Hypophosphatemic osteomalacia with plantar neurilemoma. A review of the literature (100 cases).

A case of hypophosphatemic osteomalacia with recovery after removal of a plantar neurilemoma is reported. One hundred cases of osteomalacia with a connective tissue tumor were found in the medical literature. Both sexes and all age groups were affected. Patients often had severe osteomalacia with decreased serum 1,25 (OH)2 vitamin D and phosphate levels and renal phosphate wasting. These abnormalities resolved immediately after complete excision of the tumor, which was often a small lesion found after the diagnosis of osteomalacia. Of the 100 tumors, 87 were benign and half were vascular (e.g., hemangiopericytoma, hemangioma, angiofibroma). A large number of tumors could not be readily classified because they contained vascular structures, giant cells, spindle-shaped cells, and cartilage. Many other histologic variants were observed, including giant cell tumors, nonossifying fibromas, cartilaginous tumors, and osteosarcomas. The tumor was usually located in a limb, generally a lower limb, and was skeletal in nearly half the cases. The tumors produced one or more substances with a capacity for blocking intracellular phosphate transfer and inhibiting renal tube 1 alpha hydroxylase. The link between these two abnormalities remains unclear.