Open AccessTumor-induced osteomalacia in association with PTEN-negative Cowden syndrome
Author(s) -
Jason A Berglund,
Rachel I Gafni,
Felasfa M. Wodajo,
Edward W. Cowen,
Diala ElMaouche,
Richard Chang,
C. C. Chen,
Lori C. Guthrie,
Alfredo Molinolo,
Michael T. Collins
Publication year - 2018
Publication title -
osteoporosis international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 170
eISSN - 1433-2965
pISSN - 0937-941X
DOI - 10.1007/s00198-017-4372-x
Subject(s) - medicine , fibroblast growth factor 23 , pten , hypophosphatemia , osteomalacia , cancer research , pathology , endocrinology , parathyroid hormone , osteoporosis , pi3k/akt/mtor pathway , biology , apoptosis , calcium , biochemistry
Tumor-induced osteomalacia (TIO) is a rare paraneoplastic condition in which phosphaturic mesenchymal tumors (PMTs) secrete high levels of fibroblast growth factor 23 (FGF23) into the circulation. This results in renal phosphate wasting, hypophosphatemia, muscle weakness, bone pain, and pathological fractures. Recent studies suggest that fibronectin-fibroblast growth factor receptor 1 (FN1-FGFR1) translocations may be a driver of tumorigenesis. We present a patient with TIO who also exhibited clinical findings suggestive of Cowden syndrome (CS), a rare autosomal dominant disorder characterized by numerous benign hamartomas, as well as an increased risk for multiple malignancies, such as thyroid cancer. While CS is a clinical diagnosis, most, but not all, harbor a mutation in the tumor suppressor gene PTEN. Genetic testing revealed a somatic FN1-FGFR1 translocation in the FGF23-producing tumor causing TIO; however, a germline PTEN mutation was not identified. To our knowledge, this is the first reported case of concurrent TIO and CS.