The abdomen is the most frequent site of involvement in nonendemic Burkitt's lymphoma (small noncleaved cell). Some authors have proposed a role for extensive surgical resection or "second look" laparotomy in these patients. We retrospectively reviewed our series of 53 patients with Burkitt's lymphoma (1977 to 1990) to assess the role of surgery in their treatment. Patients were 2.5 to 21 years of age (median, 9.5 years) and 44 were males. The primary site of disease was the abdomen (38), head and neck (12), axilla (1), and bone marrow (2). Twenty-four of the 38 patients with abdominal primaries underwent laparotomy. Twelve of these patients presented with acute abdominal symptoms (right lower quadrant pain or intestinal obstruction) and at exploration underwent resection of the primary tumor. Ten of these 12 patients achieved grossly complete excision of tumor (9 had disease limited to the ileocecal area and adjacent mesentery and one had exophytic tumor adherent to the liver, which was excised). Of note, only 1 of these 12 patients had metastatic disease outside of the abdomen. The remaining 12 patients who underwent laparotomy had an incisional biopsy performed. Of the 14 patients who did not have a laparotomy, the diagnosis was made by bone marrow biopsy (6), and/or cytology of pleural fluid or ascites (6), lymph node biopsy (1), testicular biopsy (1), tibial biopsy (1), and percutaneous biopsy (1). Murphy staging for these 38 patients was: stage II (10), stage III (19), stage IV (5), and B cell acute lymphoblastic leukemia (ALL) (4). All patients received cyclophosphamide-containing combination chemotherapy regimens and stage III/IV/B cell ALL patients received central nervous system (CNS) prophylaxis.(ABSTRACT TRUNCATED AT 250 WORDS)