This article is from the the official alt.spleen FAQ, by Andrew Stellman with numerous contributions by others.
Andrew says: NOTE: PLEASE DO NOT SEND ANY MAIL TO ME REQUESTING MEDICAL ADVICE! I AM NOT A DOCTOR, AND WILL NOT GIVE YOU ANY USEFUL INFORMATION.
Yes. Slight enlargement of the spleen is normal during and after digestion, and the size of the spleen in human adults usually ranges from 100 to 250 grams (3.5 to 8.3 ounces). Abnormal enlargement, or splenomegaly, may occur in the course of a number of diseases. For some of these diseases, and in the case when the spleen ruptures, surgical removal of the organ (splenectomy, as horrible as the thought may be) may prove to be beneficial. Splenectomy is not recommended except in the very worst cases, since severe depression generally ensues, and suicide often follows.