rectal carcinoid tumor
Most rectal carcinoids are asymptomatic and are discovered incidentally during proctoscopy, sigmoidoscopy, or digital rectal examination.
Patients who do have symptoms typically present with rectal pain, bleeding, or constipation.
Though these neoplasms represent only 1.3% of all rectal tumors, the true incidence of rectal carcinoids appears to be on the rise because of recent advances in endoscopic technology.
Like carcinoids of the small bowel and colon, these tumors are thought to arise from the epithelial endocrine cells; however, unlike these neoplasms, rectal carcinoids contain glucagon and glicentin-related peptides, rather than serotonin.
Development of typical carcinoid syndrome is rare. Interestingly, the size of rectal carcinoids correlates closely with the aggressiveness of the tumor and metastatic potential.
Recent series have shown that tumors <1 cm rarely metastasize, while lymph node and liver metastases are seen in up to 70% of cases in which the primary tumor is >2 cm.
Overall 5-year survival rates from the SEER database for localized, regional, or distant disease spread beyond the rectum and rectosigmoid junction over a 10-year period were 90%, 49%, and 26%, respectively.
See also
carcinoid tumors
- digestive carcinoid tumors