title: Primary synovial sarcomas of the mediastinum: a clinicopathologic, immunohistochemical, and ultrastructural study of 15 cases.
abstract: A series of 15 cases of primary mediastinal neoplasms displaying histopathologic, immunohistochemical, and ultrastructural features of synovial sarcoma is presented. The patients' ages ranged from 3 to 83 years, with a male-to-female ratio of 2:1. Nine cases presented as anterior mediastinal masses with chest pain, shortness of breath, and pleural effusion, and 6 cases were in paravertebral location in the posterior mediastinum and presented with neck or back pain and pleural effusion. The tumors measured from 5 to 20 cm in greatest diameter and showed a tan white, soft to rubbery cut surface with areas of hemorrhage and necrosis and foci of gelatinous material. Four cases showed areas of cystic degeneration. In 7 cases, the tumors were well circumscribed; in 6 cases, the tumors grossly invaded the pleura, pericardium, heart, great vessels, chest wall, rib, and vertebra. Histologically, 5 cases displayed a biphasic growth pattern, with well-formed glandular elements admixed with a monotonous spindle cell population. Ten cases were exclusively composed of a monotonous atypical spindle cell proliferation. Immunohistochemical studies showed focal positivity of the tumor cells for cytokeratin and/or epithelial membrane antigen, and strong positivity for vimentin and bcl-2 in the spindle cells in all cases studied (10 of 10). Eight cases also showed focal positivity for CD99. Electron microscopic examination in 5 cases showed oval to spindle tumor cells with closely apposed cell membranes, abundant cytoplasmic intermediate filaments and rough endoplasmic reticulum, and immature desmosome-type cell junctions. Ten patients were treated by complete surgical excision and two by partial excision followed by radiation therapy. In 4 patients, the tumors were inoperable and treated with radiation therapy only. Clinical follow-up was available in 5 patients and showed local recurrence with metastases to lung, lymph nodes, and epidural space from 1 to 3 years in 4 cases and liver metastases and death due to tumor after 6 month in 1 case. Synovial sarcoma should be considered in the differential diagnosis of biphasic and monophasic spindle cell neoplasms of the mediastinum.
authors.affiliation: Department of Pathology, Division of Anatomic Pathology, Ohio State University, Columbus, OH 43210, USA. suster.3@osu.edu
authors.forename: Saul
authors.initials: S
authors.lastname: Suster
authors.forename: Cesar A
authors.initials: CA
authors.lastname: Moran
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D002467:Cell Nucleus / Q000648:ultrastructure; D002675:Child, Preschool; D003131:Combined Modality Therapy; D003896:Desmosomes / Q000648:ultrastructure; D005260:Female; D006801:Humans; D007633:Keratins / Q000032:analysis; D008297:Male; D008479:Mediastinal Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000628:therapy; D046529:Microscopy, Electron, Transmission; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local; D013902:Radiography, Thoracic; D013584:Sarcoma, Synovial / Q000737:chemistry / Q000473:pathology* / Q000628:therapy; D014057:Tomography, X-Ray Computed
chemical_list: D014408:Biomarkers, Tumor; D007633:Keratins