A rare case of sclerosing angiomatoid nodular transformation of the spleen disguised as splenic metastasis of sigmoid colon cancer

초록

Splenic metastases from solid tumors are considered an exceptional clinical diagnosis and usually found on a part of widespread metastatic disease. Sclerosing angiomatoid nodular transformation of the spleen (SANT) is a recently recognized, rare, non-neoplastic vascular splenic lesion of uncertain etiology and is often disguised as a potentially malignant entity in the diagnostic process.The SANT was first reported in the literature in 2004 by Martel et al. A 62-year-old female with appropriately managed and monitored AJCC stage II sigmoid colon cancer eleven years ago, was newly found to have a splenic incidentaloma on abdominal and pelvic CT scan heterogeneous enhancement, well-circumscribed lesion measuring 5.4 x 4.5 cm in the inferior pole of spleen (Fig. 1 ). The radiological differential diagnosis was focused on suspected metastatic mass or primary splenic angiosarcoma. Based on the above-mentioned clinical and CT findings, the patient underwent a laparoscopic splenectomy under the diagnosis of metastatic splenic tumor.This tumor was finally proved by pathological examination to be a SANT of spleen. Macroscopically, the sp leen, measuring 13.0 x 6.0 x 5.0 cm, was enlarged by the mass, which measu『ed 6.0 x 5.0 cm. The cut surface of the splenic mass was firm, gritty consistency with variegated appearance. Microscopically, the mass was composed of multiple vascular structures separated by fibrous connective tissue and immunohistochemical analysis revealed positive staining for CD3 l, CD34, ERG, and lgG4 and negative for CDS consistent with diagnosis of SANT of spleen. The postoperative course was uneventful and the patient was discharged without any complications on the fourteenth postoperative day. Most of the patients with pathologically confirmed SANT of the spleen were asymptomatic preoperatively and thus were usually found incidentally as a splenic incidentaloma prior to surgery.