DISEASES OF SPLEEN

DISEASES OF SPLEENCONGENITAL ABNORMALITIES

There are complex congenital heart syndromes that are associated with situs anomalies and involve the spleen.

Bilateral right sidedness is associated with a transverse liver, asplenia, two right atria, and two right lungs.

Bilateral left sidedness has absent gall bladder, polysplenia, two left lungs, and different forms of congenital heart disease.

Small accessory areas of splenic tissue are called splenunculi; they are encountered commonly on ultrasound and CT, sometimes being misdiagnosed as solid masses. If present, they may enlarge progressively if the patient undergoes splenectomy.

42-year-old woman with polysplenia syndrome. Axial CT scan shows two spleens (Sp) to right of midline. Gallbladder (GB) is near midline and stomach (S) is on right. Pancreas is indicated by (P).

Splenic traumaSplenic injury can be either accidental or iatrogenic

Most commonly associated with blunt trauma

Often occurs in the presence of lower rib fractures

May be common clinically apparent either early or delayed.

Delayed injury is usually due to rupture of subcapsular haematoma

20% of splenic injuries occur inadvertently during other abdominal operations

In some patients spontaneous rupture can occur following trivial trauma

GradingGrade I – Minor subcapsular tear or haematomaGrade II – Parenchymal injury not extending to the hilumGrade III – Major parenchymal injury involving vessels and hilumGrade IV – Shattered spleen

42-year-old man with grade IV traumatic splenic injury. Axial CT images show multiple splenic lacerations extending to hilum with active contrast extravasation and hemoperitoneum.

Infection and Inflammatory ConditionsCalcified lesions within the spleen can result from previous tuberculosis or histoplasmosis infection. Haematomas may also calcify. Diseases such as malaria and kala-azar that are common world wide cause significant splenomegaly, but have no specific imaging features.

Nodular splenic calcification in tuberculosis. Other causes include Histoplasmosis, coccidiodomycosis, brucellosis, hemangiomas and sickle cell anemia

Curvilinear calcification is seen in the spleen. The common differential diagnosis are Simple cyst, Hydatid cyst or large aneurysm.

CT demonstrates a very large cystic mass in the spleen with peripheral calcification. Features are consistent with a hydatid cyst.

Axial contrast-enhanced CT images (2nd image is a maximum-intensity projection image) show a 2-cm saccular aneurysm (arrows) of the mid splenic artery in a 38-year-old woman with idiopathic hepatic cirrhosis, portal hypertension and splenomegaly.

CA = celiac artery

 Contrast enhanced image, in arterial phase, demonstrates several hilar splenic aneurysms. The largest and pointed one in this figure has an egg-shaped mural calcification and a partial luminal thrombosis.

This contrast enhanced axial image, in portal phase, also shows the hilar splenic aneurysms, still well opacified. This may indicate a slow arterial flow.

Neoplastic Disease

Secondary metastatic disease may affect the spleen, but it is usually asymptomatic;

primary malignancies are exceedingly rare.

The most significant splenic involvement in malignant disease occurs in lymphomas, but both the ultrasound and CT appearances often shows only splenomegaly, they have a low sensitivity with a high false negative rate for the disease.

Vascular Disorders

The spleen is as liable to infarcts as other organs and tissue.

Wedge-shaped defects may be seen on ultrasound and CT.

They are usually an incidental fining, but are more common in patients with hyper-splenism.

Splenomegaly occurs in portal hypertension and other causes of increased back pressures on the portal venous system, such as portal vein thrombosis.

Calcification of the splenic artery is common in the elderly, and atheromatous aneurysms may also occur.

CT scans with IV contrast in 77-year-old woman. Serous cystadenoma of tail of pancreas shows heavy splenic artery calcifications (arrow).

SPLEENIC VEIN VARICESVarices medial to the spleen mimicking an accessory spleen. (a) Pre-contrast CT, showing an oval mass ( ), ★measuring 2 cm × 1.5 cm, medial to the spleen. Its attenuation on this unenhanced scan is similar to that of the spleen. (b) On post-contrast CT, the mass has enhanced to a greater degree than the splenic parenchyma and is therefore not an accessory spleen. (c) 2 cm caudal to (b). Multiple round masses of higher attenuation than the spleen and situated medial to the spleen represent typical varices (v). Note the large spleen, secondary to liver cirrhosis.

Wandering spleen in a 7-year-old girl.(a) Contrast-enhanced CT scan reveals an anterior mass at the level of the cecal pole (solid arrows) with vessels entering posteromedially (open arrow). (b) Tc-99m sulfur colloid scintigram shows the mass to be an abnormally located spleen (arrow). The liver also demonstrates radiotracer uptake (top).

