A Retrospective Study of Phosphaturic Mesenchymal Tumours in a Tertiary Care Center

Background: Phosphaturic mesenchymal tumour (PMT) is a rare neoplasm with a distinct clinical presentation. It overproduces fibroblastic growth factor 23 (FGF23), a peptide-like hormone that decreases renal tubular phosphate absorption and inhibits 1α-hydroxylase, reducing 1α,25-dihydroxy vitamin D3 levels. It also mobilizes calcium and phosphate from bones and suppresses osteoblastic activity, resulting in osteomalacia. Given its rarity and unique biochemical profile, early recognition is crucial. This study reviews 14 cases of PMT reported in our institution.Methods: This study was conducted in the Department of Pathology, Amrita Institute of Medical Sciences, Kochi, Kerala and retrospectively identified fourteen cases reported as PMT from 2011–2020 from the institution's surgical pathology archives. Cases diagnosed histopathologically as PMT or those with osteomalacia and supportive DOTANOC scan or elevated FGF23 levels were included. Outcomes evaluated. Result: Fourteen cases were analyzed. Eleven were confirmed as PMT histopathologically, and three were diagnosed clinically, based on Ga-68 DOTANOC scan and high FGF23 levels. One case from the soft tissue near pyriform fossa showed features of low grade malignancy with necrosis, apoptotic debris and increased mitosis.Conclusion: The nonspecific presentation of PMT often delays diagnosis. Histopathology, serology, and detailed radiological imaging are valuable diagnostic tools. Complete surgical excision is curative, leading to resolution of osteomalacia, clinical symptoms, and abnormal laboratory parameters. Oncologists and pathologists should recognize this entity, as early diagnosis and treatment provide excellent outcomes.