Oncogenic Osteomalacia Associated with Phosphaturic Mesenchymal Tumor of the Knee: Case Presentation and Review of the Literature


Oncogenic osteomalacia (OOM) is an uncommon metabolic and bone disease caused by fibroblast growth factor 23 (FGF23), a phosphaturic factor produced by phosphaturic mesenchymal tumors (mixed connective tissue variant, PMTMCTV) characterized by phosphate leakage from kidneys and subsequent hypophosphatemia. In this paper, we present the case of a patient, 42-year-old woman affected by left side limp and pain involving lumbar spine, pelvis and hip joints, referred to the Rheumatology Department of our Hospital for the treatment of a suspected sero-negative spondilo-arthritis. During hospitalization patient began an immuno-suppressive therapy with TNF-alpha inhibitors associated with Pamidornate, Indometacin, Esomeprazole and vitamin D3. Nevertheless pain did not decrease and a new examination found a worst hypophosphatemia (1 mg/dl) with normal Ca and PTH’s plasma values. During the same check-up a painful bulge on the anterior part of the right knee was observed and the Magnetic Resonance Imaging scan revealed an ovular solid lesion in the soft tissue closed to the upper part of the patella. Histological analysis identified the lesion as a PMTMCTV. After surgical removal patient got complete recovery. We will discuss about diagnostic evaluation, differential diagnosis and treatment.

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E. Vecchini, T. Maluta, M. Bondi, F. Perusi, S. Dall’Oglio and B. Magnan, "Oncogenic Osteomalacia Associated with Phosphaturic Mesenchymal Tumor of the Knee: Case Presentation and Review of the Literature," International Journal of Clinical Medicine, Vol. 4 No. 7A, 2013, pp. 24-27. doi: 10.4236/ijcm.2013.47A1004.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] M. J. Econs and M. K. Drezner, “Tumor-Induced Osteomalacia—Unveiling a New Hormone,” The New England Journal of Medicine, Vol. 330, No. 23, 1994, pp. 16791681. doi:10.1056/NEJM199406093302310
[2] A. L. Folpe, J. C. Fanburg-Smith, S. D. Billings, et al., “Most Osteomalacia-Associated Mesenchymal Tumors Are a Single Histopathologic Entity: An Analysis of 32 Cases and a Comprehensive Review of the Literature,” The American Journal of Surgical Pathology, Vol. 28, No. 1, 2004, pp. 1-30. doi:10.1097/00000478-200401000-00001
[3] R. Kumar, “Tumor-Induced Osteomalacia and the Regulation of Phosphate Homeostasis,” Bone, Vol. 27, No. 3, 2000, pp. 333-338. doi:10.1016/S8756-3282(00)00334-3
[4] M. K. Drezner, “Tumor-Induced Osteomalacia,” Reviews in Endocrine and Metabolic Disorders, Vol. 2, No. 2, 2001, pp. 175-186. doi:10.1023/A:1010006811394
[5] S. M. Jan de Beur, E. A. Streeten, A. C. Civelek, E. F. McCarthy, L. Uribe, S. J. Marx, O. Onobrakpeya, L. G. Raisz, N. B. Watts, M. Sharon and M. A. Levine, “Localisation of Mesenchymal Tumors by Somatostatin Receptor Imaging,” Lancet, Vol. 359, No. 9308, 2002, pp. 761763. doi:10.1016/S0140-6736(02)07846-7
[6] A. Szumera-Cieckiewicz, K. Ptaszyński, A. Pawenas and P. Rutkowski, “Oncogenic Osteomalacia Associated with Phosphaturic Mesenchymal Tumour, Mixed Connective Tissue Type of the Knee,” Polish Journal of Pathology, Vol. 60, No. 4, 2009, pp. 193-198.
[7] F. K. Hu, F. Yuan, C. Y. Jiang, D. W. Lv, B. B. Mao, Q. Zhang, Z. Q. Yuan and Y. Wang, “Tumor-Induced Osteomalacia with Elevated Fibroblast Growth Factor 23: A Case of Phosphaturic Mesenchymal Tumor Mixed with Connective Tissue Variants and Review of the Literature,” Chinese Journal of Cancer, Vol. 30, No. 11, 2011, pp. 794-804. doi:10.5732/cjc.011.10013
[8] M. Akhter, P. A. Sugrue, R. Bains and Y. A. Khavkin, “Oncogenic Osteomalacia of the Cervical Spine: A Rare Case of Curative Resection and Reconstruction,” Journal of Neurosurgery: Spine, Vol. 14, No. 4, 2011, pp. 453456. doi:10.3171/2010.11.SPINE09750
[9] N. R. Peterson, D. J. Summerlin and S. R. Cordes, “Multiple Phosphaturic Mesenchymal Tumors Associated with Oncogenic Osteomalacia: Case Report and Review of the Literature,” Ear, Nose & Throat Journal, Vol. 89, No. 6, 2010, pp. E11-E15.
[10] P. Suryawanshi, M. Agarwal, R. Dhake, S. Desai, B. Rekhi, K. B. Reddy and N. A. Jambhekar, “Phosphaturic Mesenchymal Tumor with Chondromyxoid Fibroma-Like Feature: An Unusual Morphological Appearance,” Skeletal Radiology, Vol. 40, No. 11, 2011, pp. 1481-1485. doi:10.1007/s00256-011-1159-6
[11] S. Fukumoto, Y. Takeuchi, A. Nagano and T. Fujita, “Diagnostic Utility of Magnetic Resonance Imaging Skeletal Survey in a Patient with Oncogenic Osteomalacia,” Bone, Vol. 25, No. 3, 1999, pp. 375-377. doi:10.1016/S8756-3282(99)00170-2
[12] J. L. Dupond, H. Mahammedi, D. Prie, F. Collin, H. Gil, O. Blagosklonov, B. Ricbourg, N. Meaux-Ruault and B. Kantelip, “Oncogenic Osteomalacia: Diagnostic Importance of Fibroblast Growth Factor 23 and F-18 Fluorodeoxyglucose PET/ct Scan for the Diagnosis and Follow-Up in One Case,” Bone, Vol. 36, No. 3, 2005, pp. 375-378. doi:10.1016/j.bone.2005.01.001
[13] E. Hesse, E. Moessinger, H. Rosenthal, F. Laenger, G. Brabant, T. Petrich, K. F. Gratz and L. Bastian, “Oncogenic Osteomalacia: Exact Tumor Localization by CoRegistration of Positron Emission and Computed Tomography,” Journal of Bone and Mineral Research, Vol. 22, No. 1, 2007, pp. 158-162. doi:10.1359/jbmr.060909
[14] K. B. Jonsson, R. Zahradnik, T. Larsson, K. E. White, T. Sugimoto, Y. Imanishi, T. Yamamoto, G. Hampson, H. Koshiyama, O. Ljunggren, K. Oba, I. M. Yang, A. Miyauchi, M. J. Econs, J. Lavigne and H. Juppner, “Fibroblast Growth Factor 23 in Oncogenic Osteomalacia and X-Linked Hypophosphatemia,” New England Journal of Medicine, Vol. 348, No. 17, 2003, pp. 1656-1663. doi:10.1056/NEJMoa020881

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