Gastrointestinal - Learning Modules - CTisus.com CT Scanning

CT of the Spleen: Interesting Cases

Elliot K. Fishman, M.D.

The Russell H. Morgan
Department of Radiology and Radiological Science
The Johns Hopkins Medical Institutions
Baltimore, Maryland

Problem: The study is done to rule out suspected splenic pathology. The typical history is either FUO, LUQ pain or palpable spleen. The study may also be part of a workup for suspected lymphoma or myeloproliferative disorder. Evaluation of the spleen can also be a focus of evaluation of a patient with sickle cell disease or one of its variants.

Protocol: In most cases except when you are concerned for an aneurysm or pseudoaneurysm an arterial phase adds little to the evaluation of suspected splenic pathology. Therefore in most cases we will do a venous phase with 60-70 delay following injection of 100-120 cc of iodixanol-350. Occassionally a delayed phase at 3-4 minutes may be useful but that is rare. As for arterial phase imaging it would surely be helpful if the mass was vascular but they are usually angiosarcomas and are rare.

Hamartoma: Facts

Rare, occur at any age
anomalous mixture of splenic elements, congenital
usually solitary, but can be multiple
associated with Tuberous Sclerosis

Hamartoma: CT Findings (CT Appearance)

iso or hypodense on non contrast CT
slow enhancement after IV contrast
CT appearance can be similar to hemangioma
Well-defined

Hamartoma

Splenic Hamartoma

“Splenic hamartomas are tumors composed of a varying mixture of tumor tissue and normal splenic tissue, with reported sizes ranging from 0.3 to 20.0 cm. Hamartomas are solid lesions that may contain a cystic or necrotic component. Splenic hamartomas can be associated with syndromes—namely, tuberous sclerosis and Wiskott-Aldrich-syndrome. Two subtypes of splenic hamartomas can occur: white pulp lesions, which are composed of aberrant lymphoid tissue, and red pulp lesions, which are composed of an aberrant complex of sinuses. Most hamartomas are a mixture of the two subtypes.”
Nonneoplastic, Benign, and Malignant Splenic Diseases: Cross-Sectional Imaging Findings and Rare Disease Entities
Thipphavong S et al.
AJR 2014; 203:315–322

Hamartoma

Rare, benign lesion of anomalous red pulp without organized white pulp (lymphoid follicles)
Iso- to hypoattenuating
Delayed enhancement due to slow-flow through red pulp reticular cords

Splenic Hemangioma

"The calcifications within hemangiomas can appear as central punctate, curvilinear, or speckled in areas of thrombosis. Multiphase CT of a splenic hemangioma will typically show a hypoattenuating lesion on unenhanced CT, sometimes with early peripheral discontinuous enhancement with uniform delayed enhancement mirroring the blood pool, although this pattern can be obscured because of background parenchyma enhancement. Smaller lesions may show flash-filling enhancement, especially among the capillary subtype, and larger lesions will often show centripetal progression of enhancement with a persistently enhancing central fibrous scar.”
Calcified Splenic Lesions: Pattern Recognition Approach on CT With Pathologic Correlation
Consul N et al.
AJR 2020; 214:1083–1091

Hemangioma

Hemangiomatosis

Replacement of spleen by multiple hemangiomata
Part of generalized angiomatosis in Klippel-Trenauny-Weber syndrome (KTWS)
Associated with portal venous hypertension
Prone to spontaneous hemorrhage

Lymphangiomatosis

Rare, benign slow-growing neoplasm
Solitary or with rare lymphangiomatous syndrome
Multiple, small hypoattenuating lesions with simple, hemorrhagic or proteinaceous fluid
May have few, enhancing septae; peripheral calcifications rare

Spontaneous Hemorrhage

Inflammatory – Langerhans Cell Histiocytosis (LCH).

Inflammatory – Sarcoidosis

Littoral Cell Splenic Angioma: Facts

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. Owing to the hemosiderin deposits in the tumor cells, hypodense lesions are visible on T1 and T2 weighted MRI images. Sonography evaluation is not helpful because of the variable findings of heterogeneous echotexture and no definite lesions.

Littoral Cell Splenic Angioma: Facts

The differential diagnosis includes other vascular neoplasms of the spleen, including splenic hemangioma, lymphangioma, hamartoma, angiosarcoma. The LCA can be differentiated from these lesions based on the histopathological and immunophenotyping findings, as detailed above. Imaging studies (MRI, CT scan, ultrasound) have not demonstrated usefulness in differentiating between these.

