title: Tumor-induced osteomalacia caused by a massive phosphaturic mesenchymal tumor of the acetabulum: A case report.
abstract: We report a case of tumor-induced osteomalacia (TIO) caused by a massive phosphaturic mesenchymal tumor (PMT) of the acetabulum. A 68-year-old woman presented with progressive bone pain of the rib cage, and polyarthralgia and back pain for 3 years. She was diagnosed with hypophosphatemic osteomalacia because laboratory testing was remarkable for low serum phosphorus and a low level of 1,25(OH)2 vitamin D. Three years later, her hip radiograph revealed an osteolytic lesion of the acetabulum. Magnetic resonance imaging of the acetabulum showed a massive lesion. Laboratory data showed hypophosphatemia and an elevated serum level of fibroblast growth factor 23 (FGF-23). Samples obtained with open biopsy showed a low-grade spindle cell neoplasm with FGF-23 positivity, identified by using immunohistochemical staining, confirming the diagnosis of a PMT mixed connective tissue variant. Curettage of the tumor was performed, and the defects were filled with bone allografts. The hip joint was reconstructed with total hip arthroplasty using a Muller support ring. To our knowledge, this report represents the first documented case of massive PMT of the acetabulum causing TIO.
authors.affiliation: a Department of Orthopaedic Surgery , Kyushu University Hospital , Fukuoka , Japan and.
authors.forename: Kimitaka
authors.initials: K
authors.lastname: Nakamura
authors.affiliation: a Department of Orthopaedic Surgery , Kyushu University Hospital , Fukuoka , Japan and.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Ohishi
authors.affiliation: a Department of Orthopaedic Surgery , Kyushu University Hospital , Fukuoka , Japan and.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Matsunobu
authors.affiliation: a Department of Orthopaedic Surgery , Kyushu University Hospital , Fukuoka , Japan and.
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Nakashima
authors.affiliation: a Department of Orthopaedic Surgery , Kyushu University Hospital , Fukuoka , Japan and.
authors.forename: Akio
authors.initials: A
authors.lastname: Sakamoto
authors.affiliation: b Department of Anatomic Pathology, Graduate School of Medical Sciences , Kyushu University , Fukuoka , Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Maekawa
authors.affiliation: b Department of Anatomic Pathology, Graduate School of Medical Sciences , Kyushu University , Fukuoka , Japan.
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Oda
authors.affiliation: a Department of Orthopaedic Surgery , Kyushu University Hospital , Fukuoka , Japan and.
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
mesh_terms: D000077:Acetabulum / Q000473:pathology*; D000368:Aged; D005260:Female; D000089703:Fibroblast Growth Factor-23; D006801:Humans; D008637:Mesenchymoma / Q000150:complications*; D009372:Neoplasms, Connective Tissue / Q000209:etiology / Q000473:pathology*; D010018:Osteomalacia; D010257:Paraneoplastic Syndromes
keywords: Phosphaturic mesenchymal tumor; Total hip arthroplasty; Tumor-indued osteomalacia