Richter Transformation: An Unexpected Diffuse Large B-Cell Lymphoma Within a Fatty Mesenteric Mass in a Patient With Refractory Chronic Lymphocytic Leukemia.

Richter transformation is the development of a high-grade lymphoma from chronic lymphocytic leukemia. This rare disease manifestation is difficult to predict and carries a poor prognosis. We describe the case of a 75-year-old man with refractory chronic lymphocytic leukemia who presented with multiple growing fatty abdominal masses on computed tomography and vague abdominal distension. The patient underwent exploratory laparotomy with mass resection due to the nonspecific imaging findings. A mesenteric mass was found to contain nodules of diffuse large B-cell lymphoma. This case highlights the importance of radiologists to consider the prospect tumor transformation in the differential diagnosis of enlarging abdominal masses.