West African Journal of Radiology

: 2020  |  Volume : 27  |  Issue : 1  |  Page : 72--74

Tumor-induced osteomalacia as a paraneoplastic syndrome of a sinonasal neoplasm in Indian female

Punit Pushkar Mahajan, Nirav Thaker, Sunila Jaggi, Inder Talwar 
 Department of Radiology, Bombay Hospital Institute of Medical Sciences, Mumbai, Maharashtra, India

Correspondence Address:
Dr. Punit Pushkar Mahajan
Prathamesh Vaibhav Tower, Flat 303, Third Floor, Tagore Nagar, Vikhroli East, Mumbai . 400 083, Maharashtra


A rare case of oncogenic osteomalacia as a paraneoplastic syndrome of a sinonasal neoplasm detected incidentally on a positron emission tomography-computed tomography scan performed to find the cause of multiple axial and appendicular skeletal fractures. The neoplasm was later proven to be a hemangiopericytoma on histopathology with complete reversal of clinical symptoms, biochemical abnormalities, and decreased bone density on the postoperative follow-up.

How to cite this article:
Mahajan PP, Thaker N, Jaggi S, Talwar I. Tumor-induced osteomalacia as a paraneoplastic syndrome of a sinonasal neoplasm in Indian female.West Afr J Radiol 2020;27:72-74

How to cite this URL:
Mahajan PP, Thaker N, Jaggi S, Talwar I. Tumor-induced osteomalacia as a paraneoplastic syndrome of a sinonasal neoplasm in Indian female. West Afr J Radiol [serial online] 2020 [cited 2023 Mar 29 ];27:72-74
Available from: https://www.wajradiology.org/text.asp?2020/27/1/72/280599

Full Text


Oncogenic osteomalacia, also called tumor-induced osteomalacia, is characterized by markedly reduced serum phosphate and renal phosphate wasting, leading to bone pain and muscle weakness. It is usually caused by benign mesenchymal tumors such as fibromas, hemangiopericytomas, and giant cell tumor. Humoral basis of the disease is proved on the basis of improvement in the clinical features and biochemical abnormalities postsurgical excision.

 Case Report

A 48-year-old premenopausal female with no known clinical comorbidities presented to us with a 5-year long history of generalized weakness, back pain not radiating to any extremity, or neurogenic claudication with difficulty in walking. Plain radiographs of the spine and hips performed were suggestive of decreased bone density and bilateral ribs and femoral neck fractures with vertebral end-plate compression fractures. Serum phosphorus and Vitamin D levels were low with normal serum calcium and elevated Erythrocyte sedimentation rate (ESR). All these findings favored the diagnosis of osteomalacia which did not improve after Vitamin D and calcium supplements. Therefore, a positron emission tomography-computed tomography (PET-CT) scan was advised to rule out the remote possibility of an oncogenic cause of multiple axial and appendicular skeletal fractures. The PET-CT scan revealed mildly displaced fractures of the pubic rami, femoral necks (coxa vara deformity), coracoid processes of scapulae and bilateral ribs. Sacral insufficiency fractures and compression of lower dorsal vertebrae were also noted with end-plate sclerosis and biconcave-shaped vertebrae. None of these fractures showed significant 18-fluorodeoxyglucose (FDG) uptake on the PET study [Figure 1].{Figure 1}

However, a heterogeneously enhancing FDG avid (SUVmax 7.2) polypoidal soft tissue mass was seen in the nasoethmoid region attenuating the ethmoidal trabeculae [Figure 2], abutting the nasal septum and inferior turbinate appearing inseparable from the superior and middle turbinates, obstructing the ipsilateral osteomeatal unit, and reaching up to the posterior choana without extension into the pterygomaxillary fissure [Figure 3]a and [Figure 3]b. Rest of the scan did not reveal any metabolically active disease, and the mass was reported suspicious for a neoplasm. However, the patient did not give any history of nasal blockage or discharge.{Figure 2}{Figure 3}

Subsequently, the patient underwent a transnasal surgical excision of the mass under general anesthesia with moderate intraoperative bleeding. Histopathological examination of the resected mass revealed a mixture of spindle cells, abundant blood vessels, and metaplastic bony tissues likely a hemangiopericytoma [Figure 4].{Figure 4}

The patient improved clinically with respect to decreased bone pains and restoration of the biochemical abnormalities. Due to this dramatic recovery of the patient postsurgery, a diagnosis of oncogenic osteomalacia was confirmed.


Oncogenic osteomalacia is a rare cause of osteomalacia secondary to the presence of a mesenchymal tumor. The biochemical abnormality is thought to be due to release of fibroblast growth factor-23 (phosphatonin) from the tumor which inactivates the sodium–potassium pump in the proximal tubules of nephrons and results in decrease reabsorption of the phosphates and hydroxylation of 25-hydroxyvitamin D.[1],[2] The mean age of onset of symptom is 40 years and is seen in both sexes equally.[3] Osteomalacia is associated with the following laboratory abnormalities: (1) low serum phosphate levels, (2) lower limit of normal serum calcium level, (3) low-to-normal Vitamin D levels, and (4) phosphaturia.[4]

Magnetic resonance imaging, octreotide scintigraphy, and the PET-CT scan are the investigations normally performed for such patients.[5] However, in our case, physicians opted for a PET-CT scan. From treatment point of view, wide margin surgical resection is the best option available with preoperative angiography and sometimes embolization to reduce the vascularity of the neoplasm, if any.[3] In our case, for cost-effectiveness and in view of asymptomatic nature of disease, the surgeons directly opted for surgical intervention.

After searching the literature, only 10 cases of oncogenic osteomalacia due to a sinonasal neoplasm have been reported with all of them involving the ethmoid sinus.[6] Our case was a nasoethmoidal neoplasm with a benign asymptomatic course and probably the first case in the Indian population, which was detected on a PET-CT scan.

Other tumors such as hemangioma, angiofibroma, hemangioendothelioma, giant cell tumor, nonossifying fibroma, osteosarcoma, fibrosarcoma, angiosarcoma, and malignant fibrous histiocytoma are also known to be associated with oncogenic osteomalacia.[6]


When a patient presents with signs, symptoms, and biochemical investigations favoring osteomalacia which is not reversible on treatment, a paraneoplastic etiology should be suspected as documented in our case. Furthermore, when a patient presents with a nasal mass with symptoms of osteomalacia, oncogenic osteomalacia should be suspected.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.


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2Wilkins GE, Granleese S, Hegele RG, Holden J, Anderson DW, Bondy GP. Oncogenic osteomalacia: Evidence for a humoral phosphaturic factor. J Clin Endocrinol Metab 1995;80:1628-34.
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