Spleen (PBR 2)

Question 1

This finding may be formed during the arciform enhancement phase on postcontrast CT and MR

Answer 1

Transient pseudomass

Irregular defects in parenchymal enhancement may closely simulate splenic lesions

One or 2 minutes later, the entire spleen becomes homogeneously enhanced.

Question 2

Imaging finding of accessory spleens

Answer 2

Appear as round masses, 1 to 3 cm in size, and of the same imaging features as normal splenic parenchyma

They may be single or multiple and are usually located near the splenic hilum

Question 3

Term applied to a normal spleen positioned outside of its normal location in the left upper quadrant

Answer 3

Wandering spleen

Laxity of the splenic ligaments, commonly found in association with abnormalities of intestinal rotation, allows the spleen to be positioned anywhere in the abdominal cavity

Question 4

How do one diagnose a wandering spleen?

Answer 4

Recognizing the normal shape and tissue texture of the spleen
Noting the absence of normal spleen in the left upper abdomen
Identifying the blood supply from splenic vessels

Radionuclide scans confirm functioning splenic tissue

Question 5

This refers to multiple implants of ectopic splenic tissue that may occur after traumatic splenic rupture

Answer 5

Splenosis

Splenic tissue can implant anywhere in the abdominal cavity, or even in the thorax if the diaphragm has been ruptured

Question 6

Process that happens after splenectomy:
The remaining accessory spleens, or splenules resulting from traumatic peritoneal seeding of splenic tissue may enlarge and resume the function of the resected spleen

Answer 6

Splenic regeneration

When the spleen is removed, bits of nuclear material, called Howell–Jolly bodies, are routinely seen in red cells on peripheral blood smears

Absence or disappearance of these Howell–Jolly bodies from peripheral blood is a clinical sign of splenic regeneration.

Question 7

This is a rare congenital anomaly that features multiple small spleens, usually located in the right abdomen and associated with situs ambiguous

Both lungs are two-lobed

Most patients also have cardiovascular anomalies

Answer 7

Polysplenia

Question 8

Also known as Ivemark syndrome

This is s the congenital absence of the spleen, found in association with bilateral right-sidedness, midline liver, and bilateral three- lobed lungs

Answer 8

Asplenia

Question 9

Imaging findings that suggest splenomegaly

Answer 9

1. Any spleen dimension greater than 14 cm
2. Projection of the spleen ventral to the anterior axillary line
3. Inferior spleen tip extending more caudally than the inferior liver tip
4. Inferior spleen tip extending below the lower pole of the left kidney

Enlarged spleens frequently compress and displace adjacent organs, especially the left kidney

Question 10

Most common malignant tumor INVOLVING the spleen

Answer 10

Lymphoma

Either as primary splenic lymphoma or as part of systemic disease

Question 11

Patterns of splenic lymphoma

Answer 11

1. Diffuse splenomegaly
2. Multiple masses of varying size
3. Miliary nodules resembling microabscesses
4. Larger solitary mass
5. Direct invasion from adjacent lymphomatous nodes

Question 12

Lymphoma is a common predisposing condition for splenic infarction

True or false?

Answer 12

True

Question 13

What are the most common tumors that metastasize to the spleen?

Answer 13

1. Malignant melanoma (cystic)
2. Lung carcinoma
3. Breast carcinoma
4. Ovary carcinoma
5. Prostate carcinoma
6. Stomach carcinoma

Question 14

Causes of splenic infarction

Answer 14

1. Emboli 
(from endocarditis, atherosclerotic plaques, or cardiac valve thrombi)
2. Sickle cell disease
3. Pancreatitis
4. Pancreatic tumors
5. Arteritis

Additional predisposing conditions include myeloproliferative disorders, hemolytic anemias, and sepsis

Question 15

Key finding in splenic infarction

Answer 15

Extension of the abnormal parenchymal zone to an intact splenic capsule

Question 16

What are the complications of splenic infarctions

Answer 16

1. Subcapsular hematoma
2. Infection
3. Splenic rupture with hemoperitoneum

Question 17

These are also called siderotic nodules

These are small foci of hemosiderin resulting from focal hemorrhages in the spleen caused by portal hypertension

Answer 17

Gamma-Gandy bodies

Question 18

Most common primary neoplasm of the spleen

Answer 18

Hemangioma

Question 19

Imaging finding of splenic hemagioma?

Answer 19

US - Well-defined hyperechoic mass
CT - Solid and may have central punctate or peripheral curvilinear calcification
MR - Low intensity on T1 and high on T2

Question 20

Most common malignancy arising from the spleen

Answer 20

Angiosarcoma

The tumor is aggressive, usually presenting with widespread metastases, especially to the liver

One-quarter of the cases present with spontaneous splenic rupture.

Question 21

These are false cyst with fibrous walls that lack an epithelia lining

The result from previous hemorrhage, infarction, or infection

Account for 80% of all splenic cysts

Answer 21

Posttraumatic cysts

The walls are thick and commonly become calcified (30% to 40%)

Question 22

These are true epithelial-lined cysts that are probably developmental in origin

They have the same appearance as posttraumatic cysts but less frequently have calcification in their walls (5%)

Most are found incidentally in asymptomatic individuals

Answer 22

Epidermoid cysts

Question 23

These are collections and pseudocysts extend beneath the splenic capsule by tracking along the pancreatic tail to the splenic hilum

Answer 23

Pancreatic fluid

Splenic subcapsular pancreatic fluid collections develop in 1% to 5% of patients with pancreatitis

Internal debris and hemorrhage are commonly present

Imaging studies demonstrate associated findings of pancreatitis

Question 24

Causes of splenic bacterial abscesses

Answer 24

Hematogenous spread of infection (75%)
Trauma (15%)
Infarction (10%)

Question 25

Causes if splenic microabscesses

Answer 25

Found in patients with compromised immune systems attributable to AIDS, organ transplantation, lymphoma, or leukemia

Causes include fungi, tuberculosis, Pneumocystis jiroveci, histoplasmosis, and cytomegalovirus