SOLITARY INFANTILE MYOFIBROMATOSIS OF BON E

Ne report one case of Solitary infantile Myofibromatosis of Bone in a 14-year old girl. Radiologic features of the tibial lesion were consis tent with the diagnosis of a benign bone tumor. The final diagnosis wa s made on a total resection of the tumor. Histologically, the tumor co nsisted of nodules, hyalinized or cellular, with spindle-shaped cells resembling fibroblasts or smooth-muscle cells. There were numerous vas cular spaces in close contact with these nodules. The tumor cells were immunoreactive with anti-alpha-smooth muscle actin antibodies. These data were consistent with the diagnosis of Myofibromatosis. The histol ogic features were similar to those of Infantile Myofibromatosis of ot her sites such as skin and soft tissue. The case reported is rare and not yet published due to the age and sex of the patient, and the locat ion of the tumor.