Metastatic intestinal adenocarcinoma to a lymph node involved by follicular lymphoma: The importance of looking beyond the apparent.

Composite tumors consisting of follicular lymphoma (FL) and colorectal or small intestinal adenocarcinoma are exceedingly rare, with only four cases published in the literature, to the best of our knowledge. While in most of these cases the clinical prognosis seems to be determined by the adenocarcinoma, at least one patient has shown rapid and aggressive progression of the FL. Here we report on a 62 year-old male with colonic adenocarcinoma metastatic to a retroperitoneal lymph node involved by FL, which illustrates the importance of carefully examining the histomorphology of lymphoid elements in surgical specimens.