Approach to splenic masses: Clinical sciences

Splenic masses are abnormal growths or tumors of the parenchyma or vasculature of the spleen. They are broadly categorized into solid and cystic lesions. Most splenic masses are benign and incidentally found. The patient’s history and the characteristics of the mass on ultrasound or CT scan are key factors in establishing the diagnosis.

Your first step in evaluating a patient presenting with a chief concern suggestive of a splenic mass is to obtain a focused history and physical examination.

The patient might report a history of night sweats, unintentional weight loss, or fevers. However, keep in mind that some patients might be asymptomatic, in which case their splenic mass was probably discovered incidentally on imaging due to some other concern.

On the other hand, the exam might show left upper quadrant abdominal tenderness, a palpable left upper quadrant abdominal mass, petechiae, or ecchymoses. With these findings you should consider a splenic mass and order imaging like a left upper quadrant abdominal ultrasound or CT scan of the abdomen. These studies will determine if a splenic lesion is present and whether it is cystic or solid.

First, let’s focus on cases where imaging shows cystic splenic masses. These are broadly divided into solitary lesions and multiple lesions.

First up among solitary cystic splenic masses, are epithelial splenic cysts, also known as primary splenic cysts. They got their name because these cysts are lined with epithelial cells. These patients might report vague abdominal pain or fullness, or they may be asymptomatic.

If the ultrasound or CT scan shows a thin-walled fluid-filled structure without internal debris or loculations you can make the diagnosis of epithelial splenic cyst.

On the other hand, you might be dealing with a pseudocyst, also known as a secondary cyst, which are not lined with epithelial cells. These usually occur due to some damage to the spleen like trauma. Therefore, your patient might have a history of trauma or previous splenic infarct.

On ultrasound or CT, you will see a thick-walled cystic structure with rim calcifications. This will lead you to diagnose a splenic pseudocyst.

Next, you might be dealing with a splenic abscess. These patients might have a history of IV drug use or infective endocarditis. On CT you will see a hypodense round fluid collection with rim enhancement. There will be air-fluid levels with or without bubbles. There may also be multiple or complex cysts. With these findings, think splenic abscess.

Lastly, in rare situations, a patient might have an echinococcal or hydatid cyst in the spleen. If this is the case, they may have recently traveled to Central or South America or were exposed to dogs or sheep. On CT you will see multiloculated cysts with daughter cysts with or without eggshell calcifications within the cyst wall. These patients typically have lung or liver lesions as well since splenic lesions are part of a more advanced disease. These findings will lead to the diagnosis of echinococcal or hydatid cyst.

Moving on, let’s talk about multiple cystic splenic masses.

These lesions usually occur in the pediatric population. The ultrasound or CT will likely show multilobulated cysts with thin walls and sharply defined borders. This is characteristic of splenic lymphangiomas.

Alright, now that we have covered cystic splenic masses, let’s turn to solid splenic masses, which can also be subdivided into solitary or multiple lesions.

Solitary solid splenic masses can be vascular or non-vascular in origin. Vascular lesions have a characteristic contrast enhancement on CT from the IV contrast that pools within the mass. Non-vascular lesions, on the other hand, look isodense or hypodense on CT. Let’s talk about vascular lesions first, which include splenic artery aneurysm, hamartoma, hemangioma, and angiosarcoma.

Splenic artery aneurysms occur due to weakening of the arterial wall, which can happen from atherosclerosis or from changes in blood flow dynamic, as seen with portal hypertension and pregnancy. If history reveals portal hypertension, atherosclerosis, or pregnancy, and the CT shows a contrast-enhancing mass continuous with the splenic artery, you can make your diagnosis of a splenic artery aneurysm.