title: Primary synovial sarcoma of the thyroid gland.
abstract: Synovial sarcoma is a rare but distinct soft tissue neoplasm, most commonly occurring in para-articular regions of the extremities of young adults and also occurring in the head and neck region. To the best of our knowledge, only one case of primary synovial sarcoma of the thyroid has been previously reported. Here, we report a 15-yr-old man who had a chief complaint of a palpable neck mass. The neck computed tomography revealed a relatively well-demarcated solid mass in the left thyroid gland. After fine needle aspiration cytology, total thyroidectomy and lymph node dissection were performed. Grossly, the mass was covered by the same capsule as the thyroid gland, measuring 6X5X5 cm in dimensions and weighing 78 gm. The cut surface showed a well demarcated, lobulated, grayish tan, and rubbery solid tumor. Histologically, this tumor was a biphasic synovial sarcoma. Immunohistochemical, ultrastructural, genetic studies, and cytologic findings were all consistent with synovial sarcoma. When synovial sarcomas arise in this unusual site, recognition and differential diagnosis become more difficult. The differential diagnosis of a spindle epithelial tumor with thymus-like differentiation is very difficult due to their similar clinical, histological, and immunohistochemical features. Ultrastructural and cytogenetic studies for synovial sarcoma are necessary to establish a definitive diagnosis.
authors.affiliation: Department of Pathology, College of Medicine, Hanyang University, Seoul, Korea.
authors.forename: Ki Seok
authors.initials: KS
authors.lastname: Jang
authors.forename: Kyueng Whan
authors.initials: KW
authors.lastname: Min
authors.forename: Si Hyong
authors.initials: SH
authors.lastname: Jang
authors.forename: Seung Sam
authors.initials: SS
authors.lastname: Paik
authors.forename: Kyung
authors.initials: K
authors.lastname: Tae
authors.forename: Se Jin
authors.initials: SJ
authors.lastname: Jang
authors.forename: Moon Hyang
authors.initials: MH
authors.lastname: Park
mesh_terms: D000293:Adolescent; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D008297:Male; D046529:Microscopy, Electron, Transmission; D013584:Sarcoma, Synovial / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology*; D013964:Thyroid Neoplasms / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology*; D014746:Vimentin / Q000378:metabolism
chemical_list: D014746:Vimentin; D007633:Keratins