A Case of Dermatomyofibroma

ABSTRACT

Dermatomyofibroma, first described by Kamino et al in 1992, is a rare plaque-like proliferation of fibroblasts and myofibroblasts of the skin. The lesion is a solitary plaque resembling a keloid or scar and is usually located on the shoulder and axilla. Histologically, the lesion is characterized by a proliferation of uniform spindle-shaped cells arranged as fascicles with a parallel arrangement to the skin surface. We report a case of dermatomyofibroma in a 47-year-old woman who had multiple, red papules and plaques on the left upper arm, left hand and right foot. The biopsy specimen obtained from the lesion of left upper arm showed fascicles of proliferations of uniform spindle-shaped cells and thin collagen fibers in the upper half of the dermis, which were arranged parallelly to the skin surface. Immunohistochemically, spindle-shaped cells stained positively for vimentin and smooth muscle actin, but were unstained for Keratin, S-100 protein, Factor VIII-R Ag and desmin.