tAccessory spleens are common, usually asymptomatic,
incidentally discovered on imaging of the abdominal imaging. They are
congenital foci of splenic tissue. They occupy variable locations separate from
the main spleen. They also vary in location, and tend to occur most commonly
near the splenic hilum (a location on the surface of the spleen. It is the
point of attachment for the gastrosplenic ligament, and the point of insertion
for the splenic artery and splenic vein.), with almost 20% in or near the tail
of the pancreas. These are considered to be congenital normal variants.
Accessory spleens can range in size from a few millimeters to several
centimeters. They have been reported to be present in 16% of patients
undergoing abdominal imaging, and as many as 30% of patients during autopsy.