title: Phosphaturic mesenchymal tumor, nonphosphaturic variant, causing fatal pulmonary metastasis.
abstract: Phosphaturic mesenchymal tumors of the mixed connective tissue type (PMT-MCTs) are rare neoplasms, most of which are benign and cause tumor-induced osteomalacia because of overproduction of a phosphaturic hormone, fibroblast growth factor 23 (FGF23). This entity may have been unrecognized or misdiagnosed as other mesenchymal tumors, such as giant cell tumor, hemangiopericytoma, and osteosarcoma. Ten percent of these tumors, without phosphaturia, were diagnosed only by their histologic features. We report here the first case of malignant PMT-MCT, nonphosphaturic variant, resulting in fatal multiple lung metastases. Chondromyxoid matrix with "grungy" calcification, multinucleated giant cell proliferation, and expression of FGF23 mRNA (reverse transcription-polymerase chain reaction) and fibroblast growth factor 23 protein (immunohistochemistry) were seen in the primary and recurrent tumors of the right foot. The lung metastases showed flocculent calcification and FGF23 protein expression as well as giant cell proliferation. This unique case highlights the need for careful histologic assessment of PMT-MCTs, especially the nonphosphaturic variant, and the need for recognition of its rare malignant behavior.
authors: Department of Pathology & Microbiology, Faculty of Medicine, Saga University, Saga 849-8501, Japan. Electronic address: uchihash@cc.saga-u.ac.jp.
authors: Kazuyoshi
authors: K
authors: Uchihashi
authors: Aki
authors: A
authors: Nishijima-Matsunobu
authors: Atsuji
authors: A
authors: Matsuyama
authors: Fumio
authors: F
authors: Yamasaki
authors: Tsuyoshi
authors: T
authors: Tanabe
authors: Tetsuji
authors: T
authors: Uemura
authors: Naoko
authors: N
authors: Aragane
authors: Mai
authors: M
authors: Yakushiji
authors: Mihoko
authors: M
authors: Yamamoto
authors: Shigehisa
authors: S
authors: Aoki
authors: Shuji
authors: S
authors: Toda
mesh_terms: D000328:Adult; D002114:Calcinosis; D049109:Cell Proliferation; D003937:Diagnosis, Differential; D017809:Fatal Outcome; D005260:Female; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000378:metabolism; D005528:Foot / Q000473:pathology*; D015726:Giant Cells / Q000473:pathology; D006801:Humans; D007015:Hypophosphatemia, Familial; D007150:Immunohistochemistry; D008168:Lung / Q000473:pathology; D008175:Lung Neoplasms / Q000473:pathology / Q000556:secondary* / Q000601:surgery; D008637:Mesenchymoma / Q000378:metabolism / Q000473:pathology* / Q000556:secondary; D009364:Neoplasm Recurrence, Local / Q000378:metabolism / Q000473:pathology*; D009372:Neoplasms, Connective Tissue / Q000378:metabolism / Q000473:pathology* / Q000556:secondary; D012333:RNA, Messenger / Q000235:genetics; D012334:RNA, Neoplasm / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012983:Soft Tissue Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery
chemical_list: C000717427:FGF23 protein, human; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23
keywords: FGF23; Giant cells; Phosphaturic mesenchymal tumors of the mixed connective tissue type; Pulmonary metastasis