Basal Cell Carcinoma in the Periungual Region: A Rare Case and Pathogenesis Insights

Abstract

This case report presents a rare occurrence of basal cell carcinoma (BCC) in the periungual region of the thumb. BCC is the most common type of skin cancer, typically found in sun-exposed areas. The discussion explores the underlying pathogenesis mechanisms, including the role of ultraviolet exposure, the absence of pilosebaceous units, and the involvement of the sonic hedgehog (SHH) pathway. Understanding the complexities of BCC in atypical locations is essential for effective prevention and treatment strategies.

Keywords: atypical areas; basal cell carcinoma (bcc); oncogenesis; periungual; sonic hedgehog.

Figure 1. Clinical image

A rounded plaque-like growth measuring 8 mm in diameter was observed on the proximal nail fold of the right thumb.

Figure 2. Dermoscopy

Dermoscopy revealed characteristic features of a non-melanocytic lesion, including redness, dotted appearance, globules, arborescent vessels, and areas of disrupted white coloration.

Figure 3. Hematoxylin and eosin stain

Hematoxylin and eosin stain depicts basaloid cell nests arranged in a palisading pattern within the top layer of the skin.