Splenectomy for the massively enlarged spleen. The experience at the National Cancer Institute from 1955 to 1988 with 46 cases of splenectomy for massive splenomegaly (greater than or equal to 1,500 grams) was reviewed to assess the indications, pathology, operative, and postoperative course for this procedure. The median age was 51 years. Thirty-one splenectomies (67.4%) were performed for malignancy (chronic lymphocytic leukemia, 11; chronic myelogenous leukemia, 10; lymphoma, 9; hairy cell leukemia, 1), 11 for myeloid metaplasia, and four for other nonmalignant conditions. Indications for splenectomy included hypersplenism (32 patients), symptoms (6), diagnosis (3), and splenic rupture (3). A midline incision (30 patients) was most commonly used. Median operative time was 2 hours, 50 minutes. Median operative blood loss was 1,300 ml (range, 100 ml-60 units). The splenic artery was ligated initially in 16 patients (34.8%) but did not correlate with blood loss or operating time. The median splenic weight was 2,030 grams (range, 1500-5320 gm). The postoperative complication rate was 39.1 per cent (21 complications in 18 patients). This included infection in 10 patients, bleeding in six patients. Six patients required reoperation (bleeding, 4; abscess, 1; small bowel obstruction, 1 patient). The 30-day operative mortality was 19.6 per cent (9 patients). Excluding operative deaths, 35 patients were available for follow-up evaluation. Twenty-nine patients had improvement in parameters for which splenectomy was indicated. Six patients had no change in their course after splenectomy. These findings indicate that many patients with massive splenomegaly benefit from splenectomy, however, the procedure is associated with a high risk for postoperative morbidity and mortality. 