Colorectal Signet Ring Cell Carcinoma: Incidence and Epidemiological Distribution at a Tertiary Care Center from 2002 to 2012

Background: Primary colorectal signet ring cell carcinoma (SRCC) is a rare finding with an incidence of 0.9% to 4%. This entity is characterized by an aggressive tumor biological behavior and is associated with a worse outcome compared to mucinous or adenocarcinoma. SRCC are defined as carcinoma cells with ≥50% intracellular mucin of the tumor mass displacing the nuclei to the side. Tumor cells comprising ≥50% extracellular mucin of the tumor mass are classified as mucinous carcinomas. The aim of this study was to analyze the incidence and epidemiological distribution of SRCC in colorectal cancer patients at our tertiary care unit.

Methods: In our prospective designed institutional database 759 consecutive patients with primary colorectal cancer from January 2002 to October 2012 were analyzed and investigated for clinicopathological and epidemiological parameters of SRCC.

Results: Of the 759 patients 649 (85.7%) were adenocarcinoma, 101 (13.3%) mucinous and 9 (0.9%) SRCC. Nine SRCC patients (female 56%) with a median age of 66 (range 38–76) were analyzed. Tumor localization: right colon (n=5), left colon (n=2) and rectum (n=2). All SRCC presented at later stage (UICC III: n=5, UICC IV: n=4). 45% had metastasis at the time of diagnosis. Three died within one year after diagnosis.

Conclusion: Colorectal SRCC are characterized by advanced stage at diagnosis. Predilection site in our cohort was the right colon. Because of the aggressive biological behavior of SRCC a more radical surgical approach, modified chemotherapy trials and a closer follow up are necessary.