Oncogenic osteomalacia/phosphaturic mesenchymal tumor: clinical case and literature review

Phosphaturic mesenchymal tumor inducing development of phosphopenic osteomalacia is manifested as deformations and multiple fractures of the bones which decreases patients’ quality of life and leads to disability. Insufficient awareness about this pathology among doctors and absence of symptoms allowing its diagnosis cause late diagnosis of the disease despite application of up-to-date high-tech diagnostic methods. The optimal treatment of phosphaturic mesenchymal tumors is radical resection. However, strong connection of the tumor with the surrounding tissues and, in many cases, absence of a capsule or sclerosis (if located in the bones) complicate surgery leading to high recurrence rate. Radical resection of phosphaturic mesenchymal tumors is especially complicated in cases of localization in complex anatomical areas of the lower limbs.

The disease is characterized by long timespan between first clinical signs, diagnosis, and start of treatment (sometimes, several years). Diagnosis confirmation and visualization of the details of phosphaturic mesenchymal tumor requires magnetic resonance imaging. This method allows to examine connection between the tumor and surrounding tissues and the presence of a capsule. Magnetic resonance imaging also allows to accurately determine the area of surgical intervention. Radical tumor resection leads to normalization of blood and urine biochemistry in the span of several weeks. Restoration of bone density and muscle function requires 3–6 months after the operation.