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Phosphaturic mesenchymal tumor (PMT): exceptionally rare disease, yet crucial not to miss

Phosphaturic mesenchymal tumors (PMTs) are very rare tumors which are frequently associated with Tumor Induced Osteomalacia (TIO), a paraneoplastic syndrome that manifests as renal phosphate wasting. The tumor cells produce a peptide hormone-like substance known as fibroblast growth factor 23 (FGF23...

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Autores principales: Ghorbani-Aghbolaghi, Amir, Darrow, Morgan Angus, Wang, Tao
Formato: Online Artículo Texto
Lenguaje:English
Publicado: São Paulo, SP: Universidade de São Paulo, Hospital Universitário 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5634432/
https://www.ncbi.nlm.nih.gov/pubmed/29043208
http://dx.doi.org/10.4322/acr.2017.031
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author Ghorbani-Aghbolaghi, Amir
Darrow, Morgan Angus
Wang, Tao
author_facet Ghorbani-Aghbolaghi, Amir
Darrow, Morgan Angus
Wang, Tao
author_sort Ghorbani-Aghbolaghi, Amir
collection PubMed
description Phosphaturic mesenchymal tumors (PMTs) are very rare tumors which are frequently associated with Tumor Induced Osteomalacia (TIO), a paraneoplastic syndrome that manifests as renal phosphate wasting. The tumor cells produce a peptide hormone-like substance known as fibroblast growth factor 23 (FGF23), a physiologic regulator of phosphate levels. FGF23 decreases proximal tubule reabsorption of phosphates and inhibits 1-α-hydroxylase, which reduces levels of 1-α, 25-dihydroxyvitamine D3. Thus, overexpression of FGF23 by the tumor cells leads to increased excretion of phosphate in the urine, mobilization of calcium and phosphate from bones, and the reduction of osteoblastic activity, ultimately resulting in widespread osteomalacia. Patients typically present with gradual muscular weakness and diffuse bone pain from pathologic fractures. The diagnosis is often delayed due to the non-specific nature of the symptoms and lack of clinical suspicion. While serum phosphorus and FGF23 testing can assist in making a clinical diagnosis of PMT, the responsible tumor is often difficult to locate. The pathologic diagnosis is often missed due to the rarity of PMTs and histologic overlap with other mesenchymal neoplasms. While patients can experience severe disabilities without treatment, excision is typically curative and results in a dramatic reversal of symptoms. Histologically, PMT has a variable appearance and can resemble other low grade mesenchymal tumors. Even though very few cases of PMT have been reported in the world literature, it is very important to consider this diagnosis in all patients with hypophosphatemic osteomalacia. Here we present a patient who suffered for almost 5 years without a diagnosis. Ultimately, the PMT was located on a 68Ga-DOTA TATE PET/CT scan and subsequently confirmed by histologic and immunohistologic study. Interestingly, strong positivity for FGFR1 by IHC might be related to the recently described FN1-FGFR1 fusion. Upon surgical removal, the patient’s phosphate and FGF23 levels returned to normal and the patient’s symptoms resolved.
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spelling pubmed-56344322017-10-17 Phosphaturic mesenchymal tumor (PMT): exceptionally rare disease, yet crucial not to miss Ghorbani-Aghbolaghi, Amir Darrow, Morgan Angus Wang, Tao Autops Case Rep Article / Clinical Case Report Phosphaturic mesenchymal tumors (PMTs) are very rare tumors which are frequently associated with Tumor Induced Osteomalacia (TIO), a paraneoplastic syndrome that manifests as renal phosphate wasting. The tumor cells produce a peptide hormone-like substance known as fibroblast growth factor 23 (FGF23), a physiologic regulator of phosphate levels. FGF23 decreases proximal tubule reabsorption of phosphates and inhibits 1-α-hydroxylase, which reduces levels of 1-α, 25-dihydroxyvitamine D3. Thus, overexpression of FGF23 by the tumor cells leads to increased excretion of phosphate in the urine, mobilization of calcium and phosphate from bones, and the reduction of osteoblastic activity, ultimately resulting in widespread osteomalacia. Patients typically present with gradual muscular weakness and diffuse bone pain from pathologic fractures. The diagnosis is often delayed due to the non-specific nature of the symptoms and lack of clinical suspicion. While serum phosphorus and FGF23 testing can assist in making a clinical diagnosis of PMT, the responsible tumor is often difficult to locate. The pathologic diagnosis is often missed due to the rarity of PMTs and histologic overlap with other mesenchymal neoplasms. While patients can experience severe disabilities without treatment, excision is typically curative and results in a dramatic reversal of symptoms. Histologically, PMT has a variable appearance and can resemble other low grade mesenchymal tumors. Even though very few cases of PMT have been reported in the world literature, it is very important to consider this diagnosis in all patients with hypophosphatemic osteomalacia. Here we present a patient who suffered for almost 5 years without a diagnosis. Ultimately, the PMT was located on a 68Ga-DOTA TATE PET/CT scan and subsequently confirmed by histologic and immunohistologic study. Interestingly, strong positivity for FGFR1 by IHC might be related to the recently described FN1-FGFR1 fusion. Upon surgical removal, the patient’s phosphate and FGF23 levels returned to normal and the patient’s symptoms resolved. São Paulo, SP: Universidade de São Paulo, Hospital Universitário 2017-09-30 /pmc/articles/PMC5634432/ /pubmed/29043208 http://dx.doi.org/10.4322/acr.2017.031 Text en Autopsy and Case Reports. ISSN 2236-1960. Copyright © 2017. http://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium provided the article is properly cited.
spellingShingle Article / Clinical Case Report
Ghorbani-Aghbolaghi, Amir
Darrow, Morgan Angus
Wang, Tao
Phosphaturic mesenchymal tumor (PMT): exceptionally rare disease, yet crucial not to miss
title Phosphaturic mesenchymal tumor (PMT): exceptionally rare disease, yet crucial not to miss
title_full Phosphaturic mesenchymal tumor (PMT): exceptionally rare disease, yet crucial not to miss
title_fullStr Phosphaturic mesenchymal tumor (PMT): exceptionally rare disease, yet crucial not to miss
title_full_unstemmed Phosphaturic mesenchymal tumor (PMT): exceptionally rare disease, yet crucial not to miss
title_short Phosphaturic mesenchymal tumor (PMT): exceptionally rare disease, yet crucial not to miss
title_sort phosphaturic mesenchymal tumor (pmt): exceptionally rare disease, yet crucial not to miss
topic Article / Clinical Case Report
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5634432/
https://www.ncbi.nlm.nih.gov/pubmed/29043208
http://dx.doi.org/10.4322/acr.2017.031
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