Rare Tumors of the Colorectal Region

Rare tumors of the colon and rectum account for less than 5% of all colorectal tumors. The most common of these rare tumors include anorectal melanoma, rectal neuroendocrine tumors, rectal gastrointestinal stromal tumors (GISTs), and retrorectal tumors. Their prognosis is varied and depends on underling pathology. Surgery plays an important role in many of these tumors. Molecularly targeted therapy and immunotherapy have expanding roles in GIST and anal melanoma, respectively. Adjuvant chemotherapy or radiation therapy may be employed in specific circumstances of unresectable or metastatic disease or for symptom control. This review contains 4 figures, 6 tables and 60 references. Key words: anal canal, antineoplastic agents, anus neoplasms, chordoma, gastrointestinal stromal tumors, melanoma, neuroendocrine tumors, operative, radiotherapy, rectal neoplasms, surgical procedures