[Infectious mononucleosis and splenic pseudocyst: presentation of a case].

The authors report the clinical case of an 18-year-old patient who presented with a symptomatic mass in the left upper quadrant 6 months after having infectious mononucleosis. The preoperative investigation consisted principally of echography and computerized axial tomography of the abdomen, which demonstrated a cystic mass of the lower pole of the spleen. Splenectomy was carried out. Histologic examination showed a pseudocyst of the spleen with a fibrous capsule without an epithelial lining. The treatment and pathogenesis of pseudocysts of the spleen secondary to infectious mononucleosis are discussed.