Littoral cell angioma of the spleen

Littoral cell angioma of the spleen is a rare, benign primary vascular tumor of the spleen.

Epidemiology

Littoral cell angiomas may occur at any age and have no gender predilection.

Associations

Littoral cell angiomas have been diagnosed in association with various malignancies outside the spleen ^10,12. The condition has also been linked to Crohn disease ^13,14.

Clinical presentation

The lesion is often detected incidentally in asymptomatic patients. Symptomatic patients may present with abdominal pain, splenomegaly on physical examination, and/or laboratory evidence of hypersplenism including anemia and thrombocytopenia.

Pathology

Littoral cell tumors arise from the littoral cells lining the sinusoids of splenic red pulp. Littoral cell angiomas are the benign type, as opposed to the less common, low-grade malignant littoral cell hemangioendothelioma and the rare and aggressive littoral cell angiosarcoma ⁹.

Macroscopic appearance

The spleen is enlarged with multiple nodules, the color of which varies by age of blood products ⁷.

Microscopic appearance

Histopathology demonstrates a proliferation of anastomosing vascular channels congested with blood and lined with tall endothelial cells that show hemophagocytosis ^7,8.

Immunophenotype

The tumor cells express both vascular endothelial markers (such as CD31 and factor VIII) and histiocytic markers (such as CD68) ^7,8.

Radiographic features

Imaging usually demonstrates splenomegaly and multiple mass lesions.

CT

There are multiple nodules or masses which are hypoattenuating compared to normal spleen ^2-8. They demonstrate progressive homogeneous contrast enhancement, later than normal splenic parenchyma ².

MRI

The masses are often low in T1 and T2 signal intensity due to hemosiderin ⁷.

Treatment and prognosis

As many patients are symptomatic and imaging findings are non-specific, splenectomy is usually performed for definitive histological diagnosis and treatment. Littoral cell angiomas are considered benign.

Differential diagnosis

The imaging differential includes

• metastases
• lymphoma
• sarcoidosis
• other primary splenic vascular tumors, such as hemangioma, hamartoma, hemangioendothelioma, angiosarcoma