Burkitt Lymphoma of the Appendix Presenting With Acute Appendicitis and Acute Kidney Injury: A Case Report and Review of Literature.

The gastrointestinal tract is one of the most common sites for extranodal Burkitt lymphomas (BLs), but an appendiceal BL is extremely rare. We describe a case of appendiceal BL presenting with acute appendicitis and acute kidney injury. A 15-year-old obese male presented to the emergency department with fever and right-sided abdominal pain. WBC count was slightly increased, and a CT scan of the abdomen showed features of ruptured appendicitis and peritonitis. The patient was placed on antibiotics, and an interval appendectomy was planned. The patient developed a worsening acute kidney injury one day later, requiring a laparoscopic appendectomy. Gross examination of the appendix revealed a dilated, firm, sausage-like appendix with a hemorrhagic serosa and a firm mesoappendix. Microscopic examination of the appendix showed a dense diffuse infiltration of monomorphic medium-sized atypical lymphoid cells with round nuclei, dispersed chromatin, and small nucleoli. Few scattered macrophages created a vague "starry sky" appearance. Many mitotic figures were seen. The lesion also involved the mesoappendix. Immunohistochemical analysis showed that the lymphoma expressed CD10, CD20, and BCL6 but was negative for CD34, BCL2, and TdT. Later, the fluorescence in situ hybridization (FISH) analysis detected an IGH-MYC (8;14) fusion. A final diagnosis of appendicular Burkitt lymphoma was made. Two weeks later, a bone marrow biopsy performed for staging showed involvement of bone marrow by BL. The patient lost follow-up after that due to the transfer of care to another hospital.