Primary appendiceal diffuse large B-cell lymphoma initially presenting as acute appendicitis: A case report.

INTRODUCTION: Diffuse large B-cell lymphoma (DLBCL) is the most common histologic subtype of non-Hodgkin lymphoma (NHL), accounting for approximately 25% of all NHL cases. Primary appendiceal lymphomas (PAL) presenting as acute appendicitis are very rare, occurring in only 0.015% of all cases of gastrointestinal lymphoma. CASE PRESENTATION: A 57-year-old man who was initially presented as acute appendicitis and subsequently underwent interval laparoscopic appendectomy. Pathological examination revealed diffuse large B cell lymphoma with cut end involvement. Whole-body positron emission tomography (PET) scan revealed enlarged right palatine tonsil and raised a suspicion of lymphoma involvement in two right cervical lymph nodes (level II and III); biopsy, however, showed that the lymph nodes were benign, with non-specific cellular changes. Bone marrow biopsy of the iliac crest also did not show lymphoma involvement. Subsequently, a diagnosis of primary appendiceal diffuse large B cell lymphoma (Ann Arbor Stage II) was established. After six courses of definite chemotherapy with cyclophosphamide, doxorubicin HCl, vincristine, and rituximab (R-CHOP), PET/CT showed complete remission of the prior FDG-avid malignancy of appendiceal DLBCL. The patient continued to be stable with no recurrence for fifteen months of regular outpatient department follow-ups. CONCLUSIONS: PAL is rare, and it clinically manifests the signs and symptoms of acute appendicitis. Specific characteristics of lymphoma in CT scans may lead to a more confirmative diagnosis. PET/CT is important for staging the lymphoma. Patients with PAL should be managed with surgical resection followed by R-CHOP-21 for 6 cycles regardless of whether they have localized disease or disseminated disease.