phosphaturic mesenchymal tumors of the mixed connective tissue type
Phosphaturic mesenchymal tumors of the mixed connective tissue type (PMTMCT) are extremely rare, histologically distinctive neoplasms, which cause tumor-induced osteomalacia (TIO) in most cases through the elaboration of a phosphaturic hormone, fibroblast growth factor-23 (FGF23).
RT-PCR for FGF23 is a sensitive and specific means of confirming the diagnosis of PMTMCT both in patients with and without TIO. FGF23 gene expression was present in more than 90% of PMTMCT with known TIO, confirming the role of FGF23 in this syndrome.
Rare FGF23-negative PMTMCT with known TIO likely express other phosphaturic hormones (eg, frizzled-related protein 4).
Expression of FGF23 in 75% of histologically identical tumors without known TIO confirms the reproducibility of the diagnosis of PMTMCT, even in the absence of known phosphaturia.
Localization
sinonasal (#20216375#)
References
Sinonasal phosphaturic mesenchymal tumor (mixed connective tissue variant): report of 2 cases. Shelekhova KV, Kazakov DV, Michal M. Am J Surg Pathol. 2010 Apr;34(4):596-7. PMID: #20216375#
RT-PCR Analysis for FGF23 Using Paraffin Sections in the Diagnosis of Phosphaturic Mesenchymal Tumors With and Without Known Tumor Induced Osteomalacia. Bahrami A, Weiss SW, Montgomery E, Horvai AE, Jin L, Inwards CY, Folpe AL. Am J Surg Pathol. 2009 Jul 15. PMID: #19609206#