Diffuse Large B-cell Lymphoma Mimicking Pancreatic Carcinoma and the Use of Immunohistochemistry in Resolving the Diagnostic Dilemma After Postmortem Examination: A Case Report.

Diffuse large B-cell lymphoma is the most common lymphoma, accounting for 30% of all non-Hodgkin lymphomas; they can grow rapidly and often present as masses infiltrating tissues or obstructing organs. We report the case of a 58-year-old female who presented with a one-month history of generalized body weakness and weight loss with a two-week history of yellowness of the eyes, fever, dyspnea, and bilateral leg swelling. Examination at presentation revealed pallor, fever, jaundice, hepatomegaly, and bilateral pitting pedal edema. Laboratory investigations revealed severe anemia, deranged clotting profile, azotemia, elevated liver enzymes, and elevated tumor markers CA125, CEA, and CA 19.9. Abdominal ultrasound showed hepatomegaly and a large head of the pancreas. The initial diagnosis was obstructive jaundice due to carcinoma of the head of the pancreas. Despite all care offered, her clinical condition deteriorated until she died on the 12th day of admission. A postmortem examination showed a mass in the head of the pancreas and bile duct, enlarged para-aortic and mesenteric lymph nodes with ascites, pericardial nodules, and bronchopneumonia. Histological and immunohistochemical analysis of postmortem biopsies confirmed the diagnosis of a diffuse large B cell lymphoma.  This case highlights the diagnostic dilemma often seen in disseminated diffuse large B-cell lymphoma. The patient presented with features referable to different organs and systems. If detected early, most cases respond to standard immuno-chemotherapy. However, it can also become rapidly fatal and ultimately lead to death, as seen in this case.