Sclerosing angiomatoid nodular transformation of the spleen: clinical and radiologic characteristics.

Abstract

Background Sclerosing angiomatoid nodular transformation (SANT) is a rare benign primary vascular lesion of the spleen. Although there have been many reports about the pathology of SANTs of the spleen, there have been no comprehensive descriptions of the imaging findings of SANTs of the spleen. Purpose To determine the clinical characteristics and imaging findings of SANTs of the spleen. Material and Methods We retrospectively evaluated seven patients with pathologically confirmed SANT, who underwent CT (n = 7), MRI (n = 4), ultrasonography (n = 4), and PET/CT (n = 3). Follow-up CT examinations were obtained in five patients. Clinical characteristics such as symptoms and concurrent disease were assessed. CT and MRI findings were evaluated by two radiologists, including the number, border, signal intensity, enhancement pattern, hemorrhage, and cystic change or necrosis. The longest diameter of each tumor was measured on CT. Echogenicity on ultrasonography and standardized uptake value on PET/CT were also evaluated. Results No specific symptom was associated with SANT. Two patients had a history of malignancy, one with cervical cancer and the other with early gastric cancer. Tumor growth was observed in four of five patients. On CT, all seven SANTs appeared as single, well-demarcated masses. CT showed a heterogeneous enhancement in seven patients. MRI showed centripetal progressive enhancement and absence of cystic change or necrosis in four patients, with three of these patients showing evidence of old hemorrhage. Ultrasonography showed heterogeneous hypoechoic mass in four patients. PET/CT showed increased standardized uptake value, ranging from 2.0 to 2.8, in three patients. Conclusion SANT of the spleen is a single, well-demarcated solid mass without cystic change or necrosis. Increased FDG activity and tumor growth on follow-up imaging are common.