Splenic cysts, although not particularly common, are the most common focal lesion of the spleen. They may be congenital or secondary.
The incidence is ~0.75 per 100,000.
Usually asymptomatic and incidentally discovered at imaging. Left upper quadrant pain and tenderness, and splenomegaly can rarely occur.
Splenic cysts can be primary (10-25%) or secondary (~80%).
Primary splenic cysts
congenital epidermoid splenic cysts, or primary splenic cysts, are lined by epithelium (true cyst) and are usually solitary
- a genetic defect of mesothelial migration is considered the cause
- most common in children and young adults
- at gross pathology, they are usually large with glistening smooth walls
- wall calcification uncommon (~15%), but wall trabeculations/septations are common (~85%)
Secondary splenic cysts
- secondary splenic cysts may be due to
- post traumatic: the end stage of splenic haematoma or splenic infarction with resultant liquefactive necrosis and cystic change. At gross pathology they are usually smaller than true cysts and contain debris and wall calcification (50%). Septations are uncommon.
- pyogenic splenic abscesses
- a complication of pancreatitis such as pseudocyst or walled off necrosis adjacent to spleen
- pancreatic pseudocysts extend beneath pancreatic tail to gain entry to the spleen via the splenic hilum and capsule
- hydatid cyst (2% of patients with hydatid disease)
Usually shows an anechoic to hypoechoic well defined intrasplenic lesion. Internal echoes may be present depending on aetiology. Their margin may be echogenic and they are surrounded by normal splenic tissue 3.
Typically shows a hypoattenuating relatively well-defined intrasplenic lesion. The wall is thin and has a sharp demarcation to splenic parenchyma. There is no rim or internal enhancement. Wall calcification may be present.
A number of splenic lesions may appear cystic, depending on the modality (for a complete list see cystic lesions of the spleen article):
- congenital (tend to be unilocular in a majority of cases)
- post traumatic 'false' cyst
- cystic splenic metastases
- intrasplenic pancreatic pseudocyst
Treatment and prognosis
Small and asymptomatic cysts do not require treatment. Symptomatic cysts are managed surgically.
Complications are rare and include haemorrhage, rupture and infection 6-7.
- normal appearance of the spleen
- pseudolesion of the spleen: inhomogeneous splenic enhancement
splenic lesions and anomalies
- congenital anomalies
- mass lesions
- infiltrative processes
- incidental splenic lesion (approach)
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