Multiple Trichoadenomas of the Legs: Clinical and Dermoscopic Case Report

Abstract

Trichoadenoma is an uncommon benign adnexal tumour of follicular origin that usually presents as a solitary, slow-growing nodule, most frequently on the face. Multiple lesions and involvement of the lower limbs are unusual and may complicate clinical recognition because the external appearance is nonspecific. This case report describes a 42-year-old patient with no significant medical history who presented with multiple asymptomatic yellowish papulocystic lesions on both legs that had evolved progressively over one year. The lesions were bilateral and located on the extensor surfaces of the legs. Dermoscopic examination demonstrated small, grouped, rounded, poorly demarcated yellowish areas with a flaky appearance, together with a few serpiginous vessels. Histopathological examination confirmed trichoadenoma, showing an adnexal tumour composed of multiple keratin-filled cystic structures containing lamellar keratin, with a focal foreign-body-type reaction. The cysts were lined by regular epidermal epithelium, while the surrounding connective tissue showed fibroinflammatory changes. The bilateral multiplicity and lower-leg distribution represent an unusual clinical presentation. Dermoscopy provided supportive morphological information, but the observed structures are not specific and may overlap with other adnexal tumours and basal cell carcinoma mimickers. This case therefore emphasises the value of clinical, dermoscopic, and histopathological correlation while confirming that histopathological examination remains essential for accurate diagnosis.