Case report: Coexistence of rectal signet ring cell carcinoma with neuroendocrine components

Signet ring cell carcinoma is a rare histological type among the various forms of colorectal cancers. Even rare is when it coexisted with neuroendocrine components in one tumor. To date, there is little literature reported case of colorectal cancer diagnosed as signet ring cell carcinoma with neuroendocrine components.

This report presents a unique case manifested as obstructed defecation for more than one month but with negative endoscopic biopsies. Laparoscopic abdominoperineal resection was performed. Based on the postoperative pathology, the patient was finally diagnosed as signet ring cell carcinoma with neuroendocrine differentiation among poorly differentiated adenocarcinoma.

We highlight the rare coexistence of signet ring cell carcinoma and neuroendocrine differentiation in this case. We also emphasize the special characteristic of intramural growth without penetrating the mucosa in signet ring cell carcinoma, further to pose the pitfalls and share lessons during our diagnosis and treatment process.