Diagnostic Ultrasound - Abdomen and Pelvis

Splenomegaly
Diagnoses: Spleen
IMAGING
• No universal consensus on SMG cut off due to variability in
normal adult spleen size
• SMG is diagnosed when length > 13 cm; additional
measurements of thickness > 5 cm or width > 8 cm may
also be used
• Splenic index (product of length, thickness, and width):
Normally 120-480 cm³; SMG considered index > 500 cm³
TOP DIFFERENTIAL DIAGNOSES
• Splenomegaly without focal mass
○ Portal hypertension (cirrhosis)
○ Infection (mononucleosis, Salmonella typhi)
○ Lymphoma (Hodgkin or non-Hodgkin lymphoma)
○ Leukemia and myeloproliferative disorders
○ Hematologic disorders (hemoglobinopathy, TTP)
○ Storage diseases (Gaucher, hemosiderosis)
• Solitary splenic masses
○ Large splenic abscess
KEY FACTS
○ Hemangioma
○ Lymphangioma
○ Primary malignancy (e.g., lymphoma, angiosarcoma)
○ Metastasis
PATHOLOGY
• Myriad etiologies of SMG; systemic vs. primary splenic, focal
lesion(s) vs. diffuse enlargement
DIAGNOSTIC CHECKLIST
• Is SMG present by size measurements?
• Is SMG diffuse or related to space-occupying lesions?
• Any other clues to underlying cause?
• SMG usually manifestation of systemic disease, rather than
primary splenic pathology
• US best initial test; very useful for estimating spleen size;
can distinguish between diffuse SMG or focal abnormality,
can assess SV patency and flow direction
(Left) US in a 47-year-old man
with hepatitis C cirrhosis and
splenomegaly (length 13.5 cm,
thickness 6.5 cm) shows the
dilated, tubular anechoic
structures at the splenic hilum,
consistent with splenic varices
ſt. Echogenic foci without
posterior acoustic shadowing
throughout the spleen
represent Gamna-Gandy
bodies . (Right) Color
Doppler in the same patient
confirms dilated splenic hilar
varices in this patient with
portal hypertension.
(Left) US in a 47-year-old man
shows splenomegaly (length
19.5 cm) due to spaceoccupying
hypoechoic masses
st, without internal
vascularity (not pictured).
These represented splenic
abscesses. (Right) Axial CECT
in the same patient
demonstrates large, lobulated,
hypodense splenic lesions
resulting in splenomegaly. Pus
was revealed on percutaneous
drain placement, consistent
with splenic abscess.
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