Dermoscopic findings of a congenital smooth muscle hamartoma in an infant

Follicular Becker's nevi: A case series and review of literature

The follicular variant of Becker's nevus is an under-reported entity. We present the rare occurrence of follicular Becker's nevus in 7 patients, confirmed through dermoscopy and histopathological examination. Dermoscopy shows perifollicular hypopigmentation surrounded by a well-defined net-like pigmentation corresponding clinically to the presence of folliculocentric macules. Histology shows prominent basal and suprabasal melanization surrounding the follicle, corresponding to well-defined net-like pigmentation seen on dermoscopy. However, the melanization does not extend along the entire length of the follicular epithelium leading to perifollicular hypopigmentation on dermoscopy. Though biopsy is confirmatory, it is not usually necessary.

Smooth muscle hamartoma and striated muscle hamartoma: Clinicopathologic characterization of two rare entities and literature review

Smooth muscle hamartoma (SMH) and striated muscle hamartoma (STH) are anomalous proliferations of smooth muscle or striated muscle, respectively, in anatomic sites where these tissues are normally present. To date, only limited cases have been reported describing these lesions. In this study, we sought to characterize the clinicopathologic features of both SMH and STH. A total of 27 cases of SMH and 12 cases of STH from 1990 to 2020 were identified. SMH cases had a slight male predominance (63%) and a mean age of presentation of 20 years (range: 4 months-91 years), with a mean size of 9.3 mm (±13.3). In contrast, STH were equally distributed in gender, with a mean age of presentation of 40 years (range: 3 months-66 years) and a mean size of 5.7 mm (±3.6). SMH were more commonly located in the torso and extremities (70%) and STH in the head and neck area (92%). One case of SMH recurred after 1.1 years and in the initial diagnosis the lesion was present at the tissue edge. None of the cases of STH had a recurrence. We present the largest cohort of SMH and STH, and report the first case of a recurrent SMH, suggesting the importance of obtaining a clean margin for these lesions.