Incidental sclerosing angiomatoid nodular transformation of the spleen

Sclerosing angiomatoid nodular transformation (SANT) is a rare, often asymptomatic, tumour of the spleen, typically discovered incidentally during imaging for unrelated reasons. In this case, a SANT was discovered in the spleen of an otherwise healthy man in his 40s undergoing a CT for an unrelated issue. The mass was evaluated by MRI, F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT and sulfur colloid scintigraphy. The mass demonstrated gradual enhancement with central and radiating non-enhancing components in keeping with the previously described spoke-wheel enhancement pattern. The central components enhanced at the same rate as peripheral components while the non-enhancing components never filled in. The mass was slightly hypermetabolic relative to the liver on FDG PET/CT and demonstrated a sulfur colloid scintigraphic defect. It was removed en bloc by total splenectomy. Pathological evaluation revealed bosselated contours with nodules of vascular elements surrounded by an outer concentric rim of hyalinised fibrosis typical of SANT.