Congenital abnormalities of the spleen

Absence of the spleen is rare, and when it occurs is often associated with congenital heart disease. Patients without a spleen are occasionally subject to fatal infection.

Splenunculi

These are single or multiple accessory spleens which are found near the hilum of the spleen in 50 per cent, related to the splenic vessels and behind the tail of the pancreas in 30 per cent, or in the splenic ligaments and mesocolon in the remainder. Up to 20 per cent of people have such splenunculi and most are no larger than 2 cm in diameter. Their importance lies in the fact that if not removed at the time of splenectomy they will undergo hyperplasia and may well be the site of persistent disease.

Hamartoma

Rarely, these are found in the spleen, usually being found incidentally at post-mortem examination. They vary in size from less than 1 cm in diameter to masses large enough to produce abdominal swelling. There are two varieties: one mainly lymphoid resembling the white pulp and the other resembling the red pulp. They are occasionally seen incidentally on CT scanning.

Splenic cysts

Nonparasitic cysts of the spleen are rare. They consist of true cysts formed from embryonal rests and include dermoids and mesenchymal inclusion cysts, or false cysts resulting from trauma which contain serous or haemorrhagic fluid. They can be clearly demarcated on scanning, punctured, drained and sclerosed. Operative removal is rarely, if ever, indicated.