An accessory spleen, also called a splenunculus, is a small nodule of normal splenic tissue located separate from the main spleen. It is a common anatomical variant found in roughly 10 to 15 percent of the population, usually near the splenic hilum or in the tail of the pancreas. On ultrasound, an accessory spleen typically appears as a small, round, homogeneous mass that has the same echotexture as the main spleen. Recognizing this normal variant is important so that it is not mistaken for a lymph node, tumor, or other pathological finding.
Sonography Term