A 51-year-old gentleman with a history of human immunodeficiency virus and liver mass was status post-biopsy showing diffuse large B-cell lymphoma (DLBCL) as shown in figure 1and 2. He presented with acute pain abdomen. On physical examination, the patient was hemodynamically unstable, with a blood pressure of 90/60 mmHg with a heart rate of 112 beats/min was measured. The abdomen was tense, guarded, and rigid.

A clinical workup revealed:

·       Leukocytosis with a white blood cell count of 15,000/mm3 (reference range: 3400–9,100).

·       Liver function test, lipase, and lactate were all within normal limits.

A computed tomography scan of the abdomen showed visceral perforation (figure 3). The patient underwent emergency explorative laparotomy that revealed ileal perforation. Small bowel resection pathology was positive for DLBCL (figure 4) and showed mucosal and muscular propria ulceration and acute serositis. Immunohistochemical (IHC) results demonstrated cluster of differentiation (CD)20+ (figure 5). Immunoglobulin gene rearrangement was noted in IGH with B-Cell lymphoma 6 (BCL6) rearrangement, and there was a gain of BCL6 and MYC without double/triple hit mutation. The proliferative index was high with Ki67 (100%). Without double/triple hit mutation and Ki67 (100%). A staging workup with positron emission tomography (PET), magnetic resonance imaging of the brain, lumbar-puncture, and bone-marrow biopsy was negative except for the presence of fluorodeoxyglucose-avid lymph nodes in the neck and inguinal and gastro-pancreatic areas. He received six chemotherapy courses with etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab (DA R-EPOCH) and four prophylactic courses of intrathecal methotrexate along with antiretroviral therapy. The follow-up PET scan showed a high-grade positive therapeutic response with no lymphoma involvement.

PRIMARY EXTRANODAL ILEAL DIFFUSE LARGE B-CELL LYMPHOMA

Diffuse large B-cell lymphoma is an aggressive form of non-Hodgkin’s lymphoma (NHL) with primary lymph node involvement. Extranodal DLBCL is less common, with the small intestine is the most common site for primary extranodal DLBCL, which constitutes about 50-60% of all gastrointestinal tumors (GI) [1]. Primary GI lymphoma presenting as spontaneous bowel perforation is rare. Primary extranodal GI lymphoma should be one of the differentials for patients presenting with acute abdomen and visceral perforation.

MANAGEMENT OF DLBCL

DLBCL management is based on IHC, gene mutation and rearrangements, and the mitotic proliferative tumor index [2]. DLBCL with double or triple hit mutation, which involves rearrangement/translocation of BCL2, BCL6, and MYC, presents clinically aggressive tumors [2]. The first-line treatment for high-grade B-cell lymphoma is DA R-EPOCH [3]. In GI lymphoma, surgical resection followed by adjuvant chemotherapy remains the mainstay of treatment [4]. In our patient, there was a rearrangement of BCL6 with a high proliferative index. He underwent explorative laparotomy followed by adjuvant chemotherapy. He also received antiretroviral treatment along with chemotherapy.

References.

1. Howell JM, Auer-Grzesiak I, Zhang J, et al. Increasing incidence rates, distribution and histological characteristics of primary gastrointestinal non-Hodgkin lymphoma in a North American population. Canadian journal of gastroenterology = Journal canadien de gastroenterologie. 2012 Jul;26(7):452-6.

2.  Pasqualucci L, Dalla-Favera R. Genetics of diffuse large B-cell lymphoma. Blood. 2018 May 24;131(21):2307-2319.

3. Zhang XY, Liang JH, Wang L, et al. DA-EPOCH-R improves the outcome of the R-CHOP regimen for DLBCL patients below 60 years, GCB phenotype, and those with high-risk IPI, but not for double expressor lymphoma. Journal of cancer research and clinical oncology. 2019 Jan;145(1):117-127.

4. Lightner AL, Shannon E, Gibbons MM, et al. Primary Gastrointestinal Non-Hodgkin’s Lymphoma of the Small and Large Intestines: a Systematic Review. Journal of Gastrointestinal Surgery. 2016 2016/04/01;20(4):827-839.