Oncogenic osteomalacia caused by phosphaturic mesenchymal tumours in the proximal and shaft of the tibia: a case report

Oncogenic Osteomalacia: An Approach to Diagnosis with a Case Report

Oncogenic osteomalacia, also known as tumour induced osteomalacia, is a rare paraneoplastic syndrome caused by mesenchymal tumours secreting Fibroblast Growth Factor-23 (FGF-23). The characteristic biochemical findings include hypophosphatemia and low 1,25-dihydroxy vitamin D. The differential diagnosis for hypophosphatemia are varied. We present a case of oncogenic osteomalacia in a 29-year-old female, who presented with complaints of generalized diffuse bone pain and walking difficulty for six months duration. Thus, we have discussed the approach to diagnosis in such a case.

Perioperative management of patients with severe hypophosphataemia secondary to oncogenic osteomalacia: Our experience and review of literature

Oncogenic osteomalacia (OOM) is a rare paraneoplastic syndrome associated with mesenchymal tumours. It is characterised by phosphaturia, hypophosphataemia, decreased serum Vitamin D3 levels and severe osteomalacia. OOM-inducing tumours are usually benign, arising either from bone or soft tissue, with extremities and craniofacial region being the most common sites. Surgical resection of the tumour remains the mainstay of treatment. Challenges to an anaesthesiologist arise when such patients are planned for surgical resection of the underlying tumour. All the perioperative dilemmas are directly related to the severe hypophosphataemia. We describe three such cases of OOM and their perioperative management.

Phosphaturic Mesenchymal Tumor: 2 New Oral Cases and Review of 53 Cases in the Head and Neck

Phosphaturic mesenchymal tumor (PMT) is a rare neoplasm that secretes fibroblast growth factor-23 (FGF-23) and causes oncogenic osteomalacia. It occurs in adults with equal gender distribution and the most common location is the lower extremities, followed by the head and neck. Besides osteomalacia, the clinical presentation includes bone pain and multiple bone fractures. Microscopic features consist of spindle cells, multinucleated giant cells, and calcifications embedded in a chondromyxoid matrix. Laboratory findings indicate normal calcium and parathyroid levels, hypophosphatemia, and increased levels of FGF-23 that usually revert to normal after surgical removal. Due to its rarity, the purpose of the study was to report 2 new oral cases of PMT and to review the literature in the head and neck. The first case occurred in the gingiva and had been present for 6 years. The second case was a recurrence of a previously diagnosed PMT in the right mandible that metastasized to the lung and soft tissue. The literature review included 53 cases in the head and neck. There was a predilection for extra-oral sites (76%) compared to intra-oral sites (24%) with paranasal sinuses considered the most common location (38%) followed by the mandible (15%). There were 9 recurrences that included 3 malignant cases indicating a potentially aggressive tumor. Due to the indeterminate biological behavior of PMT and its rarity, a comprehensive evaluation of medical, laboratory, radiographic, and histological findings are crucial for a definitive diagnosis and treatment.