Solitary testicular myofibroma: a case report and review of the literature.

Myofibromas are benign mesenchymal neoplasms of myofibroblastic origin. Most present as solitary lesions at any age, but the presentation of multiple lesions in newborns and infants is known as infantile myofibromatosis. Multicentric lesions commonly involve soft tissues and bone and may involve internal organs, where they are associated with an unfavorable prognosis. Solitary lesions involving the viscera are rare. We report a case of a 3-month-old male infant with a left testicular mass detected during an evaluation for suspected torsion. The patient underwent orchiectomy, revealing a nodular mass with grossly evident foci of necrosis. Histologically, the lesion exhibited small fascicles of plump eosinophilic, smooth muscle actin-positive spindle cells, alternating with larger areas of primitive cells with vesicular nuclei and scant cytoplasm arranged around a hemangiopericytoma-like vasculature. To our knowledge, this is the first report of a myofibroma localized within the testis.