Published: 2019-08-28

Phosphaturic mesenchymal tumor

Robin George Cheereth, Rogers P. Augustine, Highness Tholakkara Nazar


Phosphaturic mesenchymal tumors (PMTs) are very unusual tumors, commonly associated with tumor induced osteomalacia (TIO). The tumor cells produce a peptide hormone-like substance known as fibroblast growth factor 23 (FGF23), which regulates phosphate levels. When FGF23 is over expressed by the tumor cells it leads to phosphaturia, which inturn causes mobilization of calcium and phosphate from bones, and decreased osteoblastic activity, which finally leads to severe osteomalacia. Usual presentation of PMT will be gradual muscular weakness and diffuse bone pain from pathologic fractures. The majority of PMTs are benign, malignant PMTs are extremely rare, but exist. However, very rarely PMT present without phosphaturia and TIO i.e., the nonphosphaturic variant. The challenge in diagnosis of PMT is due to the vague nature of the symptoms and lack of clinical suspicion. The diagnosis is often missed due to the rarity of PMTs. The usual location for PMT involves the extremities followed by head and neck sites. We report a case of a 37 year old male who presented to the outpatient department with a swelling in the left parotid region. He had no associated symptoms. CT scan showed a well-defined heterogeneous mass measuring 2.3 × 2.0 cm with calcification and soft tissue density seen superficially in the left pre auricular region. Per operatively the tumor was found to be intramuscular, embedded in the left masseter muscle. The final histopathology report was confirmative of phosphaturic mesenchymal tumor.


Phosphaturic mesenchymal tumors, Tumor induced osteomalacia, Nonphosphaturic

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Pal R, Bhadada SK, Shingare A, Bhansali A, Kamalanathan S, Chadha M, et al. Tumor-induced osteomalacia: experience from three tertiary care centres in India. Endocr Connect. 2019;pii:EC-18-0552.R1.

Zuo QY, Wang H, Li W, Niu XH, Huang YH, Chen J, et al. Treatment and outcomes of tumor-induced osteomalacia associated with phosphaturic mesenchymal tumors: retrospective review of 12 patients. BMC Musculoskelet Disord. 2017;18(1):403.

Yavropoulou MP, Poulios C, Foroulis C, Tournis S, Hytiroglou P, Kotsa K, et al. Distant lung metastases caused by a histologically benign phosphaturic mesenchymal tumor. Endocrinol Diabetes Metab Case Rep. 2018;2018:18-23.

Sent-Doux KN, Mackinnon C, Lee JC, Folpe AL, Habeeb O. Phosphaturic mesenchymal tumor without osteomalacia: additional confirmation of the “nonphosphaturic” variant, with emphasis on the roles of FGF23 chromogenic in situ hybridization and FN1-FGFR1 fluorescence in situ hybridization. Hum Pathol. 2018;80:94-8.

Agaimy A, Michal M, Chiosea S, Petersson F, Hadravsky L, Kristiansen G, et al. Phosphaturic Mesenchymal Tumors Clinicopathologic, Immuno-histochemical and Molecular Analysis of 22 Cases Expanding their Morphologic and Immunophenotypic Spectrum. Am J Surg Pathol. 2017;41(10):1371-80.

Wu H, Bui MM, Zhou L, Li D, Zhang H, Zhong D. Phosphaturic mesenchymal tumor with an admixture of epithelial and mesenchymal elements in the jaws: clinicopathological and immune-histochemical analysis of 22 cases with literature review. Mod Pathol. 2019;32(2):189-204.

Qari H, Hamao-Sakamoto A, Fuselier C, Cheng YS, Kessler H, Wright J. Phosphaturic Mesenchymal Tumor: 2 New Oral Cases and Review of 53 Cases in the Head and Neck. Head and Neck Pathol. 2016;10:192–200.

Pelo S, Gasparini G, Garagiola U, D’Amato G, Saponaro G, Doneddu P, et al. Phosphaturic mesenchymal tumor, an unusual localization in head and neck. J Surg Case Rep. 2018;2018(5):rjy091.

