Ultrasound images of Splenomegaly

Enlargement of the spleen is a highly non-specific sign associated with numerous conditions, the most common being infection, portal hypertension, haematological disorders and neoplastic conditions (Table 6.1). As with the liver, measurement of splenic volume is usually considered inaccurate due to variations in shape, and not reproducible. However, the length of the spleen is an adequate indicator of size for most purposes and provides a useful baseline for monitoring changes in disease status. The length of the normal adult spleen is less than 12 cm.
The spleen enlarges downwards and medially. Its inferior margin becomes rounded, rather than pointed, and may extend below the left kidney (Fig.A). Although the aetiology of splenomegaly may not be obvious on ultrasound, the causes can be narrowed down by considering the clinical picture and by identifying other relevant appearances in the abdomen. Splenomegaly due to portal hypertension, for example, is frequently accompanied by other associated pathology such as cirrhotic liver changes, varices (Fig. B) or ascites. Splenunculi In around 10% of the population, a small accessory spleen, or splenunculus, may be located at the splenic hilum. These small, well-defined ectopic

FIG.A

Ultrasound images Splenomegaly in portal hypertension.
The inferior splenic margin is blunted, descending below
and medial to the left kidney.

FIG.B

Ultrasound images Varices at the splenic
hilum in portal hypertension.

fig. C

Ultrasound images of A splenunculus (arrow) at the hilum of a mildly enlarged spleen.

FIG.D

Ultrasound images The circulation of the splenunculus derives from the main splenic artery and drains into the main splenic vein.

FIG.E

The Ultrasound images left lobe of the liver, LL, extends across the abdomen and above the spleen, S, in hepatomegaly, giving the appearance of a well-defined splenic mass.

Nodules of splenic tissue (Fig. C) rarely exceed 2 cm in diameter. Splenunculi enlarge under the same circumstances as those which cause splenomegaly and may also hypertrophy in postsplenectomy patients. The importance of recognizing these lies in differentiating them from lymph nodes, left adrenal nodules or masses in the tail of pancreas. Colour Doppler may identify the vascular supply as being common to the main spleen1 (Fig. D).