Fibrocartilaginous mesenchymoma arising in the pubic bone: a case report

Fibrocartilaginous mesenchymoma (FCM) of the bone is a rare tumor, with only 21 reported cases since 1984. It usually occurs in the long bones of children and adolescents, but in this case, the tumor arose in the pubic bone. The pathological diagnosis of FCM can be challenging, and the treatment should be a wide resection because of its locally aggressive behavior. Histologically, our tumor was composed of a lobular proliferation of spindle cells juxtaposed to the cartilaginous tissue, lacking cytological atypia. Enchondral ossification was observed at the periphery of the cartilaginous nodules, and hypertrophic chondrocytes was recognized, reminiscent of an epiphyseal plate. Intralesional resection followed by phenol and ethanol cauterization was performed in place of the usual wide resection. We report a case of FCM arising in a rare anatomical site, the pubic bone, successfully treated by intralesional resection. One year after the surgery, the patient is free of disease.