Korean J Dermatol.
2024 Mar;62(3):165-168.
Congenital Smooth Muscle Hamartoma Characterized by Hypopigmented Appearance
- Affiliations
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- 1Department of Dermatology, Pusan National University School of Medicine, Busan, Korea
- 2Biomedical Research Institute, Pusan National University Hospital, Busan, Korea
Abstract
- Congenital smooth muscle hamartoma is a benign proliferation of smooth muscles within the dermis. The classic form presents as well-defined, skin-colored, or hyperpigmented plaques associated with hypertrichosis. However, there have been reports of atypical forms, including a follicular spotted appearance, linear atrophic plaques, and morphea-like forms. In such cases, distinguishing congenital smooth muscle hamartomas from other cutaneous diseases can be challenging. Herein, we report on a 16-month-old boy who presented with a hypopigmented patch and hypertrichosis on his back since birth. Histopathological examination revealed mild acanthosis and well-defined smooth muscle bundles haphazardly oriented in the dermis. These bundles stained positively with Masson’s trichrome stain. Based on these findings, a definitive diagnosis of congenital smooth muscle hamartoma was established. In conclusion, an exceptionally rare case of congenital smooth muscle hamartoma with a hypopigmented appearance is reported.
