Hamartoma de músculo liso congénito: importancia de un correcto diagnóstico diferencial

Congenital smooth muscle hamartoma at unusual location

“…[23] The classic type presents a localized skin-colored or hyperpigmented plaque with prominent vellus hairs. It can vary in size, up to 10 cm in diameter.…”

“…[35] A hyperpigmented basal layer, acanthosis and hyperkeratosis can be found in the epidermis. [25] Histochemistry (i.e., Masson's trichrome) and immunohistochemistry (i.e., smooth muscle actin) are useful tools for revealing the nature of cell proliferation.…”

“…[3] Distinguishing CSMH from congenital melanocytic nevus might be difficult by using only clinical criteria. In fact, this is made by histopathological examination.…”

“…In contrast, CSMH forms more distinct and well-defined smooth muscle bundles with a characteristic clear space that surrounds each individual bundle, separating it from collagen fibers. [234] On the other hand, Becker's nevus resembles CSMH both clinically and histopathologically. Unlike CSMH, the hyperpigmentation and hypertrichosis of Becker's nevus increases over time and it is usually an acquired lesion that is diagnosed during the adolescent period.…”