Diagnostic Ultrasound - Abdomen and Pelvis

Splenic Tumors
TERMINOLOGY
Definitions
• Space occupying benign or malignant tumor(s) of spleen
IMAGING
General Features
• Best diagnostic clue
○ Solitary or multiple, solid or cystic splenic masses
• Key concepts
○ Classification based on pathology and histology; overlap
of imaging appearances
○ Benign tumors
– Hemangioma, hamartoma, lymphangioma, littoral cell
angioma
○ Hemangioma
– #1 primary benign neoplasm of spleen (up to 14%)
– Typically small, incidental, asymptomatic
– Multiple in diffuse splenic hemangiomatosis or
syndromes (Klippel-Trenaunay-Weber and Beckwith-
Wiedemann syndrome)
○ Hamartoma
– Rare; incidentally detected at autopsy or imaging; no
age/gender predilection
– Contains anomalous mixture of normal elements of
splenic tissue
– Syndromic associations: Tuberous sclerosis and
Wiskott-Aldrich syndrome
○ Lymphangioma
– Rare; most occur in childhood; variable size
– Uni- or multilocular; typically subcapsular in location
– Solitary or multiple (as in systemic lymphangiomatosis)
○ Littoral cell angioma (LCA)
– Rare 1° vascular tumor; commonly considered benign,
though malignant LCAs have been reported
– Solitary or multiple; usually presents with
splenomegaly, hypersplenism
○ Malignant tumors
– Lymphoma, leukemia, myeloproliferative disorders
– Metastases
– Rare 1° splenic malignancies: Angiosarcoma,
leiomyosarcoma, malignant fibrous histiocytoma
○ Lymphoma
– #1 malignant tumor of spleen: Hodgkin disease (HD)
and non-Hodgkin lymphoma (NHL)
– Spleen: Nodal organ in HD and extranodal organ in
NHL
– Manifest: Focal lesions (> 1 cm) or diffuse (typical)
– Primary splenic lymphoma: Typically NHL (B-cell origin)
○ Metastases
– Relatively uncommon; may be multiple (60%), solitary
(31%), nodular, and diffuse (9%)
– Common route: Hematogenous spread (splenic
artery)
□ Retrograde (less common): Via splenic vein and
lymphatics
□ Direct extension (uncommon): From gastric, renal,
pancreatic, colonic
– Common primary sites for splenic metastases: Breast
(21%), lung (18%), ovary (8%), stomach (7%),
melanoma (6%), prostate (6%)
– "Cystic" splenic metastases: Melanoma;
adenocarcinoma of breast, ovary, and endometrium
○ Angiosarcoma
– Very rare malignant tumor of spleen; seen in patients
with previous exposure to Thorotrast
– Poor prognosis with early, widespread metastases
Ultrasonographic Findings
• Grayscale ultrasound
○ Benign tumors
○ Hemangioma
– Typically well defined, hyperechoic
– Echogenicity can be variable (range from solid to cystic
to mixed); ± calc when complex
– Rarely, can be large and involve entire spleen with
atypical features: Heterogeneous echotexture, areas
of necrosis and hemorrhage
○ Hamartoma
– Typically well defined, homogeneous, hyperechoic
– Depending on histologic subtype, echogenicity and
vascularity can be variable; can have cystic component
or calc
○ Lymphangioma
– Normal or enlarged spleen depending on number,
size, loculations
– Well-defined hypoechoic mass ± internal septations
and intralocular debris; ± wall calc
– Avascular on color Doppler, unless along cyst walls
○ Littoral cell angioma
– Variable echogenicity and vascularity; solitary or
multiple; splenomegaly
○ Malignant tumors
○ Lymphoma
– US pattern corresponds to 3 macroscopic patterns;
diffuse/infiltrative, miliary/nodular, focal hypoechoic
– "Indistinct boundary" echo pattern
– Anechoic/mixed echoic, small or large nodules;
hyperechoic lesion uncommon (< 10%)
– Lymphadenopathy: Abdominal or retroperitoneal
○ Leukemia and myeloproliferative disorders
– Diffuse enlargement of spleen with variable
echogenicity, very rarely focal hypoechoic nodular
lesions
○ Metastases
– Multiple focal lesions with variable size and
appearance; iso-/hypo-/hyperechoic
– "Target" lesions with hypoechoic "halo"
○ Angiosarcoma: Very rare, solid, mixed echogenicity
mass; associated metastasis in liver (70%)
CT Findings
• Benign tumors
○ Hemangioma
– Homogeneous, hypodense, solid or cystic masses
– Concentric rim of C+ with uniform delayed fill-in;
classic "peripheral nodular C+" associatedwith liver
hemangioma is less common in spleen
○ Hamartoma
Diagnoses: Spleen
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