Imaging description

Littoral cell angioma of the spleen is a rare vascular tumor first described in 1991 [1] that is thought to arise from the littoral cells which normally line the splenic sinuses of the red pulp. These lining cells have dual endothelial/vascular and macrophage/histiocytic potential, and this duality is a distinctive morphologic and immunophenotypic feature of littoral cell angioma. Littoral cell angioma typically occurs as multiple, similarly sized, well-circumscribed but non-encapsulated nodules of spongelike vascular spaces within a variably enlarged spleen [2]. At ultrasound, littoral cell angioma may manifest as diffuse heterogeneity or multiple nodules that are hypoechoic, isoechoic, or hyperechoic [3–6]. At non-enhanced or enhanced CT, the tumor is seen as multiple hypodense nodules. This finding is non-specific, but homogeneous enhancement of the lesions such that the nodules become isoattenuating and virtually invisible on delayed contrast-enhanced CT images appears to be a relatively distinctive diagnostic feature (Figure 30.1) [2,6, 7]. At MRI, the nodules of littoral cell angioma are typically of low T1 and low T2 signal intensity, probably due to hemosiderin deposition secondary to phagocytosis of red blood cells [2].

Importance

The finding of multiple nodules in the spleen generally suggests serious pathology, such as metastases, lymphoma, abscesses, or granulomatous disease such as sarcoidosis or tuberculosis.