Positive heterophile antibody test and massive splenomegaly in an adolescent with previously unsuspected Gaucher disease.

Mild splenomegaly is common in patients with Epstein-Barr virus-associated infectious mononucleosis. Massive splenomegaly, however, is rare and requires further evaluation to exclude other causes. We report an adolescent girl with previously undiagnosed type 1 Gaucher disease who presented with massive splenomegaly. The diagnosis of her underlying condition was hampered by the presence of a positive heterophile antibody test for infectious mononucleosis.