5-cm black, glossy, flat, pediculated lump that clinically mimicked a melanocytic nevus on the left temporal side of her head. The subcutaneous tumor beneath the nodule was elastic and hard. A histological examination showed that the tumor was well circumscribed with an exo- and endophytic growth 2.4 × 1.9 cm in size. The lesion contained several keratinous cysts and was composed of funicular fascicles containing squamoid cells. Excessive mucinous material deposition was observed around the tumor periphery and a palisading arrangement of nuclei in the tumor periphery was seen in some areas. Based on these findings, a diagnosis of infundibulocystic basal cell carcinoma (IFC-BCC) was made. This report presents a case of IFC-BCC that clinically mimicked a melanocytic nevus and was also associated with epidermal cysts.