Tumor-induced osteomalacia: experience from three tertiary care centers in India. Issue 3 (March 2019)

• Record Type: Journal Article
• Authors: Pal, Rimesh; Bhadada, Sanjay Kumar; Singhare, Awesh; Bhansali, Anil; Kamalanathan, Sadishkumar; Chadha, Manoj; Chauhan, Phulrenu; Sood, Ashwani; Dhiman, Vandana; Sharma, Dinesh Chandra; Saikia, Uma Nahar; Chatterjee, Debajyoti; Agashe, Vikas
• Is Part Of: Endocrine connections. Volume 8:Issue 3(2019)
• Page Start: 266
• Page End: 276
• Publication Date: 2019-03
• Subjects: tumor-induced osteomalacia -- FGF23 -- hypophosphatemia -- phosphaturic mesenchymal tumor; Endocrinology -- Periodicals; 616.4005
• DOI: 10.1530/EC-18-0552
• Languages: English
• ISSNs: 2049-3614

Abstract

Abstract : Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome characterized by recalcitrant hypophosphatemia. Reports from the Indian subcontinent are scarce, with most being single center experiences involving few patients. Herein, we conducted a retrospective analysis of 30 patients of TIO diagnosed at three tertiary care hospitals in India. Patients with persistent hypophosphatemia (despite correction of hypovitaminosis D), normocalcemia, elevated alkaline phosphatase, low TmP/GFR and elevated or 'inappropriately normal' FGF23 levels were labeled as having TIO. They were sequentially subjected to functional followed by anatomical imaging. Patients with a well-localized tumor underwent excision; others were put on phosphorous and calcitriol supplementation. The mean age at presentation was 39.6 years with female:male ratio of 3:2. Bone pain (83.3%) and proximal myopathy (70%) were the chief complaints; 40% of cases had fractures. The mean delay in diagnosis was 3.8 years. Tumors were clinically detectable in four patients (13.3%). The mean serum phosphate was 0.50 mmol/L with a median serum FGF23 level of 518 RU/mL. Somatostatin receptor-based scintigraphy was found to be superior to FDG-PET in tumor localization. Lower extremities were the most common site of the tumor (72%). Tumor size was positively correlated with serum FGF23 levels. Twenty-two patients underwent tumor resection and 16 of them had phosphaturic mesenchymal tumors. Surgical excision led to cure in 72.7% of patients whereas disease persistence and disease recurrence were seen in 18.2% and 9.1% of cases, respectively. At the last follow-up, serum phosphate in the surgically treated group was significantly higher than in the medically managed group.