In signet ring adenocarcinoma, skin cells from the lining of internal organs lose their structure and become unsuitable for their intended purpose. These cells reproduce quickly and bond together to form cancerous growths. This form of cancer typically affects the organs of the digestive system, but signet ring cells, theoretically, can occur in any organ that is lined with epithelium. Adenocarcinoma of this type is rare but very aggressive.
The peculiar physical appearance of the individual cancer cells give signet ring adenocarcinoma its name. Normally, the portion of the cell that contains the deoxyribonucleic acid (DNA) needed for reproduction is located in the center of the cell. In signet ring cells, this structure, called the nucleus, is off center and suspended in mucus. The resulting structure resembles the emblem-baring rings traditionally used by royalty.
The presentation of signet ring adenocarcinoma is identical to more common cancers of the same organ. In stomach cancer, these symptoms may include gut pain, upset stomach, and bloody stools. Although exceedingly rare, this condition can affect the lungs. In these cases, persistent cough, chest pain, and bloody mucus are often reported.
Diagnosis of signet ring adenocarcinoma is generally accomplished by a combination of blood tests and diagnostic imaging. Abnormal blood cell counts can indicate the presence of cancer, and patient symptoms can provide clues to its location, but finding the exact position of an abnormal growth requires ultrasound, X-ray, or magnetic resonance imaging (MRI) procedures. If a tumor is found, a surgeon usually takes a small sample of the growth in a procedure called a biopsy. Visual confirmation of signet ring cells occurs by examining the tissue under a microscope.
Depending on the area affected, the surgical removal of a cancerous growth may be necessary. Although radiation treatment may be used briefly before surgery, postoperative radiation therapy is not usually recommended. Due to the aggressive nature of signet ring adenocarcinoma, chemotherapy is almost always prescribed.
Frequently, signet ring cancers of the lower digestive tract are treated with a special type of chemotherapy called hyperthermic intraperitoneal chemotherapy (HIPEC). After any tumors in the stomach are removed, chemotherapeutic drugs are heated to slightly above normal body temperature and cycled through the abdominal cavity. In many cases, the localized application of the drugs can reduce the systematic side effects of traditional chemotherapy.
The prognosis for patients suffering from signet ring adenocarcinoma is generally poor. Historically, the disease is extremely aggressive and has frequently spread to other areas of the body before a diagnosis is made. In addition, the cancer is not typically responsive to chemotherapy.