Florid reactive lymphoid hyperplasia of the terminal ileum in adults: a condition bearing a close resemblance to low-grade malignant lymphoma

Five cases of florid lymphoid hyperplasia of the ileocaecal region are described. This condition is characterized by large reactive germinal centres and a diffuse infiltrate of lymphoid cells and eosinophils which extends through the muscularis propria. There is a close resemblance to low‐grade malignant lymphoma from which it can be distinguished only by the use of immunocytochemistry for light‐chains. Using this technique it should be possible to classify all such lymphoid proliferations as either reactive or neoplastic and to eliminate ambiguous labels like pseudolymphoma.