Infectious mononucleosis manifested as a cecal mass.

An 11-year-old boy presented with symptoms of periappendiceal abscess. At laparotomy, a tumor-like mass involving the ileocecal mesentery and adjacent part of the cecum and covered by the omentum was found. A right hemicolectomy was performed, followed by primary ileocolic anastomosis. On histologic examination, the tumor-like mass proved to be a lymph node block pushing the adjacent wall of the cecum. The overall histologic and immunophenotypic findings were consistent with (a) abnormal immune lesion mimicking lymphomatous process because of infection by Epstein-Barr virus and (b) extensive acute inflammatory infiltration of the cecum and adjacent tissues.