Diagnostic Ultrasound - Abdomen and Pelvis

Approach to Splenic Sonography
splenic hilum or at midline, arising from the celiac axis.
Intrasplenic vascularity may also be assessed.
In the event that a focal splenic abnormality is identified, it is
critical to document the cystic or solid nature of the lesion, the
echogenicity relative to normal parenchyma, singularity or
multiplicity, and the presence or absence of vascularity (by
color &/or power Doppler techniques).
Supplemental Findings
The spleen may serve as an acoustic window to visualize the
pancreatic tail. Masses of the pancreatic tail may be intimately
associated with the splenic hilum, and the origin of masses in
this location may be difficult to distinguish by ultrasound
alone. Accessory spleens (splenules) may also be located at
the splenic hilum or be closely associated to the pancreatic
tail.
In certain scenarios, a thorough ultrasound exam should
assess for supplemental findings that can add diagnostic
value. Take, for example, a scenario in which diffuse
splenomegaly is incidentally detected. The presence of
enlarged lymph nodes when scanning the upper abdomen or
retroperitoneum in the setting of splenomegaly could help
make the diagnosis of lymphoma. If cirrhosis were suspected
as the cause of splenomegaly, it would be important to
evaluate the patency and flow direction of the splenic vein
and assess for other stigmata of portal hypertension, such as
splenorenal varices or ascites.
Sonographic Work-Up
Ultrasound is a cost-effective and safe initial imaging test to
evaluate the spleen, particularly for splenic size and the
presence of focal splenic lesions. However, because there is
significant overlap in the sonographic appearance of both
benign and malignant splenic lesions, further imaging work-up
with CT, MR, or PET may often be needed. Even with these
imaging tests, the findings may remain nonspecific and
additional work up with tissue sampling could be necessary to
arrive at a diagnosis. It is important to make use of all available
demographic, historical, and laboratory data when developing
a differential diagnosis for splenic abnormalities.
Ultrasound is also useful in the rapid assessment of splenic
injury (focused assessment with sonography for trauma [FAST]
exam) in the setting of blunt abdominal trauma. Bedside
ultrasound is particularly adept in assessing for subcapsular,
perisplenic, or other intraperitoneal hemorrhage.
Hemodynamically unstable patients with a positive FAST exam
are typically taken directly to the operating room for
emergent laparotomy. However, contrast-enhanced CT
remains the imaging gold standard in the grading of splenic
laceration and a negative bedside ultrasound does not
exclude intraparenchymal splenic injury.
Differential Diagnosis
Most lesions that are incidentally seen in the spleen are
benign, with the vast majority representing either cysts or
benign tumors (including hemangiomas, lymphangiomas, or
hamartomas.) The most common splenic malignancy is
lymphoma, followed by metastasis. Primary non-hematologic
splenic malignancies are very rare and may arise from vascular
or other mesenchymal elements; the most common of these
is angiosarcoma.
Benign Splenic Lesions
Benign splenic lesions are very common. Depending on
imaging appearance, the following may be considered as
potential etiologies.
• Acquired cyst: Most common splenic cyst
• Congenital (epidermoid) cyst
• Abscess (pyogenic, fungal, parasitic, granulomatous)
• Infarct
• Hematoma/laceration
• Granuloma (tuberculosis, histoplasmosis, sarcoidosis)
• Gamna-Gandy bodies
• Hamartoma
• Littoral cell angioma(s)
• Peliosis
Malignant Splenic Lesions
Compared to benign lesions, malignant splenic lesions are
relatively uncommon. In the proper clinical setting, however,
malignant entities should be considered.
• Lymphoma: Most common malignant splenic tumor
• Metastasis
• Rare primary splenic neoplasms: Angiosarcoma,
fibrosarcoma, malignant fibrous histiocytoma,
leiomyosarcoma
Diffuse Splenic Enlargement
The spleen is considered to be enlarged when it measures >
13 cm in length. The following may be considered as possible
etiologies for splenomegaly.
• Congestive: Cirrhosis with portal hypertension, heart
failure, splenic vein thrombosis, sickle cell sequestration
• Neoplasm: Leukemia, lymphoma, metastases, primary
neoplasm, Kaposi sarcoma
• Storage disease: Gaucher, Niemann-Pick, amyloidosis,
hemosiderosis, histiocytosis
• Infection: HIV, mononucleosis (Ebstein-Barr virus),
Cytomegalovirus (CMV), hepatitis, malaria, tuberculosis,
typhoid, kala-azar, schistosomiasis, brucellosis
• Hematologic: Hemoglobinopathy, hereditary
spherocytosis, thrombocytopenic purpura, polycythemia
• Extramedullary hematopoiesis: Osteopetrosis,
myelofibrosis
• Collagen vascular disease: Systemic lupus
erythematosus, rheumatoid arthritis (Felty syndrome)
Selected References
1. Nishijima DK et al: Does this adult patient have a blunt intra-abdominal
injury? JAMA. 307(14):1517-27, 2012
2. Benter T et al: Sonography of the spleen. J Ultrasound Med. 30(9):1281-93,
2011
3. Parulekar SG et al. Ultrasound Measurements of the Spleen. In Goldberg BB
et al. Atlas of Ultrasound Measurement.Philadelphia:Mosby, Inc. 439-442,
2006
4. Giovagnoni A et al: Tumours of the spleen. Cancer Imaging. 5:73-7, 2005
5. Middleton WD et al. Ultrasound: The Requisites.Philadelphia: Mosby, Inc.
209-219, 2004
Diagnoses: Spleen
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