Asplenia is the absence of spleen and/or its functions. Abnormalities of the spleen may be classified on a pattern oriented approach, based on splenic imaging. These include anomalies of the following:
Shape (clefts, notches, lobules)
Location (wandering spleen)
Number (asplenia, polysplenia)
Size (splenomegaly, atrophy)
Solitary lesions (cysts, lymphangiomas, hemangiomas, hamartomas)
Multiple lesions (trauma, infections, neoplasms, storage disorders)
Diffuse disease (infarction, heavy metal deposition, peliosis)
Absence of splenic tissue can be total (congenital asplenia) or partial (hypoplastic) from birth.
Loss of splenic tissue due to surgical removal may occur later in life as a result of trauma that causes rupture of the organ. The spleen may be removed in other conditions (eg, hemoglobinopathies) to improve the red cell life expectancy. Removal of the spleen may be undertaken as a result of being involved in a neoplastic processor as a staging procedure in some cancers. Occasionally, the spleen may be removed to address the sheer mass effect of a massive enlargement (such as in storage disorders), which can cause mass effects.
Autosplenectomy is the process where the spleen loses its function due to multiple and repeated infarctive episodes, as in sickle hemoglobinopathies. See the image below.