title: Extra-articular diffuse-type tenosynovial giant cell tumor with benign histological features resulting in fatal pulmonary metastases.
abstract: Diffuse-type tenosynovial giant cell tumor (TS-GCT) is categorized as a locally aggressive but non-metastasizing neoplasm according to the WHO classification. Herein, we report an extremely rare case of a 41-year-old woman who developed multiple metastases from diffuse TS-GCT with benign histological features. The patient complained of a painful buttock mass and imaging studies revealed a soft tissue tumor of the buttock and multiple pulmonary nodules. The buttock tumor was excised and the final diagnosis was extra-articular diffuse-type TS-GCT. By video-assisted thoracic surgery, pulmonary nodules were pathologically identical to the primary tumor. Residual pulmonary nodules progressively grew, and she developed a muscle metastasis and a subcutis metastasis. She died of respiratory dysfunction due to multiple pulmonary metastases 1 year after primary surgery. Very few reports on histologically benign metastases from TS-GCT have been published, and the natural course of this rare condition remains unclarified. This rare case could provide important information for further clinical evaluation of this tumor.
authors.affiliation: 1 Department of Orthopaedic Surgery, National Hospital Organization Hokkaido Cancer Center, Sapporo, Japan.
authors.forename: Toshihisa
authors.initials: T
authors.lastname: Osanai
authors.affiliation: 2 Department of Diagnostic Pathology, National Hospital Organization Hokkaido Cancer Center, Sapporo, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: 1 Department of Orthopaedic Surgery, National Hospital Organization Hokkaido Cancer Center, Sapporo, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Hiraga
authors.affiliation: 1 Department of Orthopaedic Surgery, National Hospital Organization Hokkaido Cancer Center, Sapporo, Japan.
authors.forename: Tamotsu
authors.initials: T
authors.lastname: Soma
authors.affiliation: 3 Department of Pathology and Laboratory Medicine, Kanazawa Medical University, Uchinada, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nojima
mesh_terms: D000328:Adult; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary* / Q000628:therapy; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy; D013586:Synovitis, Pigmented Villonodular / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy
keywords: benign histology; diffuse type; fatality; pulmonary metastases; tenosynovial giant cell tumor