Signet ring cell carcinoma (SRCC) is a rare form of highly malignant adenocarcinoma[1] that produces mucin.

[5] SRCC tumors grow in characteristic sheets, which makes diagnosis using standard imaging techniques, like CT and PET scans, less effective.

[citation needed] Highly differentiated adenocarcinomas form SRCCs via a loss of adherens and tight junctions that typically separate MUC4, a mucin protein, and ErbB2, an oncogenic receptor.

[12] The mechanism of this malignant cancer is still unclear; however, it has been found that a colon carcinoma cell known as HCC2998 causes an increase in differentiated tumor production.

[15] SRCCs are named due to their resemblance to signet rings, which result from the formation of large vacuoles full of mucin that displaces the nucleus to the cell's periphery.

[16] Stomach cancers with both adenocarcinoma and some SRC (known as mixed-SRCC) exhibit more aggressive behavior than purely SRCC or non-SRCC histologies.

[19] In the future, case studies indicate that bone marrow metastases will likely play a larger role in the diagnosis and management of signet ring cell gastric cancer.

[24] Primary signet-ring cell carcinoma of the urinary bladder is extremely rare and patient survival is very poor and occurs mainly in men ages 38 to 83.

However, one such patient treated with a radical cystectomy followed by combined S-1 and Cisplatin adjuvant chemotherapy did demonstrate promising long-term survival of 90 months.

[25] Primary signet ring cell carcinoma of the colon and rectum (PSRCCR) is rare, with a reported incidence of less than 1 percent.