Folpe AL, Fanburg-Smith JC, Billings SD, Bisceglia M, Bertoni F, Cho JY, et al. Most Osteomalacia-associated Mesenchymal Tumors Are a Single Histopathologic Entity: An Analysis of 32 Cases and a Comprehensive Review of the Literature Am J Surg Pathol. 2004;28(1):1-30.

Ghorbani-Aghbolaghia A, Darrowa MA, Wanga T. Phosphaturic mesenchymal tumor (PMT): exceptionally rare disease, yet crucial not to miss. Autops Case Rep (São Paulo). 2017;7(3):32-7.

Qiu S, Cao LL, Qiu Y, Yan P, Li Z, Du J, et al. Malignant phosphaturic mesenchymal tumor with pulmonary metastasis. Medicine. 2017;96:17(e6750).

Boland JM, Tebben PJ, Folpe AL. Phosphaturic mesenchymal tumors: what an endocrinologist should know? J Endocrinol Invest. 2018;41(10):1173-84.

Honda R, Kawabata Y, Ito S, Kikuchi F. Phosphaturic mesenchymal tumor, mixed connective tissue type, non-phosphaturic variant: Report of a case and reviewof 32 cases from the Japanese published work. J Dermatol. 2014;41:845–9.

Yamada Y, Kinoshita I, Kenichi K, Yamamoto H, Iwasaki T, Otsuka H, et al. Histopathological and Genetic Review of Phosphaturic Mesenchymal Tumours, Mixed Connective Tissue Variant. Histopathology. 2018;72(3):460-71.

William J, Laskin W, Nayar R, De Frias D. Diagnosis of PhosphaturicMesenchymal Tumor (MixedConnective Tissue Type) by Cytopathology. Diagn Cytopathol. 2012;40 Suppl 2:E109-13.

Woo VL, Landesberg R, Imel EA, Singer SR, Folpe AL, Econs MJ, et al. Phosphaturic mesenchymal tumor, mixed connective tissue variant, of the mandible: report of a case and review of the literature. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009;108(6):925-32.

Kobayashi H, Makise N, Ushiku T, Nobuaki Ito, Koga M, Shinoda Y, et al. Infiltrative nature of tumor-induced osteomalacia lesions in bone: Correlation between radiological and histopathological features. J Orthop Sci. 2019;pii:S0949-2658(19):30053-3.

Shi Z, Deng Y, Li X, Li Y, Cao D, Coossa VS. CT and MR imaging features in phosphaturic mesenchymal tumor-mixed connective tissue: A case report. Oncol Lett. 2018;15(4):4970-8.

Broski SM, Wenger DE, Folpe AL. Imaging features of phoshaturic mesenchymal tumors. Skeletal Radiol. 2019;48(1):119-27.

Lee JY, Park HS, Han S, Lim JK, Hong N, Park S, et al. Localization of Oncogenic Osteomalacia by Systemic Venous Sampling of Fibroblast Growth Factor 23. Yonsei Med J. 2017;58(5):981-7.

Xiao X, Sun X, Ni P, Huang Y, Xie T. Phosphaturic mesenchymal tumor and related wound problem. Medicine (Baltimore). 2018;97(40):e12507.

Walsh EM, Jacob J, Walsh EM, Jacob J, Lucas DR, Sargent EW. Phosphaturic Mesenchymal Tumor of the Cerebellopontine Angle. JAMA Otolaryngol Head Neck Surg. 2019;145(3):287-8.

Wasserman JK, Purgina B, Lai CK, Gravel D, Mahaffey A, Bell D, et al. Phosphaturic Mesenchymal Tumor Involving the Head and Neck: A Report of Five Cases with FGFR1 Fluorescence In Situ Hybridization Analysis. Head Neck Pathol. 2016;10(3):279-85.

Wang X, Gao J, Han S, Li Y. Spinal phosphaturic mesenchymal tumors: Case report and literature review. J Clin Neurosci. 2019;63:234-9.

Kurien R, Rupa V, Thomas M. Varied presentation of sinonasal phosphaturic mesenchymal tumor: report of a case series with follow-up. Eur Arch Otorhinolaryngol. 2019;276(6):1677-84.