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Large Splenic Masses: Key Imaging Findings for Reaching a Diagnosis

Elliot K. Fishman MD FACR
Linda C. Chu MD
Satomi Kawamoto MD

Johns Hopkins Hospital

Although we agree that most incidental Splenic lesions are benign and are leave alone lesions as lesions get larger (5 cm or greater) the challenge of ”leaving a lesion alone” gets more difficult. We present some key findings that we feel are helpful with these often challenging cases.

“In conclusion, in patients with an incidental splenic mass identified at imaging and with the absence of a history of malignancy, fever, weight loss, or pain in the left upper quadrant or epigastrium, such masses are highly likely to be benign regardless of their appearance. Additional imaging or follow-up is not warranted, even if the mass does not show the appearance of a simple cyst. Further work-up is only needed if the splenic mass is seen in conjunction with other findings worrisome for malignancy.”
The Incidental Splenic Mass at CT: Does It Need Further Work-up? An Observational Study
Siewert B et al.
Radiology 2018; 287:156–166

Large Splenic Masses: Key Imaging Findings for Reaching a Diagnosis

Solitary vs multiple lesions
Solid vs cystic mass
Sharply defined vs ill defined masses
Lesion enhancement (hypovascular or hypervascular or no enhancement)
Lesion calcification (central vs peripheral calcification)
Lesion relationship to splenic margins including shape changes of spleen. Is the spleen enlarged?
Extra splenic findings (hepatic or renal lesions, adenopathy, ascites, lung nodules or mediastinal adenopathy)

Large Splenic Masses: Key Imaging Findings for Reaching a Diagnosis

Solitary vs multiple lesions
Lesion enhancement (hypovascular or hypervascular or no enhancement)
Lesion calcification (central vs peripheral calcification)
Lesion relationship to splenic margins including shape changes
Extra splenic findings (hepatic or renal lesions, adenopathy, ascites)

Solitary vs multiple lesions: Factoids

In most cases a lesion that is a solitary mass has a significantly different differential diagnosis than a lesion that has multiple masses.
Solitary lesions are often benign (cysts, hemangioma, hamartoma) although primary and metastatic lesions to the spleen can be solitary
Benign lesions tend to have sharper margins than malignant lesions
Benign lesions are at times difficult to diagnosis and be confused with a malignant mass

Splenic Lesion Evaluation Parameters

Is the lesion solitary or multiple?
Is the lesion attenuation cystic (0—0 HU) or solid (30-70 HU)?
Does the lesion enhance with IV contrast or does it remain stable (less then 10HU enhancement)?
If the lesion enhances is it hypervascular and what are its boundaries (well defined vs irregular)?

Splenic Lesion Enhancement: Key Findings

Non-enhancement of the lesion-classic lesions in this category are splenic cysts
Hypervascular lesion- hamartomas are very vascular as are malignancies like the rare angiosarcoma. Hemangiomas can have peripheral enhancement
Hypovascular lesion- hemangiomas are often hypovascular as are metastases as well as lymphoma

Splenic Cysts are water density with sharp margins. Splenic cysts can be large and multiple though in most cases splenic cysts are small in caliber.

Large Splenic Masses

Splenic cysts are a good example of being able to recognize a benign lesion regardless of its size. The lesions are well defined and measure 0-10 HU. Splenic cysts are commonly multiple. Multiple splenic lesions can be seen in sarcoidosis, metastases, lymphoma and hemangioma.

Large Splenic Masses

Puddling of the Lesion is classic for hemangioma. The lesion also has lobulated margins. Most splenic hemangiomas do not have this classic enhancement pattern.

Large Splenic Masses

The radiological imaging studies like magnetic resonance imaging (MRI) and computed tomography scan (CT scan) have not proven to be adequate in diagnosing littoral cell angioma, given that it is difficult to differentiate from other splenic neoplasms like angiosarcomas, lymphomas, metastatic tumors on imaging

Large Splenic Masses

Angiosarcoma of the Spleen is uncommon but is usually hypervascular with multifocal disease with poor margins. Ascites is common.

Large Splenic Masses

“On CT scans, the most common finding is an ill-defined heterogeneously enhancing splenic mass with areas of necrosis. In the event of acute rupture, hemorrhage will appear hyperattenuated on unenhanced images. There is no particular pattern of calcification associated with splenic angiosarcoma, but areas of hypervascular metastases to the liver, lungs, bones, and lymphatic system are well demonstrated on CT.”
Primary Splenic Angiosarcoma
Kamran S. Hamid et al.
JSLS. 2010 Jul-Sep; 14(3): 431–435.

Large Splenic Masses

Splenic Lesion Shape: Key Findings

Well defined and sharp margins- sharp margins are common in benign lesions like hemangioma, hamartoma, hepatic cysts and occasionally metastases. Hamartomas often bulge the splenic margins and well seen on arterial and venous phase imaging
Poorly defined margins- poor margins are seen in lesions like lymphoma and abscesses

Epithelial Cyst Spleen Compresses Tail of Pancreas

Splenic Hemangioma

Splenic Hamartoma shows the bulge of the mass which is vascular and isodense on venous phase imaging

Large Splenic Masses

Splenic Hamartoma is vascular and bulges the boundaries of the spleen.

