Diagnostic Ultrasound - Abdomen and Pelvis

Splenic Tumors
Diagnoses: Spleen
– Isodense (typically) or hypodense;variable early C+;
uniform C+ on delayed scans
○ Lymphangioma
– Low-attenuation lesion(s); sharp margins; typically
subcapsular; no enhancement;± wall calcification
• Malignant tumors
○ Lymphoma
– Solitary, multifocal or diffuse; Hypodense lesions with
minimal enhancement
○ Metastases
– Multiple, solid (common) or cystic, hypodense, central
or peripheral enhancement
○ Angiosarcoma
– Solitary or multiple, irregular margins, heterogeneous
density; variable enhancement;± calcification
– Usually liver or distant metastases
MR Findings
• Benign tumors
○ Hemangioma: T1 ↓, T2 ↑; C+: uniform or
heterogeneous centripetal
○ Hamartoma: T1 iso; T2 hetero; C+: similar to CT
○ Lymphangioma: T1 ↓ or ↑ (depending on protein/blood
content) , T2 ↑↑; No C+
• Malignant tumors
○ Lymphoma
– MR not reliable due to similar T1, T2 relaxation times
and proton densities of spleen/lymphoma
○ Metastases
– T1WI: Isointense to hypointense, T2WI: Hyperintense
– T1 C+: Enhancement depends on type of primary
Nuclear Medicine Findings
• PET/CT
○ 18F-FDG avidity can be a helpful feature to distinguish
between benign and malignant solid splenic lesions
– In patients with known malignancy, SUV > 2.3 can
differentiate benign and malignant with 100%
sens/spec
– High NPV in patients without known malignancy
– False-positives can be due to granulomatous diseases
Image-Guided Biopsy
• Splenic biopsy is gaining increased acceptance
○ Risks include hemorrhage (leading to hypotensive
shock), pneumothorax, or colonic injury
• Ultrasound or CT used; US may be preferred due to real
time assessment of the vessels with color Doppler
• Splenic FNA: Low complication rate but lower success rate
• Splenic core biopsy: Higher diagnostic success rate (> 88%)
but higher complication rate (up to 12% reported)
Imaging Recommendations
• Best imaging tool
○ US initially, CT/MR for further characterization
• Protocol advice
○ Patient is best scanned in supine or right decubitus
position for intercostal acoustic window
DIFFERENTIAL DIAGNOSIS
Splenic Infarct
• Wedge-shaped, well-defined, hyperechoic/hypoechoic area
(depending on the age of infarct), avascular
Splenic Infection/Abscess
• Pyogenic abscess:Solitary or multiple, small or large,
hypoechoic lesions with ± thick irregular walls
• Fungal microabscesses; mycobacterial (TB, MAC)
granulomas: Multiple hypoechoic avascular lesions
Splenic Cyst
• Anechoic/hypoechoic, sharp margins, posterior acoustic
enhancement, ± peripheral rim calcification, avascular
Splenic Hematoma
• Subcapsular of intrasplenic; hyper/hypoechoic (depending
on stage of liquefaction) fluid collection/lesion
Hepatosplenic Sarcoidosis
• Splenic involvement uncommon; SMG; multiple hypoechoic
nodules (or iso/hyper)
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Varies from asymptomatic incidental finding to
symptomatic depending on size, type of tumor
○ Left upper quadrant pain, palpable mass, splenomegaly,
weight loss
Natural History & Prognosis
• Complications: Hemorrhage, rupture
• Prognosis: Good (benign tumors); poor (malignant)
Treatment
• Splenectomy depending on type (can also be diagnostic if
image guided biopsy not possible)
DIAGNOSTIC CHECKLIST
Consider
• 1° splenic malignancies are rare; biggest diagnostic dilemma
is usually an indeterminate splenic lesion in patients with
extrasplenic malignancy (i.e., is it metastasis)
Image Interpretation Pearls
• Considerable overlap in US findings; reliable differentiation
on imaging is not always possible, requires histology
SELECTED REFERENCES
1. Gaetke-Udager K et al: Multimodality imaging of splenic lesions and the role
of non-vascular, image-guided intervention. Abdom Imaging. 39(3):570-87,
2014
2. Thipphavong S et al: Nonneoplastic, benign, and malignant splenic diseases:
cross-sectional imaging findings and rare disease entities. AJR Am J
Roentgenol. 203(2):315-22, 2014
3. Kamaya A et al: Multiple lesions of the spleen: differential diagnosis of cystic
and solid lesions. Semin Ultrasound CT MR. 27(5):389-403, 2006
4. Bachmann C et al: Color Doppler sonographic findings in focal spleen lesions.
Eur J Radiol. 56(3):386-90, 2005
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