Diagnostic Ultrasound - Abdomen and Pelvis

Splenic Cyst
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Diagnoses: Spleen
Neoplastic
• Benign: e.g., hemangioma & lymphangioma
○ Hemangioma
– Variable size and echogenicity, solid ± cystic areas,
rarely solitary large lesion involving entire spleen
○ Lymphangioma
– Heterogeneous/multicystic appearance, intracystic
echoes: Proteinaceous material
• Malignant: e.g., lymphoma & metastases
○ Lymphoma
– Hypoechoic/anechoic type of lymphomatous nodules:
May resemble cysts, however reveal "indistinct
boundary" echo pattern
– Posterior acoustic enhancement absent
○ Metastases: Necrotic/cystic
– Relatively common; e.g., malignant melanoma,
adenocarcinoma of breast, pancreas, ovaries, and
endometrium may cause "cystic" splenic metastases
– Multiple focal, cystic lesions of variable size
Vascular
• Hematoma or laceration
○ Hypo-/iso-/hyperechoic, blood-filled cleft; nonspherical
shape
○ Hematoma echogenicity depends on stage of bleed;
fresh blood echo-free initially, later becomes echogenic
○ End stage: Cystic degeneration →pseudocyst
• Infarction (arterial or venous)
○ Acute phase: Well-defined, wedge-shaped areas of
decreased echogenicity
○ Subacute & chronic phases: Anechoic (due to liquefactive
necrosis)
• Peliosis
○ Rare; usually with liver findings; multiple indistinct areas
of hypo-/hyperechogenicity that may involve entire
spleen
• Intrasplenic pseudoaneurysm
○ Post-traumatic; anechoic on grayscale, fills with color
Doppler
Intrasplenic Pancreatic Pseudocyst
• In 1-5% of patients with pancreatitis
• Direct extension of pancreatic pseudocyst; pancreatic
secretions extend along splenic vessels to hilum, pancreatic
enzymes cause erosion into spleen
• Well-defined, rounded, cystic splenic lesion; associated
inflammatory changes of pancreas
PATHOLOGY
General Features
• Etiology
○ Congenital: Genetic defect of mesothelial migration
○ Acquired: Most often post-traumatic, end-stage of
splenic hematoma/infarction
– Pathogenesis: Liquefactive necrosis, cystic change
Gross Pathologic & Surgical Features
• Congenital cyst
○ Usually large, glistening, smooth walls
• Acquired cyst
○ Smaller than true cysts, debris, wall calcification
○ Parasitic: Hydatid (Echinococcus granulosus most
common form to affect spleen), Taenia solium
Microscopic Features
• True cyst: Epithelial lining present
○ Epidermoid (stratified, nonkeratinizing squamous
epithelium), mesothelial (low cuboidal to low columnar),
dermoid (squamous lining with dermal structures)
○ Epidermoid most common
• False cyst: No epithelial lining, may have fibrous capsule
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Depends on etiology, acuity
○ Often asymptomatic
○ Mild pain or tenderness, palpable mass in LUQ,
splenomegaly
Demographics
• Age
○ 2/3 < 40 years old
• Gender
○ M:F = 2:3
Natural History & Prognosis
• Complications: Hemorrhage, rupture, infection
• Prognosis
○ Good: Uncomplicated cases; after surgical removal
○ Poor: Complicated cases
Treatment
• Symptomatic: Surgery (total cystectomy, marsupialization,
cyst decapsulation, or partial/total splenectomy)
• Asymptomatic
○ Small: No treatment
○ Large (> 5-6 cm): Surgical removal (controversial)
• Ultrasound-guided drainage ± injection of sclerosing agent
is alternative option
DIAGNOSTIC CHECKLIST
Consider
• Rule out infectious, vascular, and neoplastic cystic lesions
Image Interpretation Pearls
• Congenital: Larger, well defined, anechoic, thin wall; ±
calcification and debris (less common)
• Acquired: Usually smaller, well defined; often anechoic with
thicker wall; ± calcification, ± debris
• Often impossible to distinguish primary vs. secondary (or
true vs. false) cysts by imaging
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. Li W et al: Real-time contrast enhanced ultrasound imaging of focal splenic
lesions. Eur J Radiol. 83(4):646-53, 2014
3. Caremani M et al: Focal splenic lesions: US findings. J Ultrasound. 16(2):65-
74, 2013