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.

Pigmented infundibulocystic basal cell carcinoma: A diagnostic challenge in dark skin

“…However, morphological variations with lesions clinically mimicking melanocytic naevus and seborrhoeic keratosis have been described. 3,4 The importance of recognising this rare variant of BCC in dark skin phototype is twofold. Firstly, it needs to be differentiated from other variants of BCC due to its less aggressive behaviour as most of the lesions are slow-growing small tumours without ulceration.…”

“…It can occur as a solitary lesion or as a part of multiple hereditary infundibulocystic basal cell carcinoma syndrome. 2,3 The solitary form typically presents as a well-circumscribed slow-growing small (average diameter: 1-10 mm) dome-shaped superficial pearly papule or dermal nodule commonly on the face. However, morphological variations with lesions clinically mimicking melanocytic naevus and seborrhoeic keratosis have been described.…”