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

Abstract

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.

Rhabdomyomatous mesenchymal hamartoma presenting as telangiectasia in a 57‐year‐old man

“…11 There is no significant difference in disease prevalence between males and females. 1,11 Most cases of RMH are found in infants, but cases of teens, adults, and older adults (oldest 71-year old) have been reported. 2 Histopathologically, RMH is mainly characterized Although the etiology of RMH is unclear, two possible hypotheses have been suggested.…”

“…2 The mean size of the lesion is reported as 5.7 ± 3.6 mm in the literature. 11 There is no significant difference in disease prevalence between males and females. 1,11 Most cases of RMH are found in infants, but cases of teens, adults, and older adults (oldest 71-year old) have been reported.…”

“…Lesions present as nodules, papules, skin tags, or masses 2 . The mean size of the lesion is reported as 5.7 ± 3.6 mm in the literature 11 . There is no significant difference in disease prevalence between males and females 1,11 .…”

Presentation of a Smooth Muscle Hamartoma in the Bulbar Conjunctiva of an Adolescent Boy: A Case Report and Review of Literature

“…As previously stated, smooth muscle hamartomas in other sites have been reported as acquired lesions presenting later in life. 2 The key distinguishing factor between acquired and congenital lesions is the age of onset with no significant differences noted on histopathology. This case may be the first presentation of an acquired smooth muscle hamartoma in the conjunctiva.…”

“…They are generally observed in the skin of the trunk and proximal extremities and can be broadly classified as congenital or acquired. 2 Although uncommon, a smooth muscle hamartoma can manifest in the periorbita as a pink-tan lesion on the eyelid and eyebrow. 3 Conjunctival smooth muscle hamartoma has also previously been reported congenitally in infants 3 times.…”