Phosphaturic mesenchymal tumors (PMTs) are rare tumors that can cause tumor-induced osteomalacia (TIO) through overproduction of FGF23, a peptide hormone that causes renal phosphate wasting and reduced osteoblastic activity. The diagnosis of PMTs can be difficult to make as the presenting symptoms are non-specific. Although PMT is a rare entity, most cases are benign in nature, not requiring further intervention after surgery, as resection is typically curative. Here, we present a unique case of malignant PMT with de novo liver metastasis in a female patient who presented with TIO and underwent surgical resection of her primary lesion with subsequent regression of her liver metastasis. Moreover, we analyze a review of literature and discuss the importance of a timely diagnosis of this rare phenomenon. It is encouraged that providers strongly consider a diagnosis of PMT in patients with otherwise unexplained bone pain, fatigue, weakness, especially if accompanied with hypophosphatemia. Further studies are also warranted to identify prognostic factors that predict a PMT's malignant potential as they may help identify possible therapeutic targets.
Keywords: FGF23; FN1-FGF1 fusion protein; osteomalacia; paraneoplastic syndrome; phosphaturic mesenchymal tumor; tumor induced.
Phosphaturic mesenchymal tumor with spread to the liver: A case report and literature review Phosphaturic mesenchymal tumors (PMTs) are rare tumors that can cause bone loss through the excess production of a signal named FGF23. This hormone causes the kidneys to lose phosphate and reduces the body’s ability to build new bone. PMTs are incredibly rare and difficult to diagnose especially since the presenting symptoms can be seen in several different diseases. Although PMT is rare, most cases are benign, only requiring surgery. We are presenting a unique case of a patient who presented with PMT in her right thigh and had evidence that the disease spread to her liver. Our patient underwent surgical resection of her thigh lesion and subsequently had improvement of her liver lesion. In our study, we analyze a review of literature and discuss the importance of a timely diagnosis of this rare phenomenon. It is encouraged that providers strongly consider a diagnosis of PMT in patients with otherwise unexplained bone pain, fatigue, weakness, especially if accompanied by low phosphate levels. Further studies are also warranted to identify prognostic factors that predict a PMT’s malignant potential as they may help identify possible therapeutic targets.
© The Author(s), 2024.