Pigmented eccrine poroma in collision with seborrheic keratosis: Dermoscopic description and histological correlation

Abstract

Poromas are rare, benign neoplasms arising from the terminal ductal portion of the sweat glands. They are mainly characterized by flesh-colored or pink papules or nodules, usually located at the extremities. The pigmented variant is rare. Collisions with other benign epithelial tumors have been reported. The clinical appearance may be confused with several benign or malignant tumor pathologies, yet thanks to dermoscopy, which is a non-invasive means of exploration, some signs are highly useful in the diagnosis and in suspecting the collision of two distinct tumors before proceeding to histological confirmation. Herein, we report the original case of a collision between pigmented eccrine poroma of the leg and seborrheic keratosis. Key words: Pigmented poroma; Collision; Dermoscopy; Histology; Seborrheic keratosis