Small cell neuroendocrine carcinoma of rectum with associated paraneoplastic syndrome: a case report.

Neuroendocrine carcinomas of the colon and rectum comprise fewer than 1% of all colorectal cancers. These aggressive tumors generally have a poor prognosis compared to that associated with colorectal adenocarcinoma. We describe herein the case of a 68-year-old female presenting with a bleeding rectal mass involving the anal canal, which case was associated with hyponatremia due to inappropriate serum levels of antidiuretic hormone. The histopathological examination was consistent with a small-cell neuroendocrine tumor. She was treated with combination chemotherapy and radiation therapy. The Syndrome of Inappropriate Antidiuretic Hormone (SIADH) was managed with vasopressin antagonists. After the completion of therapy, endoscopic ultrasound revealed evidence of residual disease, for which she underwent an abdominoperineal resection (APR). The patient died 4 months later of disease progression. To our knowledge, this is the first report of a small-cell neuroendocrine tumor involving the rectum and anal canal that presented with the paraneoplastic syndrome, SIADH.

Intestinal endometriosis as a cause of rectal bleeding: a case report.

Endometriosis is the presence of endometrial glands and stroma outside the uterine cavity and musculature. The estimated prevalence of endometriosis in Puerto Rico is 4.0%. The exact prevalence of extra-pelvic endometriosis is unknown. It has been reported that affects the intestinal tract in 3-37% of all patients with pelvic endometriosis, with the sigmoid colon and rectum being the most commonly involved areas. It can mimic colorectal cancer by producing an invasive abdominal mass. We present the case of a 40 y/o female patient with rectal bleeding that presented a mass on a colonoscopy highly suggestive of cancer. After all the studies and an exploratory laparotomy, the diagnosis was intestinal endometriosis. Because of lack of published data about intestinal endometriosis in Puerto Rico, it is very important to show this condition in order to properly assess young women with rectal bleeding in light of a clinical suspicion of endometriosis.