[A case of adenosquamous carcinoma with unknown origin and with superior vena cava syndrome as the first symptom].

This report is concerning a case of adenosquamous carcinoma having unknown origin and showing SVC syndrome as the first symptom. A 44 year-old man was admitted to our hospital because of facial edema at the beginning of April 1990. He was diagnosed as having a mediastinal tumor of the SVC syndrome type. Resection of the SVC tumor and part of the pericardium was performed on June 20, 1990. The operation had extraordinary findings. Lymph nodes adhering to tumor invaded the adjacent right side of the trachea and were situated in a rosette-like form. Furthermore, a part of the tumor stemmed into the lumen of the superior vena cava causing complete obstruction. The pathological diagnosis of the SVC tumor was adenosquamous carcinoma, however, no clinical examinations could identify its original matrix. Mediastinal tumors of unknown origin are reported as about 1% of all mediastinal tumors, and are responsible for 0.68% of all carcinomas in the mediastinum. This was one experience of a rare case of mediastinal tumor having unknown origin and showing SVC syndrome as the first symptom.