ACTA ENDOCRINOLOGICA (BUC)

Background. Phosphaturic mesenchymal tumor (PMT) is a recently described concept\r\nunifying the mesenchymal tumor associated with oncogenic osteomalacia. Most of the cases of\r\nPMT occur in the extremities and appendicular skeleton. PMT occurring in the paranasal\r\nsinuses is extremely rare with only a few cases reported in the available literature.\r\nCase. A 51-year-old man presented with a long history of bone pains. Biochemical\r\nand radiologic investigations, including skeletal survey showed features of osteomalacia.\r\nPositron emission tomography (PET) scan showed a small tumor in the left nasal cavity,\r\nethmoid and sphenoid sinuses. Histopathological examination of the excised tumor showed\r\nfeatures of a phosphaturic mesenchymal tumor- mixed connective tissue variant. Excision\r\nof the tumor was associated with marked improvement in the biochemical parameters and\r\nremarkable clinical relief.\r\nConclusion. Phosphaturic mesenchymal tumor is a rare cause of osteomalacia and is\r\nusually associated with small tumors, which escape detection for long periods. Its occurrence in\r\nthe paranasal sinuses needs to be kept in mind and evaluated to allow for timely detection of the\r\ntumor with subsequent surgical excision and clinico-biochemical relief.