Dermatomyofibroma mimicking granuloma annulare.

We report the case of a 9-year-old girl with a lesion on the posterior aspect of the neck, which was clinically compatible with granuloma annulare. An incisional biopsy was performed and the result of the biopsy was consistent with a fibrohistiocytic proliferation. After the total excision of the lesion, the definitive diagnosis of dermatomyofibroma was determined. Dermatomyofibroma is a benign and rare proliferation of myofibroblasts of the skin. Dermatomyofibroma is a solitary and slowly growing tumor. It is more common in adolescents and young adults, with a female preponderance. Dermatomyofibroma presents clinically as a papule or nodule. It may be slightly hyperpigmented. It is usually located on the upper trunk, axilla, upper arm, or neck. The treatment of choice is complete excision and the prognosis is excellent.