Hot spleen: hypervascular lesions of the spleen

The differential diagnosis of splenic masses is broad and often hinges on the enhancement characteristics of the lesions. Most radiologists are familiar with the differential diagnosis of hypovascular lesions such as fungal infections, sarcoidosis/granulomatous disease, infarctions, and cysts. However, to our knowledge, there is no review article that presents the specific multimodality imaging features of vascular splenic lesions as a group. Vascular splenic lesions may be considered those that enhance more or similarly to the background splenic parenchyma. In this review, we illustrate the spectrum of imaging features of both benign and malignant vascular splenic lesions. The benign lesions include hemangiomas, hamartomas, and sclerosing angiomatoid nodular transformation of the spleen. The malignant lesions are divided into primary and metastatic lesions, ranging from lymphoma, angiosarcoma to pleomorphic sarcoma. While lymphoma and metastases may commonly present as hypoenhancing lesions relative to the background parenchyma, we are addressing them here as their appearance can be varied and hence deserve consideration. Littoral Cell angiomas are discussed separately, as they were originally considered benign, but recent studies have shown that they can have malignant potential.