Diffuse Large B-Cell Lymphoma With Striking Intrasinusoidal Pseudoglandular Growth Pattern as a Diagnostic Dilemma Mimicking Metastatic Poorly Differentiated Pancreatic Adenocarcinoma in an Intraabdominal Lymph Node

We report an unusual intrasinusoidal growth pattern of an intraabdominal diffuse large B-cell lymphoma both clinically and histologically mimicking a metastatic adenocarcinoma. A 66-year-old woman presented with a high-grade distal biliary stricture with multiple enlarged abdominal lymph nodes. Frozen section at the time of pancreatoduodenectomy (“Whipple”) demonstrated cohesive nests of large atypical cells within a totally effaced lymph node presenting a diagnostic challenge. Immunohistochemistry proved this to be a diffuse large B-cell lymphoma extensively involving the sinusoids.