Minute liver metastases from a rectal carcinoid: A case report and review

Neuroendocrine neoplasms of rectum: A management update

The estimated annual incidence of R-NENs is 1.04 per 100,000 persons although the real incidence may be underestimated, as not all R-NEN are systematically reported in registers. Also the prevalence has increased substantially, reflecting the rising incidence and indolent nature of R-NENs, showing the highest prevalence increase among all site of origin of NENs. The size of the tumor reveals the behavior of R-NENs where the risk for metastatic spread increases for lesions > 10 mm. Applying the WHO 2010 grading system to whole NENs originating in the gastroenteropancreatic system, R-NENs are classified as Well-Differentiated Neuroendocrine Tumors (WD-NET), which contain NET G1 and NET G2, and Poorly-Differentiated Carcinomas (PD-NEC) enclosing only G3 neoplasms for which the term carcinoma is applied. The treatment is endoscopic resection in most cases: conventional polypectomy or endoscopic mucosal resection (EMR) for smaller lesions or endoscopic submucosal resection with a ligation device (ESMR-L), cap-assisted EMR (EMR-C) and endoscopic submucosal dissection (ESD). However it is important to know when the endoscopic treatment is not enough, and surgical treatment is indicated, or when the latter could be unnecessary. For PD-NECs, it has recently been demonstrated that chemoradiotherapy is associated with a similar long-term survival to that obtained with surgery. As well, new targeted-agents chemotherapy may be indicated for metastatic WD-NETs.

Management of sub-5 mm rectal carcinoids with lymph node metastases

Minute (<5 mm) and small (5–10 mm) rectal carcinoids discovered during colonoscopy are generally considered to be non-aggressive, and the management and surveillance of patients with this entity are usually limited. We present the case of a 61-year-old Chinese female with multiple sub-5 mm carcinoid tumours in the rectum without any computed tomography (CT) evidence of lymph node or distant metastases. She underwent an ultra-low anterior resection for a sessile rectal polyp with the histological appearance of a moderately differentiated adenocarcinoma. Seven foci of minute carcinoids in the rectum and perirectal lymph node metastastic spread from the carcinoid tumours were also discovered on histopathology. There were no lymph node metastases originating from adenocarcinoma. This case report and review of the literature suggests that minute rectal carcinoids are at risk of metastasizing and that these patients should be investigated for lymph node and distant metastatic spread with CT and somatostatin receptor scintigraphy or its equivalent, as this would influence prognosis and surgical management of these patients. Findings relating to lymphovascular invasion, perineural invasion, high Ki-67, mitotic rate, depth of tumour invasion, central ulceration, multifocal tumours and size are useful in predicting metastases and may be used in scoring tools. Size alone is not a good predictor of metastastic spread.