Sarcoid reaction in the spleen after sigmoid colon cancer resection: a case report

BACKGROUND: A sarcoid reaction is a phenomenon characterized by histologically proven granulomatous lesions without evidence of sarcoidosis. This pathology is a benign tumor itself, but several reports have described sarcoid reactions accompanying malignant tumors. Sarcoid reactions occur in various cancers, such as skin, lung, ovary, stomach, and breast cancers. However, only a few published reports have described sarcoid reactions in patients with colorectal cancer. CASE PRESENTATION: A 76-year-old woman underwent laparoscopic sigmoidectomy for sigmoid colon cancer. The postoperative follow-up computed tomography and 18-fluorodeoxyglucose positron emission tomography–computed tomography findings were suspicious for splenic metastasis of the sigmoid colon cancer. The patient then underwent laparoscopic splenectomy. Histopathological examination of the resected lymph nodes and spleen showed a non-caseating epithelioid cell granuloma. The patient was diagnosed with a sarcoid reaction. CONCLUSIONS: To our knowledge, this is the first report of a sarcoid reaction in the spleen and regional lymph nodes after colon cancer resection. The effect of a sarcoid reaction on the prognosis in patients with colorectal cancer has not been fully determined because of the small number of such cases. Further analyses involving a larger number of cases are necessary to evaluate the relationship between sarcoid reactions and prognosis in patients with colorectal cancer. We herein present an extremely rare case of a sarcoid reaction in the spleen and regional lymph nodes.