Musculoskeletal oncogenic osteomalacia-An experience from a single centre in South India.

Background: Oncogenic osteomalacia is an acquired form of hypophosphatemic osteomalacia where the tumour resection may lead to cure of the disease. Tumours originating from the musculoskeletal region form an important subgroup of oncogenic osteomalacia.

Methods: This was a retrospective study conducted at a tertiary care centre in south India where we analyzed the hospital records of all the patients with musculoskeletal oncogenic osteomalacia from January 2010-April 2016.

Results: A total number of 73 patients were diagnosed to have adult onset hypophosphatemic osteomalacia out of which 13 patients (M: F = 6:7; mean age: 45.38 ± 18.23 years) with musculoskeletal oncogenic osteomalacia were included in the study. Common presenting symptoms were bony pains, proximal myopathy and fractures. Mean duration of symptoms from the initial hospital visit was 58.46 ± 64.48 months. The initial mean fibroblast growth factor (FGF) 23 levels being 828.86 ± 113.22 RU/ml (Normal range: 22-91). Imaging modalities used for localization of the tumour: DOTATATE PET/CT (8 patients), FDG PET/CT (3 patients), 1 patient (Both DOTATATE PET/CT and FDG PET/CT) and whole body Tc 99 m Red blood cell (RBC) blood pool scintigraphy (2 patients). 9 patients underwent surgery and all achieved remission. 4 patients denied surgical consent.

Conclusion: Musculoskeletal oncogenic osteomalacia is a major subgroup of oncogenic osteomalacia which need more extensive whole body imaging for the localization of the tumour. Surgical excision often leads to remission of the disease.