A wandering spleen is one that is found in a location other than the left upper quadrant. This wandering ability may be due to congenital absence of the ligaments that tether the spleen in place, with the lienorenal ligament being the most important. Hormonally induced laxity of ligaments (e.g., during pregnancy) can also allow the spleen to wander off. 

Splenomegaly in a 15-year-old boy with cystic fibrosis, cirrhosis, and portal hypertension. Contrast-enhanced CT scan obtained at the level of the superior mesenteric artery shows a portosystemic shunt (arrow).

 Cavernous transformation of the portal vein in a 16-year-old girl with idiopathic portal hypertension who presented with hypersplenism. Coronal T1-weighted  MR image show massive splenomegaly. Multiple low-signal-intensity lesions are seen within the spleen. These lesions are due to susceptibility artifact from hemosiderin-laden siderotic nodules, which developed secondary to repeated hemorrhage.

Splenomegaly secondary to acute sequestration crisis in a 20-month-old girl with sickle cell anemia. An enlarged spleen was palpated at physical examination. Abdominal radiograph shows a large, soft-tissue structure in the left upper quadrant.

Focal artifact in a 10-year-old boy with a history of lymphoproliferative disorder who had undergone liver transplantation. Contrast-enhanced CT scan shows focal low-attenuation artifact mimicking a splenic mass (arrow).

 Epidermoid cyst in a 7-year-old boy. Contrast-enhanced CT scan demonstrates a splenic epidermoid cyst (arrow). The lesion was initially discovered at US for urinary tract infection. The diagnosis was confirmed at histopathologic analysis.

 Spontaneous splenic rupture in a 15-year-old boy with splenomegaly who had undergone bone marrow transplantation for leukemia. US showed nonspecific heterogeneity of the splenic echotexture. On a contrast-enhanced CT scan, the splenic fragments are readily appreciated (arrows).

Calcified granulomas due to congenital cytomegalovirus infection in a 2-day-old girl.(a) Abdominal radiograph shows calcifications within the liver (open arrow) and spleen (solid arrow). (b)Unenhanced CT scan (bone window) shows the extent of the calcifications more clearly (arrowhead).

Pyogenic splenic abscess in a 2-year-old girl with aplastic anemia. Contrast-enhanced CT scan shows a well-defined, low-attenuation lesion in the tip of the spleen (arrow). The abscess was drained, and culture was positive for E coli and mixed gram-positive organisms.

Leukemic involvement of the spleen in a 13-year-old girl with sickle cell disease. Transverse US scan through the splenic hilum shows multiple hypoechoic nodules (arrows). The spleen was not enlarged, and there was no evidence of recurrent disease elsewhere within the abdomen.

Multifocal splenic lymphoma in a 17-year-old girl with Hodgkin disease. Contrast-enhanced CT scan obtained just inferior to the level of the splenic hilum shows multiple low-attenuation nodules of varying size within an enlarged spleen. Moderate hepatomegaly and intraabdominal lymphadenopathy (not shown) were also found.

Multifocal masses from lymphoproliferative disease in a male infant who had undergone liver transplantation. Contrast-enhanced CT scan shows multifocal low-attenuation masses in the spleen and liver.

Gaucher disease in an adolescent girl. Axial T1-weighted (a) and T2-weighted fast spin-echo(b) MR images obtained at routine follow-up show massive splenomegaly with areas of low signal intensity (arrows). These findings are consistent with fibrosis after splenic infarction, which is typical with Gaucher disease.

Splenic infarction secondary to severe fungal infection in an immunocompromised 4-year-old boy. Contrast-enhanced CT scan shows several large, wedge-shaped areas of nonenhancing splenic tissue. The liver is enlarged.

Splenic infarction secondary to idiopathic pancreatitis and splenic vein thrombosis in an adolescent girl. Contrast-enhanced CT scan obtained at the level of the pancreatic tail shows a nonenhancing spleen. The pancreatic tail is inflamed, and there is subjacent stranding in the peripancreatic and splenic fat (arrow).

Splenic infarction in a 7-year-old boy with sickle cell disease. Contrast-enhanced CT scan shows a predominantly low-attenuation enlarged spleen with capsular enhancement (arrow). This finding is due to a separate arterial supply to the splenic capsule.

 Splenic hemosiderosis due to iron overload secondary to transfusions for sickle cell anemia. Axial T1-weighted MR image shows low signal intensity secondary to reduced T1 and T2 in both the liver and spleen. This finding is due to a combination of hemosiderin deposition, calcification, and fibrosis.