A Case of Phosphaturic Mesenchymal Tumor

Phosphaturic mesenchymal tumors (PMTs) are rare and found to be commonly associated with phosphaturia and oncogenic osteomalacia. They commonly affect middle-aged adults and are located mostly in the extremities. Most of them are benign with only a few metastatic cases described in the literature. PMT-mixed connective tissue (PMTMCT) type is the most common PMT. Though most cases of PMTMCT have been associated with oncogenic osteomalacia and phosphaturia, there have been many reports of nonphosphaturic variants of this tumor with no clinical or laboratory evidence of tumor-induced osteomalacia. However, most of these nonphosphaturic variants previously described were not metastatic. We describe an unusual case of PMTMCT with widespread osseous metastases and without evidence of tumor-induced osteomalacia or phosphaturia.