Imaging Features of Sclerosing Angiomatoid Nodular Transformation in Spleen

The purpose of this study was to evaluate the features of sclerosing angiomatoid nodular transformation (SANT) in spleen on the imaging of computed tomography (CT) and magnetic resonance (MR).

From July 2006 to April 2017, 12 patients with SANT confirmed by pathology were evaluated in a retrospective study. Eight patients were with CT imaging only, 2 patients were with MR imaging only, and 2 patients were with both CT and MR. Three professional senior radiologists analyzed the imaging features on CT and MR. The main characteristic analysis included size, margin, density, signal intensity, and enhancement pattern. The significant enhancement was defined as the degree of enhancement of lesion that is higher than the surrounding spleen parenchyma, and the mild enhancement was defined as the degree of enhancement of lesion that is lower than the surrounding spleen parenchyma.

All the 12 patients (5 men, 7 women; mean age, 45.8 years; age range, 21-62 years) presented as single lesion without special clinical symptoms. The range of lesions on diameter was from 25 to 80 mm. On CT images, 9 (90%) of 10 presented as hypodense in comparison with the parenchyma of spleen, 1 (10%) of 10 presented as isodense, and calcification was observed in 4 (40%) of 10 cases. On MR images, 4 (100%) of 4 manifested heterogeneous hypointensity on in-phase sequence and 3 (75%) of 4 performed as isointensity on out-of-phase sequence of T1-weighted. On the sequences of T2-weighted and diffusion-weighted image, 4 (100%) of 4 showed hypointensity. On CT and MR enhancement images, the number of significant enhancement and mild enhancement was 2 and 10, respectively. Seven (58%) of 12 showed progressive enhancement with the pattern of "spoke-wheel."

Imaging features on CT and MR have a high diagnostic value for SANT, especially when CT combined with MR examination.