Smooth-muscle hamartoma. Possible congenital Becker's nevus

Congenital Smooth Muscle Hamartoma of the Skin

“…In a series of 33 leiomyomas (1) only 1 was present at birth, which was similar to our description; it may possibly signify CSMH, The leiomyoma, contrary to CSMH, is usually painful and can be differentiated histologicatly, being well circumscribed, with nodular proliferation of interweaving smooth muscle fibers (1,7).…”

“…The possibility of Becker's nevus being identical or associated with this hamartoma was suggested repeatedly (5,7,11). Becker's nevus, however, usually develops only later during the first or second decade and the pigment and hair number increase over time, while in CSMH, the intensity of color, induration, and hair appearance diminish after a few years.…”

Becker's melanosis: A report of 12 cases with atypical presentation

“…Becker's melanosis mainly consists of epidermal changes with only a minimal increase in smooth muscle, whereas CSMH is characterized by hyperplasia of smooth Alfadley et al Atypical Becker's melanosis Report muscle bundles throughout the dermis. 7,8 In both of our patients with congenital Becker's melanosis there was no smooth muscle hyperplasia. Only one of our patients (patient no.…”

“…Clinically both Becker's melanosis and congenital smooth muscle hamartoma (CSMH) are characterized by hypertrichosis and hyperpigmentation; some authors have suggested that Becker's melanosis and CSMH are variants of the same hamartomatous process. 7,8 In most cases of Becker's melanosis, however, the pigmentation and hypertrichosis are more prominent than in the smooth muscle component, whereas the reverse is true in CSMH. Becker's melanosis mainly consists of epidermal changes with only a minimal increase in smooth muscle, whereas CSMH is characterized by hyperplasia of smooth Alfadley et al Atypical Becker's melanosis Report muscle bundles throughout the dermis.…”

Clinicopathologic characteristics of early‐onset Becker's nevus in Korean children and adolescents

“…[5][6][7] Owing to these similar clinicopathological features, some authors suggested that BN and CSMH be included in the same spectrum of cutaneous hamartomas. 8,9 Others have characterized these two conditions as separate clinicopathological ª 2017 The International Society of Dermatology International Journal of Dermatology 2018, 57, 55-61 entities. 1,5,10 Hence, we evaluated the clinical characteristics of 103 patients who were diagnosed as having BN or CSMH in order to rediagnose for differential diagnosis.…”