Phosphaturic mesenchymal tumor with symptoms related to osteomalacia that appeared one year after tumorectomy.

A 45-year-old man was admitted to our hospital because of bone pain and hypophosphatemia. He had undergone surgery 2 years previously for a "benign unclassified mesenchymal tumor" in the skull, but there were no clinical symptoms related to osteomalacia. His laboratory examination revealed low serum phosphate, high alkaline phosphatase, and normal calcium levels. The diagnosis of tumor-induced osteomalacia due to phosphaturic mesenchymal tumor mixed connective tissue variant (PMTMCT) was made by re-examining the pathologic specimens. Oral supplementation with phosphate and 1-25-dihydroxyvitamin D relieved his clinical symptoms and laboratory values returned to normal. However, subcutaneous administration of octreotide had no clinical effect. Clinicians and pathologists should be aware of the existence of PMTMCT especially nonphosphaturic or asymptomatic variants of this disorder.

Phosphaturic mesenchymal tumor: a case report.

Osteomalacia induced by tumor is a rare phenomenon in which the resection of tumor is followed by dramatic amelioration of clinical signs and symptoms. We hereby report a case of a 66 years old male who presented with features of osteomalacia in which the characteristic clinical presentation was associated with the phosphaturic mesenchymal tumor, mixed connective tissue variant. The case is reported for its rarity.

Phosphaturic mesenchymal tumor-induced rickets.

We describe two prepubertal girls with oncogenic rickets. The first patient, 9 years of age, presented with recent-onset lower-extremity pain. The second girl, presented at 4 years of age following a 9-month period of muscle weakness, bone pain, and poor linear growth. Laboratory analyses in both patients revealed hypophosphatemia and hyperphosphaturia; elevated circulating alkaline phosphatase activity was present in one of them. Radiographic evidence of a generalized rachitic process was evident in both cases. Computerized tomography of the paranasal sinuses and facial bones in patient 1 revealed a small lesion eroding through the inner table of the left mandibular ramus. Microscopic examination of this mass revealed a spindle cell neoplasm with chondroid material, dystrophic calcification, and both osteoclast-like and fibroblast-like cells. Prominent vascularity and marked atypia were present. These features are consistent with a phosphaturic mesenchymal tumor of the mixed connective tissue variant. In the second patient, computerized tomography revealed a lytic lesion located in the right proximal tibia, with histologic features consistent with a phosphaturic mesenchymal tumor of the nonossifying fibroma-like variant. Resection of each tumor resulted in rapid correction of the phosphaturia and healing of the rachitic abnormalities. A careful search for small or occult tumors should be carried out in cases of acquired phosphaturic rickets.

Oncogenic osteomalacia associated with a meningeal phosphaturic mesenchymal tumor. Case report.

A 60-year-old woman suffered from hypophosphatemic osteomalacia secondary to a frontal intracranial tumor. Oral administration of phosphate and 1-alpha-hydroxyvitamin D3 provided only temporary symptomatic relief. A computerized tomography (CT) scan of the patient's head revealed a large subfrontal tumor attached to the dura. Following removal of the tumor, the patient's hypophosphatemia subsided; her level of 1,25-dihydroxyvitamin D3, which was undetectable preoperatively, returned to normal, and she had symptomatic improvement. Three years later, decreasing levels of phosphate and 1,25-dihydroxyvitamin D3 indicated tumor recurrence, before it was detected by CT scan. Histological examination of the tumor provided the diagnosis of "mixed connective tissue variant of phosphaturic mesenchymal tumor." The characteristic histological features of this relatively rare entity are discussed. This is the first report of a surgically treated intracranial phosphaturic mesenchymal tumor that caused oncogenic osteomalacia.