Primary Choriocarcinoma of the Rectum in a Man Case Report and Literature Review

A case of pure extragonadal choriocarcinoma in the rectum of an 84-year-old man is described. The patient complained of rectal bleeding and lower abdominal pain. The trophoblastic origin of the tumor was documented by immunoperoxidase staining for human chorionic gonadotropin. The DNA histogram showed a diploid pattern. The patient died 106 days after diagnosis. Only eight cases of choriocarcinoma of the large intestine have been reported, three of which were located in the rectum. The age of patients affected range widely, from 28 to 84 years with a mean of 54 years: 79 for males and 46 for females. Women are affected three times as often as men. The pathologic study showed adenocarcinoma with germ cell elements in seven cases: six choriocarcinoma and one mixed (choriocarcinoma and endodermal sinus tumor). Germ cell differentiation may be difficult to identify in small biopsy samples, which may not be representative of the tumor as a whole. The prognosis of patients with choriocarcinoma of the large bowel is very poor; survival is less than 5 months. Although choriocarcinoma in the rectum is very rare, it should be included in the differential diagnosis of rectal neoplasms.