Burkitt lymphoma/leukemia (BL) is a highly aggressive non-Hodgkin's lymphoma (NHL) often presenting in extranodal sites or as an acute leukemia. Because of the shared molecular and genetic features, the World Health Organization classification of lymphoid diseases recognizes the lymphomatous and leukemic phases of BL as a single entity: a mature B cell neoplasm, subtype Burkitt lymphoma/Burkitt cell leukemia. Because BL frequently appears in the stomach, we investigated the clinical presentation and outcome of gastric BL. We discovered 21 patients with gastric BL through a survey of our NHL registry, and retrospectively analyzed the distinct features of BL, including the St Jude/Murphy staging, other extranodal involvement, morphology and immunophenotype, response to treatment, and clinical outcome. The patients' median age was 48 years (range, 7-75), and the male-to-female ratio was 2.5. Stage 1 was found in five patients, stage 2 in five patients, and stage 4 in 11 patients. The stomach body and antrum were most frequently involved. All 21 patients were treated with systemic intensive chemotherapy, producing a 71% (15/21) rate of complete response (CR) to chemotherapy. Both the 2-year disease-free and overall survival rates were 55%. All ten patients in BL stages 1 and 2 showed outstanding outcomes, and nine of the ten patients exhibited CR and long-term survival. These data show that a high proportion of patients with gastric BL have a localized disease that is limited to stage 1 and 2, and that these localized BLs have outstanding outcomes. These findings suggest that these BLs could represent a distinct subtype that might have a different biology, which needs to be defined.