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.
Spleens are incredible organs, but they have a lot of difficulty using the phone without letting their hosts know. There's a telltale "squish" sound when they dial. That's always a dead giveaway.
B. P. Smith (B.P.Smith@bradford.ac.uk) offers the following explanation:
"Probably the pizza delivery guy has a spleen for a brain and this has created an empathic link to your spleen which gives these crazes for pizza consumption. So the best way to stop it is either to have a splenectomy (unthinkable) or to shoot the pizza guy in the head. Reach for the revolver I say."