Hidden Malignancy: Ileocecal Intussusception as an Atypical First Presentation of Diffuse Large B-cell Lymphoma in Adulthood.

Intussusception is predominantly a pediatric condition, with only about 5 % of all intussusception cases occurring in adults with primary intestinal lymphomas comprising 1 %-4 % of gastrointestinal malignancies, 90 % of which are B-cell non-Hodgkin lymphomas (NHL). Diffuse large B-cell lymphoma (DLBCL), the most common subtype of NHL, often leads to intussusception without classical B symptoms. We present the case of a 33-year-old male with ileocolonic intussusception caused by a 4.8 × 5.3 × 5.5 cm enhancing mass. Histopathology and FISH confirmed DLBCL without MYC, BCL2, or BCL6 rearrangements, ruling out double- or triple-hit lymphoma. Following a right ileo-colectomy, R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) chemotherapy was initiated. This case underscores the role of malignancy in intussusception and highlights the importance of timely diagnosis and management.