Pediatric patients presenting with anterior mediastinal masses between January 1980 and November 1988 were reviewed to assess the correlation between tracheal cross-sectional area and anesthetic risks. Forty-two patients had evaluable computed tomography (CT) scans and underwent a surgical procedure. Thirty-four patients had Hodgkin's disease, six had non-Hodgkin's lymphoma, and two had mediastinal teratoma. Tracheal cross-sectional areas were greater than 75% of expected in 19 cases, greater than 50% to 75% in 16 cases, greater than 25% to 50% in five cases, and less than or equal to 25% in two cases. The presence or extent of symptoms did not correlate well with the degree of tracheal narrowing shown by CT scan except for orthopnea. Local anesthesia was used primarily in patients with significant tracheal narrowing (tracheal size was less than or equal to 56% in 5 of 6 patients). General anesthesia with spontaneous ventilation by mask was performed in four patients with tracheal areas of 33%, 73%, 76%, and 98% of expected. General endotracheal anesthesia was utilized in the remaining 32 patients, only three of whom had tracheal areas of less than 50% of expected (down to 30%, 26%, and 24% of expected) and one received preoperative radiotherapy (26%). None of these 32 patients had symptoms of orthopnea or dyspnea at rest, and only one had dyspnea on exertion. All tolerated anesthesia without difficulty. No patient in this series suffered respiratory or cardiovascular collapse during surgery. Adequate biopsy material was obtained in all cases.(ABSTRACT TRUNCATED AT 250 WORDS)