Phosphaturic Mesenchymal Tumor: 2 New Oral Cases and Review of 53 Cases in the Head and Neck

Abstract

Phosphaturic mesenchymal tumor (PMT) is a rare neoplasm that secretes fibroblast growth factor-23 (FGF-23) and causes oncogenic osteomalacia. It occurs in adults with equal gender distribution and the most common location is the lower extremities, followed by the head and neck. Besides osteomalacia, the clinical presentation includes bone pain and multiple bone fractures. Microscopic features consist of spindle cells, multinucleated giant cells, and calcifications embedded in a chondromyxoid matrix. Laboratory findings indicate normal calcium and parathyroid levels, hypophosphatemia, and increased levels of FGF-23 that usually revert to normal after surgical removal. Due to its rarity, the purpose of the study was to report 2 new oral cases of PMT and to review the literature in the head and neck. The first case occurred in the gingiva and had been present for 6 years. The second case was a recurrence of a previously diagnosed PMT in the right mandible that metastasized to the lung and soft tissue. The literature review included 53 cases in the head and neck. There was a predilection for extra-oral sites (76 %) compared to intra-oral sites (24 %) with paranasal sinuses considered the most common location (38 %) followed by the mandible (15 %). There were 9 recurrences that included 3 malignant cases indicating a potentially aggressive tumor. Due to the indeterminate biological behavior of PMT and its rarity, a comprehensive evaluation of medical, laboratory, radiographic, and histological findings are crucial for a definitive diagnosis and treatment.

Nonremission and Recurrent Tumor-Induced Osteomalacia: A Retrospective Study

“…Among each tumor location, head/neck tumors exerted the highest recovery rate, whereas spine tumors were most likely to be refractory. More than 70 cases in the head/neck have been reported in addition to the cases reported from our institute, and only 10 cases among them were refractory . Although this rate is higher than ours, it is plausible that TIO tumors in the head/neck have a favorable outcome.…”

Tumor‐induced hypophosphatemic osteomalacia caused by a mesenchymal tumor of the mandible managed by a segmental mandibulectomy and microvascular reconstruction with a free fibula flap

“…Of those, only 55 cases have been reported in the head and neck region (43 in extra‐oral sites, with the paranasal sinuses being the most common) . Twelve of these reported cases were noted in intraoral sites, with the mandible being the most common, followed by the floor of the mouth, tongue, gingiva, and maxilla . Involvement of the mandible is exceptionally rare, with only eight reported cases in the literature to date …”

“…Late recurrence due to metastatic disease is rare (<5%) but is also a possibility . Of the 55 cases of head and neck TIO reported in the medical literature, 9 had recurrence . Of the eight cases of mandibular TIO, six were treated with surgery .…”

“…After considering several therapeutic options, we elected to surgically resect the tumor using a segmental mandibulectomy, a procedure that, to our knowledge, has not been previously used for this disorder . Segmental mandibulectomy ensures a complete surgical resection with wide margins.…”

Glomus tumor as a cause of oncogenic osteomalacia

“…In the head and neck area the extra-oral sites are more common than the intra-oral sites. The most common location in the extra oral sits is paranasal sinuses followed by the mandible (17). Plasma intact PTH 102 ng/ml 8.0-74.0 ng/ml © C I C E d i z i o n i I n t e r n a z i o n a l i…”