Solitary cutaneous myofibroma of the glans penis.

In the present report, we describe a cutaneous myofibroma with a monophasic pattern. The patient was a 12-year-old white boy with an asymptomatic yellow nodule on his glans penis for about 2 1/2 months. The nodular pattern of growth is distinctive: nests of plump spindle cells with a tendency toward interstitial hyalinization within the dermis. Confirmation of the myofibroblastic nature of the proliferation was obtained by histochemical and immunohistochemical studies. The tumor cells showed immunoreactivities for vimentin, alpha-smooth-muscle actin, and collagen type IV but did not stain for desmin. To the best of our knowledge, this is the first case of cutaneous myofibroma to occur on the glans penis. This tumor should be included in the differential diagnosis of mesenchymal neoplasms of the penis.