A Case of Sporadic Nonfamilial Hypophosphatemic Osteomalacia / 대한내분비학회지

ABSTRACT

Acquired hypophosphatemic rickets, or osteomalacia, requires the recognition of the typical clinical and radiological features of osteomalacia in association with hypophosphatemia, which is caused by the decrease in intestinal absorption or impaired renal tubular phosphate reabsorption. The latter form may either be hereditary or acquired. Acquired hypophosphatemic osteomalacia includes oncogenic osteomalacia, neurofibromatosis, fibrous dysplasia, renal tubular acidosis and sporadic nonfamilial hypophosphatemic osteomalacia. A 33-year-old man presented with bone pain, progressive severe muscle weakness and a height loss of more than 10 cm over a 5 year period. The familiy history was negative for bone disease or other renal tubular defects. He was found to have hypophosphatemia, impaired phosphate reabsorption, normocalcemia, normal vitamin D metabolite levels, normal PTH and elevated alkaline phophatase. A bone biopsy showed thickened unmineralized osteoid compared to pelvic bone in control cases. Clinical symptoms, such as bone pain and muscle weakness, were improved after supplementation of oral phosphorus and calcitriol, although the serum phosphorus level did not normalize.