Vitamin D Resistant Hypophosphatemic Osteomalacia Associated with Osteosarcoma of the Mandible: Report of a Case

Abstract

case of vitamin D resistant hypophosphatemic osteomalacia associcated with osteosarcoma of the mandible is presented. The patient complained of lumbar, knee and foot pain and muscle weakness of two years' duration. Serum phosphorus was 1.0-1.6 mg/dl, tubular reabsorption of phosphorus was 47 to 58%, TmP04/GFR was 0.7-1.2 mg/dl. Aminoaciduria was noted. Bone biopsy confirmed the diagnosis of osteomalacia. He partially responded to the treatment with 1α(OH)D3 and sodium phosphate. After removal of sarcoma of the mandible, symptomsremitted and pertinent laboratory data became normal except serum alkaline phosphatase for more than one year without treatment. It is suggested that an impaired response of the tubule and bone to active vitamin D3, caused in some way by the osteosarcoma might be one of the causes of osteomalacia in this case. © 1982, The Japanese Society of Internal Medicine. All rights reserved.