Large Splenic Masses

Metastatic ovarian cancer to the spleen shows a hypodense mass with mild enhancement with irregular margins and a mottled enhancement pattern

Large Splenic Masses

Large splenic mass which is hypovascular with irregular margins. Mass also seen in pancreatic head making the diagnosis likely to be B-Cell Lymphoma

Large Splenic Masses

B-Cell Lymphoma involves the Spleen and Liver with adenopathy. The splenic mass is best seen on the venous phase images.

Large Splenic Masses

Splenic Lymphoma with Adenopathy. Splenic mass is hypodense and infiltrative. The margins are poorly defined.

Large Splenic Masses

Splenic Lymphoma Involves the Pancreas as well as para-aortic adenopathy.

Large Splenic Masses

The role of cinematic rendering for the evaluation of splenic pathology may prove valuable by looking at the texture analysis of the splenic lesion. The solid mass with infiltration is nicely defined.

Large Splenic Masses

Splenic Enlargement for Focal Infiltration (vs mass)

Diffuse enlargement of the spleen can occur without a defined splenic mass but with changes in enhancement pattern.
Diffuse enlargement but with patchy or mottled enhancement is a good sign of malignancy with tumor infiltration

Primary Splenic Lymphoma

Pearl: Critical CT Parameters Include Lesion Attenuation and Enhancement and Margins

Primary Splenic Lymphoma

Kaposi’s Sarcoma Involves Spleen and Liver

Pearl: Patterns of Enhancement Consistent with malignancy

Kaposi’s Sarcoma Involves Spleen and Liver

Inflammatory Pseudotumor of the Spleen has the appearance of a malignant tumor but is a rare diagnosis.

Large Splenic Masses

Pearl

”The definitive diagnosis is established with the histological findings, characterized by the presence of inflammatory cells with areas of necrosis and fibrosis. There are multiple differentials diagnoses: metastasis, lymphoma, splenic infarction, hemangiomas, vascular malformations, lymphangioma, plasmacytoma, reactive lymphoid hyperplasia, abscess and infectious granulomatous processes; therefore suspicion of malignant neoplasm must be considered, being indicated splenectomy to confirm the diagnosis.”
Inflammatory pseudotumor of spleen: a case report.
Ugalde P et al.
Int J Surg Case Rep. 2015;7C:145‐148.

Splenic Mass is a global splenic infarct simulating a mass

Splenic infarct is usually easy to diagnose and is wedged shaped in appearance. When there is a global infarction it may at first glance simulate a mass or infiltrating tumor.

Splenic Mass is a global splenic infarct simulating a mass

Adenocarcinoma Pancreas Recurrence with Splenic Infarction

“Lymphoma can infiltrate the spleen diffusely, causing splenomegaly, or can present as discrete nodules or masses. Necrosis of lymphoma is rare. Infarction of the spleen involved by lymphoma can occur. On ul- trasound, discrete lesions are usually hypoechoic and on CT, lesions are low attenuation, which are best seen on portal venous phase images.”
Nonneoplastic, Benign, and Malignant Splenic Diseases: Cross-Sectional Imaging Findings and Rare Disease Entities
Thipphavong S et al.
AJR 2014;203: 315-322

CLL Involves Spleen with Splenic Bleed

Splenic Abscess have irregular margins and are hypodense with air bubbles seen in less than 20% of cases.

Large Splenic Masses

Marked splenomegaly has a different differential diagnosis and a range of pathologic processes which are another challenge but beyond the scope of this presentation.

Large Splenic Masses

Summary and the Last Word

Although most large splenic lesions are benign the pathology that involves the spleen ranges from cysts to abscesses to hamartomas to lymphoma. By analyzing each lesion and looking at other imaging findings beyond the spleen when present one can reach a correct diagnosis in most cases. We hope this review is valuable for you everyday practice.

References

Siewert B, Millo NZ, Sahi K, et al. The Incidental Splenic Mass at CT: Does It Need Further Work-up? An Observational Study. Radiology. 2018;287(1):156-166. doi:10.1148/radiol.2017170293
Bhutiani N, Egger ME, Doughtie CA, et al. Intrapancreatic accessory spleen (IPAS): A single-institution experience and review of the literature. Am J Surg. 2017;213(4):816-820. doi:10.1016/j.amjsurg.2016.11.030
Warshauer DM, Hall HL. Solitary splenic lesions. Semin Ultrasound CT MR. 2006;27(5):370-388. doi:10.1053/j.sult.2006.06.003
Rowe SP, Chu LC, Fishman EK. 3D CT cinematic rendering of the spleen: Potential role in problem solving. Diagn Interv Imaging. 2019;100(9):477-483. doi:10.1016/j.diii.2019.03.005
Ahmed S, Horton KM, Fishman EK. Splenic incidentalomas. Radiol Clin North Am. 2011;49(2):323-347. doi:10.1016/j.rcl.2010.11.001