Imaging description

Splenic hemangiomas are non-encapsulated benign proliferations of vascular channels that range from capillary to cavernous in size [1]. Smaller hemangiomas are usually solid while larger hemangiomas may be partially cystic or calcified, presumably secondary to thrombosis and infarction (Figures 29.1 and 29.2). At ultrasound, splenic hemangiomas typically appear as well-defined solid echogenic or complex partially cystic masses. At CT, hemangiomas appear as hypodense well-circumscribed masses with marked homogeneous enhancement of the solid components. Delayed enhancement has been described for splenic hemangiomas at CT, but they reportedly have a mottled heterogeneous appearance in contrast to the typical centripetal enhancement of hepatic hemangiomas [2]. At MRI, smaller splenic hemangiomas resemble hepatic hemangiomas with T2 hyperintensity and delayed centripetal enhancement [3], but larger lesions are more variable [1]. There is some discrepancy between the reported CT versus MRI delayed enhancement patterns [2, 3], but this may partially reflect the fact that routine MRI includes more delayed acquisition times than routine CT. While splenic hemangiomas may demonstrate centripetal enhancement (Figures 29.3 and 29.4), they lack the typical nodular globular pattern of peripheral enhancement seen in hepatic hemangiomas [1, 4]. This may reflect differences in vascular supply (dual blood supply to the liver versus single blood supply to the spleen), but this is speculative.