Sonography of splenic tumors: The almost forgotten organ in abdominal US examination

Abstract

Although examination of the spleen is routinely included in the general abdominal gray-scale ultrasound (US) study, it was considered of limited use in the past and was performed almost only to distinguish between cystic and solid lesions. In the last two decades due to accumulated experience and the introduction of second-generation contrast agents, this technique has been re-evaluated as contrast-enhanced US (CEUS) allows detection and characterization of most focal lesions of the spleen with a high sensitivity and a good specificity. US can provide a correct diagnosis in simple cysts, whereas CEUS is useful when cystic lymphangioma is suspected. US presents a low specificity and relatively low sensitivity in splenic infarctions, while CEUS can achieve a high specificity (up to 100 %). There is a wide spectrum of benign and malignant neoplasms of the spleen. Lymphomas and vascular tumors comprise the most common splenic neoplasms. Splenic hemangiomas and angiosarcomas are the most common mesenchymal tumors in which US and CEUS may show characteristic imaging findings and permit precise diagnosis. US-guided fine needle aspiration and/or biopsy of focal splenic lesions are being increasingly performed to obtain tissue for histopathological characterization. Accurate diagnosis of focal splenic lesions allows institution of optimal patient management. In the study of splenic lesions, the most important problem is to differentiate between angioma, hamartoma, lymphoma, and metastasis. CEUS presents a high specificity in the differentiation of benign and malignant splenic lesions, as hypoenhancement in the parenchymal phase is suggestive of malignancy in 87 % of cases. US, as compared to CT and MRI, has certain advantages, including its ubiquitous availability, lack of ionizing radiation, and low cost, and with additional application of CEUS, can be widely indicated in the study of focal splenic lesions.