Oncogenic osteomalacia secondary to hemangiopericytoma: a case report

<p>We are going to present a case of hypo-phosphatemic rickets secondary to phosphaturic mesenchymal tumour who came with complaints of proximal muscle weakness which limited his effort tolerance and activities of daily life like standing from squatting position and rib pain. His FGF-23 levels were very high above normal levels and PET CT revealed a well-defined enhancing lesion abutting femoral neurovascular bundle. After consultation with endocrinologist, we have d done complete excision of the mass. Post-surgery all symptoms were relieved, proximal muscle strength improved gradually and serum levels of phosphorus, ALP and FGF-23 came back to normal.</p>

Phosphaturic mesenchymal tumors: radiological aspects and suggested imaging pathway

Phosphaturic mesenchymal tumors (PMTs) are rare mesenchymal neoplasms of soft tissue or bone origin that can give rise to a challenge in diagnostic imaging. These tumors are frequently associated with tumor-induced osteomalacia, also called oncogenic osteomalacia, which is a rare paraneoplastic syndrome characterized by ectopic secretion of fibroblast growth factor 23, a hormone that regulates serum phosphate level. PMTs show polymorphic features on both radiological findings and histological examination, causing problems in diagnosis owing to their similarity with other mesenchymal tumors. Thus, this paper aims to describe radiological aspects of PMTs and suggest an imaging pathway for accurate diagnosis throughout the evidence from the literature review.

A Case of Hypophosphatemia due to Oncogenic Osteomalacia in a Patient with Natural Killer T-Cell Lymphoma

<b><i>Introduction:</i></b> Oncogenic osteomalacia (Onc-Ost) is a paraneoplastic phenomenon characterized by hypophosphatemia due to elevated fibroblast growth factor-23 (FGF-23). Onc-Ost has been previously reported in patients with germ line mesenchymal tumors and solid organ malignancies. This is the first report of aggressive natural killer (NK) T-cell lymphoma presenting as Onc-Ost. <b><i>Case Description:</i></b> A 33-year-old Vietnamese female with active hepatitis B and <i>Mycobacterium avium</i> complex, on ongoing therapy with tenofovir disoproxil, azithromycin, and ethambutol, presented with persistent fevers and developed refractory hypophosphatemia. Workup confirmed severe renal phosphate wasting. Tenofovir disoproxil was initially suspected; however, presence of isolated phosphaturia without Fanconi syndrome and persistence of hypophosphatemia despite discontinuation of medication led to clinical suspicion of Onc-Ost. Elevated FGF-23 warranted further workup, leading to a definitive diagnosis of clinically subtle NK T-cell lymphoma. Chemotherapy was initiated; however, patient continued to deteriorate clinically and expired. <b><i>Conclusion:</i></b> Along with commonly reported germ line mesenchymal tumors and solid malignancies, NK T-cell lymphoma can also present as Onc-Ost. Timely detection of associated tumors and subsequent antitumor therapy would likely reverse hypophosphatemia and improve clinical outcomes.

Oncogenic osteomalacia secondary to glomus tumor

Summary Oncogenic osteomalacia secondary to glomus tumor is extremely rare. Localization of causative tumors is critical as surgical resection can lead to a complete biochemical and clinical cure. We present a case of oncogenic osteomalacia treated with resection of glomus tumor. A 39-year-old woman with a history of chronic sinusitis presented with chronic body ache and muscle weakness. Biochemical evaluation revealed elevated alkaline phosphatase hypophosphatemia, increased urinary phosphate excretion, low calcitriol, and FGF23 was unsuppressed suggestive of oncogenic osteomalacia. Diagnostic studies showed increase uptake in multiple bones. Localization with MRI of paranasal sinuses revealed a sinonasal mass with concurrent uptake in the same area on the octreotide scan. Surgical resection of the sinonasal mass was consistent with the glomus tumor. The patient improved both clinically and biochemically postoperatively. Along with the case of oncogenic osteomalacia secondary to a glomus tumor, we have also discussed in detail the recent development in the diagnosis and management of oncogenic osteomalacia. Learning points Tumor-induced osteomalacia is a rare cause of osteomalacia caused by the secretion of FGF23 from mesenchymal tumors. Mesenchymal tumors causing TIO are often difficult to localize and treat. Resection of the tumor can result in complete resolution of biochemical and clinical manifestations in a very short span of time. Glomus tumor can lead to tumor induced osteomalacia and should be surgically treated.