Gastrointestinal: Colorectal metastases from gastric poorly differentiated carcinoma presenting as a diminutive polyp

Abstract

A 62-year-old woman with a history of hypertension and hyperlipidemia was referred to our hospital for abdominal discomfort and nausea. Laboratory test results were unremarkable. Colonoscopy revealed multiple diminutive lesions in transverse and sigmoid colon. These lesions were whitish and slightly elevated diminutive lesions with central redness (Fig. 1a,b). Magnifying narrowband imaging (M-NBI) showed irregularly distributed microvessels with varying caliber, which was particularly dense in the center, and indistinct surface pattern (Fig. 1c).

Histopathological examination of the snare-resected lesion revealed poorly differentiated adenocarcinoma with signet-ring cell carcinoma in the mucosal layer (Fig. 1d). Esophagogastroduodenoscopy indicated giant and stiff folds in whole of stomach, biopsy of which showed poorly differentiated adenocarcinoma with signet-ring cell carcinoma (Fig. 2). Immunohistochemical staining revealed that both the gastrtic and colon lesions were positive for CK7 but negative for CK 20. Therefore, the patient was diagnosed as gastric carcinoma with multiple colon metastases. No other distant metastasis was detected on computed tomography. It was unresectable because of the colon metastases, and the patient underwent chemotherapy but died 3 months later.

Colonic metastases from gastric cancer is rare but sometimes presents as diminutive lesions.^1-3 The present case showed some characteristic findings that may be useful in differentiation from other colorectal polyps. Furthermore, similar reports of this type of metastases indicated signet-ring cell carcinoma histology.^1-3 In the case of diminutive colorectal lesions with characteristic findings shown in current case, additional examination should be scheduled in consideration of metastasis from gastric signet-ring cell carcinoma.