Sclerosing angiomatoid nodular transformation of the spleen

Abstract

A 45-year-old man with no known underlying disease presented with left upper quadrant pain for 2 weeks. There were no other symptoms such as fever or night sweats. X-ray of KUB found calcified lesions over left upper abdomen (Figure 1A). Ultrasound of abdomen showed multiple mixed-echoic tumors of the spleen. Further abdominal computed tomography showed multiple contrast-enhanced spleen masses. A “spoke wheel” pattern and peripheral enhancement around the spleen lesion were seen during the arterial phase on further magnetic resonance imaging (MRI) (Figure 1B).

An endoscopy of the upper and lower gastrointestinal tract revealed no malignancy. The role of surgery is to confirm the correct diagnosis and to exclude the suspicion of malignancy. A surgical consultation was requested to evaluate the incidentally found splenic mass. Laparoscopic splenectomy was performed without complication afterward. The pathological report of splenectomy confirmed the spleen lesion as sclerosing angiomatoid nodular transformation (SANT) (Figure 2).

The patient remained asymptomatic with no evidence of recurrence over the two-year follow-up period.

SANT is a rare benign non-neoplastic vascular splenic lesion that was first reported by Martel et al.¹ It usually occurs in middle-aged adults as an incidental finding on imaging. The differential diagnosis of SANT includes both benign tumors and malignant vascular lesions such as splenic hamartomas, hemangiomas, littoral cell angiomas, angiosarcoma, lymphoma, and myeloma.²

Classical feature of SANT on a postcontrast CT is described as a hypovascular splenic mass with enhancing rim and peripheral enhancing radiating lines towards center of the mass, known as the “spoke-wheel” pattern.³

Preoperatively diagnosing SANT based on fine needle aspiration cytology was debatable.⁴

Albeit this lesion has characteristic radiological findings on both CT and MRI scans, it may pose a difficulty in distinguishing this rare benign entity from other lesions of the spleen both clinically and radiologically. The conventional treatment for SANT involves splenectomy, which is both therapeutic and diagnostic.

The authors declare no conflicts of interest.

Written informed consent was obtained from the patient.