Splenoses and Other Ectopic and Heterotopic Splenic Tissue: The Use of Long-Lasting Enhancement in Contrast-Enhanced Ultrasound to Avoid Unnecessary Intervention.

This narrative review describes variants of heterotopic and ectopic spleen tissue, focusing on its appearance under contrast-enhanced ultrasound (CEUS) with SonoVue (SonoVue®; Bracco, Milano, Italy). Typical feature of splenic tissue with SonoVue is its long-lasting enhancement. The diagnosis of these splenic variants, in the vast majority of cases, has primarily been performed with CT, MRI, spleen-specific scintigraphy, or image-guided biopsy. In this review, we analyze published cases and also include our own case examples where CEUS has been used, and describe the enhancement characteristics of splenosis and atypical (intrapancreatic) accessory spleens. CEUS can provide valuable diagnostic information in patients with suspected ectopic splenic tissue, particularly when interpreted together with clinical history and complementary imaging modalities. Ultimately, ectopic splenic tissue should be considered, especially after splenectomy or splenic trauma, in cases of well-defined, hypervascularized lesions where CEUS may help avoid unnecessary invasive procedures in selected cases.