Author: Thomas Ward
Ultrasound CT MRI - T1 MRI - T2 MRI - postcontrast T1 Gross Histology Additional comments and imaging
Benign lesions:
Hemangioma Cystic mass (arrowheads) w/wo internal trabeculation (arrows). Smaller hemangiomas may be echogenic Hypo-attenuating lesion on non-contrast enhanced images, w/wo calcifications.

Progressive enhancement is characteristic.

Delayed images demonstrate a nearly isoattenuating mass, w/wo calcification
Hypointense mass. High signal intensity (arrow) may represent hemorrhage. Variable signal intensity, depending on presence and stage of hemorrhage (arrow). Early post-contrast:peripheral nodular enhancement that progresses centrally.

Delayed post-contrast: uniform (arrow) or progressive internal enhancement.
Hemangioma can be seen to contain a large cystic space (arrows) filled with hemorrhagic debris. H and E stain shows the characteristic multiple blood-filled vascular channels. Cystic areas that were filled with serous material (*) instead of blood. Architectural distortion is noted(arrowheads).
Hamartoma Heterogeneous grey-scale echotexture. Hypervascular on color Doppler. Heterogeneous enhancement Well-defined lesion (arrows), isointense. Areas of hemorrhage (arrowheads) may be present. Irregular, heterogeneously low signal intensity Early post-contrast: mild, diffuse, heterogenous enhancement.

Early post-contrast: mild, diffuse, heterogenous enhancement.

Delayed contrast-enhanced: relative uniform enhancement
Spherical, well-circumscribed, diffusely hemorrhagic mass (arrows) without necrosis. H-E stain: disorganized sinuses and splenic red pulp elements
Lymphatic malformation Multiple, multi-loculated hypo-echoic, rounded lesions. Low-level echoes (arrows) represent proteinaceous fluid. Nonenhancing lesions. May nearly completely replace normal spleen, w/wo calcifications.

Delayed phase: low-attenuation, non-enhancing lesions, w/wocontain calcifications.
Variably sized, low signal intensity. High signal intensity (arrow), indicates proteinaceous material Relatively homogenous hyper-intense signal. Cystic spaces (arrows) containing clear, yellowish fluid consistent with lymph. Septations (arrowheads) can be seen H and E stain: multiple lymph filled channelssurrounded by normal splenic tissue (*)
False Cyst Well-defined, hypoechoic, rounded lesion with a thick wall, possibly calcified (arrowheads). Reverberation artifact is noted (asterisk) Uniform, well-rounded, low attenuation masswith or without a calcified wall Thick fibrous wall outlining a large cyst, variable cyst contents H and E stain: thick wall (double-headed arrow) surrounded by compressed splenic parenchyma (arrow- heads). No epithelial lining.
True cysts Fluid attenuating cystic lesion, w/wo septations

Well-defined, low attenuation mass, w/wo septations
Well defined rounded mass, homogeneous high signal Well-defined, rounded, homogeneously low-signal, non-enhancing lesion (arrow) Large cyst, w/wo thin trabeculae (arrows) H and E stain: trueendotheial lining (arrows)
Peliosis Multiple low-attenuation, lesions of different sizes Multiple low-intensity, rounded lesions of different sizes throughout the splenic and liver parenchyma Diffuse, multiple cystic cavities of variable size with clotted blood H and E stain: hemorrhage within vascular cavities (arrows)
Littoral cell angioma Heterogeneous splenic echotexture, multiple hyperechoic lesions and a focal hyperechoic mass (arrow). Early portal venous phase: multiple, partially confluent hypoattenuating masses

Delayed phase: homogeneously enhance, nearly imperceptible.
Multiple subtle hypointense splenic lesions (arrow). Hypointense (arrow), adjacent to the normally bright splenic parenchyma. Multiple blood-filled spaces (arrow). H and E stain: multiple blood-filled spaces (*) within a focus of littoral cell angioma
Granulomatous disease (Histo, Wegener, Sarcoid) Large necrotic splenic lesions or infiltration with multiple nodules, w/wo scattered calcifications (arrows) Foci of low-signal-intensity may represent calcified granulomatous disease Text soon coming Arterial phase: multiple small, hypointense, lesions. Non- enhancing on the early phase

Delayed phase: Multiple small, hypointense lesions, enhance on delayed phase image
Abscess Heterogeneously hypoechoic mass, internal low-level echoes and irregular borders(arrowheads) Nonenhanced CT: hypoattenuating mass (large arrow), may see adjacent inflammatory changes (small arrow)

