Mediastinoscopy as an emergency diagnostic procedure in superior vena cava syndrome.

Seven men and one woman (aged 20-70 years) with superior vena cava syndrome underwent diagnostic mediastinoscopy to elucidate the cause, which other, lesser procedures had not identified. Intraoperative frozen-section studies of the biopsy specimens revealed small-cell carcinoma (4 cases), large-cell carcinoma (1), squamous-cell carcinoma (1), large-cell lymphoma (1) and Hodgkin's lymphoma (1). Radiotherapy or chemotherapy was initiated within the following 24 hours in six cases. One of the tumors intraoperatively diagnosed as small-cell carcinoma was subsequently reclassified as lymphocytic lymphoma. Complicating hemorrhage from the right carotid artery required median sternotomy in one case and wound infection occurred in another. There was no mediastinoscopy-related mortality. Mediastinoscopy is useful and reliable in the diagnostic emergency posed by the superior vena cava syndrome.