PET/CT Localization of Phosphaturic Mesenchymal Neoplasm Causing Tumor-Induced Osteomalacia

Abstract

Tumor-induced osteomalacia (TIO), also known as oncogenic osteomalacia (OO), is a rare syndrome characterized by muscle and bone pain, osteomalacia, low serum 1,25-dihydroxy vitamin D, hypophosphatemia, and hyperphosphaturia. This syndrome is caused by a phosphaturic hormone-secreting mesenchymal neoplasm, which is usually benign but often occult. Since excision of the tumor is curative, preoperative tumor localization is essential. However, despite the many radiologic and scintigraphic imaging techniques available, such localization remains a challenge in many cases. We report a case of tumor-induced osteomalacia in which PET-CT successfully localized the occult mesenchymal neoplasm after multiple other imaging tests failed.

Case 33-2011

“…One of the most difficult features of the management of osteogenic osteomalacia can be localizing the offending tumor. The general approach to localization involves functional imaging (combined 18 F-fluorodeoxyglucose–positron-emission tomography and CT 18 or indium-111–labeled pentetreotide 19 or both 20 ), followed by anatomical imaging (CT or MRI or both) of suspicious areas that have been identified on functional imaging, as was done in this case. Selective venous sampling, also performed in this case, may be an important tool in cases in which more certainty is needed.…”

Using 18F-FDG PET/CT to Detect an Occult Mesenchymal Tumor Causing Oncogenic Osteomalacia

“…In many cases, CT and MRI are not contributory in diagnosing oncogenic osteomalacia [3] because this tumor is often small, grows slowly, and develops in unpredictable locations such as feet [17], mandibular ramus [18], and frontal bone [19]. Previous case reports suggested that 18 F-FDG PET/CT is a useful modality in detection of oncogenic tumors causing oncogenic osteomalacia [11][12][13][14][15]. In the present report, the mesenchymal tumor causing oncogenic osteomalacia was easily detected by 18 F-FDG PET/CT.…”

“…To the best of our knowledge, only a few case reports have evaluated the feasibility of 18 F-fluorodeoxyglucose positron emission tomography ( 18 F-FDG PET)/CT in detecting occult mesenchymal tumors in oncogenic osteomalacia [11][12][13][14][15]. Despite the benign nature of mesenchymal tumors, each case report indicated that the mesenchymal tumor associated with oncogenic osteomalacia exhibited relatively high 18 F-FDG uptake and was easily detected by 18 F-FDG PET/CT.…”

Oncogenic Osteomalacia Caused by Phosphaturie Mesenchymal Tumours in the Proximal and Shaft of the Tibia: A Case Report

“…Investigation tools include MRI, [13][14][15][16][17][18][19] octreotide scintigraphy, [20][21][22][23][24][25] 201 TI scintigraphy, 26 99m Tc-MIBI scintigraphy, 26,27 and F-18 FDG positron emission tomography (PET) [28][29][30] (Table). MRI is the investigation of choice owing to its high sensitivity.…”