Unexpected diagnosis of acute lymphoblastic leukemia in a 2-year-old with acute appendicitis – Case report

INTRODUCTION AND IMPORTANCE: Appendicitis is an extremely common surgical problem, especially in the pediatric population. However, leukemic infiltration of the appendix is rare and even more so is having acute appendicitis as the initial manifestation. CASE PRESENTATION: The patient is a 2-year-old female with multiple febrile illnesses since birth, who presented to the emergency department with a 3-day history of abdominal pain, fever, and decreased appetite. Ultrasound of her right lower quadrant was consistent with acute appendicitis. A laparoscopic appendectomy was performed successfully without complication. However, pathological examination of the specimen revealed an appendix with partial involvement of B-lymphoblastic lymphoma/leukemia in a background of lymphoid hyperplasia. This prompted referral to a pediatric hematologist/oncologist. Further workup revealed abnormal immature cells on peripheral blood flow cytometry. Bone marrow biopsy confirmed a diagnosis of B-cell acute lymphoblastic leukemia. CLINICAL DISCUSSION: Though acute appendicitis is very common and management is well documented, it is rare for pathological examination to uncover leukemia as an underlying etiology and to have acute appendicitis as the initial manifestation of hematologic malignancy. To our knowledge, very few similar events have occurred and been documented in the medical literature. CONCLUSION: Physicians and surgeons should be aware that, though quite rare, leukemic infiltration of the appendix can occur and should be considered in the differential diagnosis of acute appendicitis. Notably, pathologic examination of the appendix may be particularly informative. Diligent follow-up of abnormal pathology is crucial in cases suggestive of underlying hematologic malignancy.