Diagnostic Ultrasound - Abdomen and Pelvis

Splenomegaly
Diagnoses: Spleen
○ Hypersplenism: Injected RBCs exhibit shortened half-life
(average of 25-35 days)
• Tc-99m sulfur colloid scan: Measure of splenic function
Imaging Recommendations
• Best imaging tool
○ Ultrasound fast, safe, and reliable for confirmation of
SMG; can detect focal lesions, assess SV patency, and
direction of flow
○ CT most accurately determines spleen size/volume,
allows for characterization of some lesions; MR preferred
for siderosis
• Protocol advice
○ Best visualized following deep inspiration with patient in
right lateral decubitus position
○ Splenic vein assessed at splenic hilum or at midline,
posterior to pancreatic body
DIFFERENTIAL DIAGNOSIS
Splenomegaly Without Focal Mass
• Portal hypertension (cirrhosis)
• Infection (mononucleosis, Salmonella typhi)
• Lymphoma
• Leukemia and myeloproliferative disorders
Solitary Splenic Masses
• Large splenic abscess
○ Irregular wall, well defined, hypoechoic to anechoic
depending on degree of liquefaction and necrosis
• Benign primary tumor
○ Hemangioma
– Solid, echogenic mass ±cystic component;central
punctate or peripheral calcification
○ Lymphangioma
– Thin-walled & hypoechoic; variable vascularity;usually
subcapsular in location; ± calcification
• Malignant primary tumor
○ Lymphoma (Hodgkin or non-Hodgkin lymphoma)
– 1% of all lymphomas; can invade capsule and extend
beyond spleen
– Pattern: Diffuse SMG or focal hypoechoic lesions (no
posterior acoustic enhancement)
○ Primary vascular tumors
– All rare; angiosarcoma most common; littoral cell
angioma
• Secondary malignancy
○ Large, solitary metastasis or lymphoma deposit
PATHOLOGY
General Features
• Etiology
○ Congestive SMG: Cirrhosis with portal hypertension,
heart failure, SV thrombosis, sickle cell sequestration
○ Neoplasm: Leukemia, lymphoma, metastases, primary
neoplasm, Kaposi sarcoma
○ Storage disease: Gaucher, Niemann-Pick, amyloidosis,
hemosiderosis, histiocytosis
○ Infection: HIV, mononucleosis (EBV), CMV, hepatitis,
malaria, TB, typhoid, kala-azar, schistosomiasis,
brucellosis
○ Hematologic: Hemoglobinopathy, hereditary
spherocytosis, thrombocytopenic purpura, polycythemia
○ Extramedullary hematopoiesis: Osteopetrosis,
myelofibrosis
○ Collagen vascular disease: Systemic lupus
erythematosus, RA (Felty syndrome)
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Enlarged spleen by physical exam; unreliable compared
to imaging
○ Signs & symptoms related to underlying cause
○ Variable presentation: Asymptomatic, abdominal fullness
and discomfort, dragging pain
• Lab data: Abnormal complete blood count, liver function
tests, antibody titers, cultures, or bone marrow biopsy
Natural History & Prognosis
• Complications
○ Splenic rupture can occur spontaneously or following
minor trauma (as in athletes)
• Hypersplenism: Usually develops as a result of SMG
○ Hyperfunctioning spleen removes normal RBC, WBC,
and platelets from circulation
• Prognosis
○ Depends on underlying disease
Treatment
• Treatment directed at underlying condition
• Splenectomy in symptomatic & complicated cases
DIAGNOSTIC CHECKLIST
Consider
• SMG most common cause of LUQ mass
• Usually manifestation of systemic disease, rather than
primary splenic pathology
Image Interpretation Pearls
• Is SMG present by size measurements?
• Is SMG diffuse or related to space-occupying lesions?
• Any other clues to underlying cause?
• US great for spleen size; can distinguish between diffuse
SMG or focal abnormality, can assess SV patency and flow
direction
• CT & MR can further characterize abnormalities
SELECTED REFERENCES
1. Chiorean L et al: Ultrasonography of the spleen. Pictorial essay. Med
Ultrason. 16(1):48-59, 2014
2. Benter T et al: Sonography of the spleen. J Ultrasound Med. 30(9):1281-93,
2011
3. Spielmann AL et al: Sonographic evaluation of spleen size in tall healthy
athletes. AJR Am J Roentgenol. 184(1):45-9, 2005
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