Low-attenuation mass, irregular borders(arrows). Extra-splenic spread may be seen
Cystic mass, may demonstrate irregular or thick wall, heterogeneously intermediate signal intensity. Heterogeneous, hyperintense signal intensity Cystic mass, enhancing irregular wall, heterogeneously intermediate signal intensity internally Irregular nodular borders H and E stain: shows severe inflammatory infiltrate and hemorrhage (arrows), destruction of normal splenic tissue
Hematoma Heterogeneous spleen, with multiple hypoechoic collections of blood (arrows) Nonenhanced: increased attenuation compatible with acute or subacute.Chronic may be fluid-attenuating

Contrast-enhanced: single or multiple scattered well-defined low-attenuation.
Depends on hematoma age. Heterogeneous T1 iso- to hyper- intense lesion represents acute/subacute hematoma Depends on hematoma age. Heterogeneous T2 hyper-intense lesion represents acute/subacute hematoma H and E stain: fragments of normal spenic parenchyma (*) and large collections of blood (arrows).
Malignant lesions:
Lymphoma Complex mass, variable echotexture. Ill-defined, central hypoechoic area (*) corresponding to cystic region. Acoustic enhancement accounts for some of the increased echogenicity within this lesion. Venous phase: large, ill-defined mass with low attenuation.

Delayed phase: homogeneously attenuating spleen with a wedge-shaped area of low attenuation (arrow) corresponding to area of infarct.
Delayed phase: homogeneously attenuating spleen with a wedge-shaped area of low attenuation (arrow) corresponding to area of infarct. Variable, hyperintense component secondary to the proteinaceous nature of the necrotic material. In this case, heterogeneously increased signal is secondary to diffuse involvement. Hypovascular, irregular, infiltrative lesion Infiltrating lymphorna (*) with a central cystic/necrotic area (arrowheads). H and E stain: diffuse infiltration (*). A small amount of normal splenic parenchyma (double-headed arrow).
Metastases Hyperechoic mass (arrowheads), depends on primary. Doppler examination may show internal vascular flow. Penitoneal implants from mucinous adenocarcinoma scallop the surface of the liver and spleen.

Contrast-enhanced: large, ill-defined, low-attenuation lesion. Metastatic disease may present as single or multiple splenic lesions
Usually T2-hyperintense, as in this case (renal cell carcinoma, arrows). Large, metastatic foci, ranging from cystic (*) to solid (arrows) Histology depends on primary tumor. H and E stain: neoplastic tissue composed of mucous glands (*), primary colonic adenocarcinoma.
Angiosarcoma Heterogeneous echotexture, echogenic rim (arrow) and a hypoechoic center (arrowhead) compatible with necrosis. Doppler: hypervascular rim Non-enhanced: vague hypo-attenuating lesion (arrow), w/wo calcifications (20%)

Early portal-venous:heterogeneous enhancement, decreased attenuation (arrowhead) corresponds to necrosis. Two enhancing masses (black arrows) are seen in the liver.

Delayed: low attenuation, focal central high attenuation correspons to hemorrhage, w/wo calcifications
Low signal intensity in the periphery (arrows), high signal intensity in the center (hemorrhage). Liver lesions compatible with metastasis High signal intensity in the periphery, inhomogeneity in the center is compatible with necrosis. Liver lesions compatible with metastasis Intense contrast enhancement, w/wo metastasis. Multiple tumor nodules in the periphery of the rim (white arrows) and a central necrosis and fibrosis (black arrows). H and E stain:diffusely infiltrating purple masses (arrowheads) and areas of focal hemorrhage (*).
Other:
Infarction Scattered heterogeneous wedge-shaped and rounded hypoechoic areas with hemorrhagic debris (arrows) Hyperacute infarct: enlarged spleen with generalized decreased attenuation, w/wo hemorrhage

Chronic infarct: small spleen, possibly calcified

Incomplete infarct: focal wedge-shaped lesion

Chronic, incomplete: wedge-shaped, hypoattenuating lesion, w/wo subcapsular splenic calcification
Peripheral area of increased signal intensity with a dark rim, compatible with an infarct. Nonenhancing wedge-shaped area(arrow) Variable, multiple cystic areas with irregular borders Liver-spleen scan: acute sequestration shows only a thin rim of activity (arrowhead)
Trauma Grade 1: Subcapsular hematoma <10% surface area Laceration: Capsular tear, <1 cm parenchymal depth

Grade 2: Subcapsular hematoma 10%50% surface area; intraparenchymal hematoma <5 cm in diameter Laceration 13 cm parenchymal depth; does not involve a trabecular vessel

Grade 3: Subcapsular hematoma >50% surface area or expanding; ruptured subcapsular or parenchymal hematoma Laceration: >3 cm parenchymal depth or involved trabecular vessels

Grade 4: Laceration involving segmental or hilar vessels and producing major devascularization (>25% of spleen)

Grade 5: Laceration completely shattered spleen. Hilar vascular injury, devascularizes spleen, active bleeding (arrows) and extravasation (arrowhead)