Diagnosis and management of tumor-induced osteomalacia: a single center experience.

PURPOSE: The aim of this study is to review the clinical and laboratory characteristics, diagnostic and treatment modalities of tumor-induced osteomalacia (TIO) cases managed in a single center. MATERIAL METHODS: Demographic and clinical features, biochemical findings, diagnostic procedures, treatment modalities, and outcomes of nine patients who had the diagnosis of TIO were reviewed retrospectively. RESULTS: Mean age of the study group (F/M: 4/5) was 45.8 ± 10.8 years, and mean time from the onset of symptoms to diagnosis was 4.7 ± 2.8 years. The clinical manifestations were muscle weakness and difficulty in walking (8/9), hip pain (3/9), multiple fractures (2/9), stress fracture (2/9). Mean plasma phosphorus concentration was 1.28 ± 0.4 mg/dl at presentation. We performed radionuclide imaging modalities (18F-FDG PET/CT, Ga68-DOTATATE PET/CT, octreotide scintigraphy) in seven of nine patients, and tumor was detected in all. Lower extremity (n = 6; %67), head region (n = 2; %22) and thorax (n = 1; %11) were the tumor locations of our cases. Eight patients underwent surgery and remission was achieved postoperatively in all of the operated patients and plasma phosphorus level normalized in 4 ± 2 days. Pathological examination revealed mesenchymal tumors with different subtypes. Recurrence occurred in three patients at 13 ± 10.5 months after the first surgery. Two patients were reoperated and radiotherapy was also performed in one of them. CONCLUSION: Hypophosphatemia necessitates careful evaluation for the etiology. TIO is one of the important causes of adult-onset hypophosphatemic osteomalacia. Diagnosis of TIO is essential because the laboratory and clinical findings resolve after appropriate treatment.

Calcitriol treatment in patients with low vitamin D levels.

The aim of the the study is to compare the effects of cholecalciferol and calcitriol on bone mineral metabolism in women with vitamin D deficiency. Calcitriol was associated with a significant increase in bone mineral density at the lumbar spine in patients with low vitamin D levels. PURPOSE/INTRODUCTION: Active vitamin D analogs may have larger impact in decreasing bone loss and fracture rate compared to cholecalciferol in osteoporosis. However, their effects in the treatment of vitamin D deficiency compared to cholecalciferol are not clear. The aim of the present study is to compare the effects of cholecalciferol and calcitriol on bone mineral metabolism and bone mineral density in pre- and postmenopausal women with vitamin D deficiency. METHODS: This was a 6-month prospective, open-label, controlled clinical trial. Eligible 120 participants were pre- and postmenopausal women diagnosed with vitamin D deficiency. Forty-three subjects (group 1) received 1000 IU of cholecalciferol and 1 g of calcium daily. The other 77 subjects (group 2) received 0.5 µg calcitriol in addition to 400 IU of cholecalciferol and 1 g of calcium daily. RESULTS: Oral vitamin D supplementation did not increase bone mineral density after 6 months of intervention in group 1. On the other hand, bone mineral density at the lumbar spine increased from 0.809 ± 0.172 to 0.848 ± 0.161 g/cm2 in group 2 patients (p < 0.017 vs baseline). CONCLUSIONS: Oral daily calcitriol was associated with a significant increase in bone mineral density at the lumbar spine in patients with low vitamin D, elevated PTH, and osteoporosis.