Tumor-induced osteomalacia: long-term follow-up of two patients cured by removal of their tumors.

Two patients with mesenchymal tumors had osteomalacia associated with marked hypophosphatemia and renal phosphate wasting. Their serum calcium and parathyroid hormone levels were normal. The first patient also had aminoaciduria and glucosuria in addition to phosphaturia. Both patients were treated with very large doses of vitamin D2 and phosphate without improvement in the osteomalacia or normalization of the serum phosphate. Complete removal of a low-grade fibrosarcoma in the second patient and removal of an ossifying fibroma in the first patient resulted in a cure in both patients despite no further therapy with vitamin D or phosphate. The excessive aminoaciduria and glucosuria of the first patient also remitted. During a 14-year follow-up period, there has been no evidence of tumor recurrence, hypophosphatemia, or osteomalacia in either patient. The levels of 1,25-dihydroxycholecalciferol remain within the normal range in both patients.