TUMOR-INDUCED OSTEOMALACIA

Tumor-induced (oncogenic) osteomalacia is a rare clinicopathologic ent ity in which the clinical signs and symptoms of osteomalacia and the s pecific laboratory abnormalities of hypophosphatemia, hyperphosphaturi a, and low serum levels of 1,25(OH)(2) vitamin D are associated with t he finding of a neoplastic process in the patient. To date, less than 100 cases of oncogenic osteomalacia have been described. We report a n ew case of adult-onset hypophosphatemic osteomalacia leading to the di scovery of an asymptomatic phosphaturic mesenchymal lung tumor. Comple te resection of the pulmonary neoplasia was followed by rapid normaliz ation of the laboratory findings and clinical remission. The clinical, laboratory, and histopathologic spectrum of tumor-induced osteomalaci a is presented, and the postulated mechanism of this condition is disc ussed in light of the relevant literature. The presence of occult neop lasms should be considered in cases of unexplained adult osteomalacia, with the physician's efforts being rewarded by the dramatic cure that follows excision of the tumor. (C) 1995 by W.B. Saunders Company