Profound EBV-driven lymphoid hyperplasia of rectal tonsil mimicking high grade lymphoma

We present an unusual case of a localized EBV-driven lymphoproliferation within the rectum showing histological features suggestive of malignant lymphoma. The rectal lymphoid tissue (rectal tonsil) contained an infiltrate composed of large, transformed lymphoid cells with prominent nucleoli and immunoblastic morphology. These cells showed an abnormal phenotype, CD30 expression and EBER positivity. The patient was otherwise well, with no evidence of disease at others sites, and PCR studies found no evidence of clonality. EBV related lymphoid proliferation with transformed cells is well recognized in the palatine tonsil in association with infectious mononucleosis, but similar appearances are not described in the rectum.