Supplementary Material for: Duodenal Obstruction Secondary to Diffuse Large B Cell Lymphoma in the Setting of Familial Mediterranean Fever: A Case Report

Introduction:
Diffuse large B-cell lymphoma (DLBCL) and Familial Mediterranean Fever (FMF) can both rarely present with small bowel obstruction (SBO), with their gastrointestinal symptoms sometimes overlapping. Clinicians should be aware not only of the signs and symptoms of potential malignancy, but also how such malignancy can present in patients with FMF. Distinguishing the presentation of both DLBCL and FMF will improve patient centered care and the workup and management of each individual condition. Furthermore, no known cases exist of a patient with concomitant FMF and DLBCL as possible drivers of SBO, highlighting the importance of keeping broad differentials in cases of diagnostic uncertainty and making this a rare presentation without clear consensus on best practices regarding management or diagnosis.

Case Presentation:
A 65-year-old man with a history of FMF presented with bilateral upper quadrant abdominal pain for 12 days, abdominal fullness/distention, decreased appetite, constipation with decreased stool caliber, bilious emesis, and unintentional weight loss over six months. An abdominal mass was discovered and DLBCL was diagnosed.

Conclusion:
While DLBCL proved to be the cause of obstruction in this patient, it is critical that clinicians maintain broad differentials in settings of diagnostic uncertainty. Since these diseases are not regularly encountered by many clinicians, their presentation and management are valuable to review, especially in the setting of an entity as common to inpatient medicine as bowel obstruction. The review of DLBCL and FMF, as well as the maintaining of broad differential diagnoses, will greatly improve the care clinicians provide to their patients.