Littoral Cell Angioma

Littoral Cell Angioma in KMS

Littoral cell cells line the vascular channels of the red pulp
Angioma pathologically manifests with multifocal nodules, cystic and sponge-like spaces comprised of anastomosing vascular channels
Associations include splenomegaly, anemia, thrombocytopenia

“Inflammatory pseudotumor of the spleen is a rare benign process with nonspecific CT features. The mass was generally hypodense with delayed enhancement on CT.”
Computed tomographic and clinicopathological features of inflammatory pseudotumor of the spleen.
Lu T, Yang CJ
Comput Assist Tomogr. 2015;39(3):409‐413.

Inflammatory Pseudotumor of the Spleen

Sclerosing Angiomatoid Nodular Transformation (SANT) of the Spleen

Recently recognized
Rare, 30 reported cases
Nonneoplastic vascular lesion
Microscopically, all the reported cases have multiple angiomatoid nodules in a fibrosclerotic stroma
DDX: splenic hamartoma, inflammatory myofibroblastic tumor, littoral cell angioma, and hemangioendothelioma
F»M
Age 22-74 years

Sclerosing Angiomatoid Nodular Transformation (SANT) of the Spleen

Most incidental findings in asymptomatic patients
Some present with abdominal pain or discomfort
Splenomegaly rare
Benign course with splenectomy curative

SANT

Sclerosing Angiomatoid Nodular Transformation (SANT)
Benign, vascular lesion
Angiomatous nodules – early, progressive enhancement
Surrounding fibrous tissue – delayed enhancement with central, sclerosed scar

Splenic Malignancies

Primary tumor
- Lymphoma
- Angiosarcoma
Metastatic disease
- Melanoma
- Lung cancer
- Breast cancer
- Renal cancer

Angiosarcoma Spleen and Liver

Metastatic Ovarian cancer to Spleen

Splenic and Adrenal Metastases from RCC

Melanoma Metastatic to the Liver and Spleen

Metastasis

Metastasis: Facts

35% incidence at autopsy
However MDCT detects only 1.5% - 4.5%
Hypoattenuating

Metastasis can be cystic

Splenic Lymphoma: Facts

Primary Splenic Lymphoma
- most common primary tumor of the spleen
- rare, 1-2 % of all lymphomas
- usually Non-Hodgkin, B cell type
Secondary Splenic Lymphoma
- • Secondary splenic involvement
- common in both Hodgkin and non-Hodgkin lymphoma
- at time of diagnosis, spleen involvement in 25%

B-Cell Lymphoma Spleen

Arterial vs Venous

CLL Infiltrates the Spleen

Lymphoma

Hemangiosarcoma

Aggressive neoplasm; most common, primary hematogenic / non-lymphoid malignancy
May present with spontaneous hemorrhage or visceral rupture
- Up to 25% of patients in one series
Poor prognosis; presents with early & widespread stage IV disease
- Typically with hepatic metastases
Rarely secondarily arise in pre-existent splenic cyst
Morphology:
- Diffuse infiltration or ill-defined hemorrhagic mass(es)
Attenuation:
- Mixed with high attenuation components (hemorrhage, hemosiderin, soft tissue)
Enhancement:
- Variable with central & peripheral nodular hyper-enhancement (hypervascularity)
Calcifications: infrequent
Ancillary features: metastatic disease

Hemangiosarcoma - Epithelioid

Hemangiosarcoma - Pleiomorphic

Hemangiosarcoma - Histiocytic

"On imaging, splenic candidiasis presents as multiple focal lesions that are small (< 1 cm) and rounded. They are hypoechoic on US, and minimally enhanced on CT and MRI. They are best visualized as hyper-intense on T2-weighted sequences and on diffusion sequences. Splenic candidiasis is most often associated with hepatic candidiasis, with hepatic lesions that show the same characteristics as the splenic lesions on imaging. MRI is suggestive when it reveals the ‘‘bull’s eye’’ sign (echogenic center sur- rounded by a hypo-echoic zone).”
Diagnosis and treatment of focal splenic lesions
B. Malgras, H. Najah, A. Dohan et al.,
Journal of Visceral Surgery, https://doi.org/10.1016/j.jviscsurg.2021.11.010

“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

“In patients with known malignancy or with constitutional symptoms and/or pain localized to the left upper quadrant or epigastrium, although most masses will also be benign, such patients require further assessment.”
The Incidental Splenic Mass at CT: Does It Need Further Work-up? An Observational Study
Siewert B et al.
Radiology 2018; 287:156–166

Summary: CT of the Spleen

Lesion detection
Lesion definition
Lesion etiology determination
Minimize un-necessary intervention