Burkitt's lymphoma presenting as acute appendicitis: a case report.

Appendiceal lymphomas are exceedingly rare, constituting around 0.015% of all gastrointestinal lymphoma cases. Burkitt's lymphoma is the second most prevalent pathology, diagnosed in 25.9% of patients. We report a case of a 36-year-old male admitted with acute abdominal pain with 2 days of evolution, localized in the right lower quadrant associated with hyporexia, but no fever. On examination he presented abdominal tenderness on the right iliac fossa. A diagnosis of acute appendicitis was made clinically. At the post-operative follow up, 2 weeks later, he presented a low back pain of high intensity, associated with swelling of the abdomen, night sweats, daily fevers and weight loss. The histopathological exam of the appendix revealed diffuse and transmural lymphoid proliferation. Immunohistochemistry suggested high grade B-cell lymphoma indicative of Burkitt's lymphoma. This patient was staged as a IVxB lymphoma and was submitted into polychemotherapy with a complete clinical response in 8 months.