CASE REPORT

An 81 year-old anticoagulated male patient, with a medical history of atrial fibrillation and valvular cardiomyopathy, performed a total colonoscopy due to intermittent hematochezia, which revealed in the distal rectum a well-defined and regular protruded sessile lesion with 16 mm (T0 Is) (Figure 1). Biopsies showed a well differentiated neuroendocrine tumor (NET).

Figure 1: Protruded sessile lesion (T0 Is) with 16 mm, in the distal rectum.

Endoscopic ultrasound examination (EUS) identified a hypoechoic lesion with clear margins arising from the second layer, without lymph node or muscular layer involvement (Figure 2).

Figure 2: Hypoechoic lesion arising from the second layer.

Abdomino-pelvic computerized tomography (CT) and Octreoscan® showed no distant metastasis. Multidisciplinary evaluation was carried out and excision of the tumor by endoscopic submucosal dissection (ESD) was planned. The procedure was performed with no complications reported (Figure 3: A to F).

Figure 3: A to F – Endoscopic excision of a rectal neuroendocrine tumor by endoscopic submucosal dissection (circumferential mucosal cutting and submucosal dissection performed with the Dual-Knife, Olympus®).

Pathological analysis confirmed the diagnosis of a totally resected well differentiated neuroendocrine tumor (G1) with a low mitotic index (Ki67 < 2%) and no lymphovascular invasion. No distant metastasis were identified during the follow up period (2 years).

Commentary

The incidence of rectal neuroendocrine tumors has been rising largely due to an increased number of screening colonoscopies, allowing for identification of smaller lesions amenable to endoscopic treatment¹. Indeed, endoscopic therapy of neuroendocrine tumours may be considered in lesions below 2 cm, without muscularis invasion according to the European Neuroendocrine Tumor Society 2012 consensus guidelines². However, the incidence of metastasis of rectal carcinoid tumors increases when they are larger than 10 mm, have muscular invasion, poorly differentiated histology, and lymphatic or vascular involvement. Therefore, EUS has shown to be useful during preoperative evolution for measuring the size and depth of rectal carcinoid tumors. Moreover, EUS is not considered technically difficult in this setting as the endoscope is easily maneuvered in the rectum³.

References

1. Scherübl H., Rectal carcinoids are on the rise: early detection by screening endoscopy. Endoscopy. 2009;41(2):162-5.

2. Caplin M, Sundin A, Nillson O, et al. ENETS Consensus Guidelines for the management of patients with digestive neuroendocrine neoplasms: colorectal neuroendocrine neoplasms. Neuroendocrinology. 2012;95(2):88-97.

3. Ishii N., Horik N, Itoh T, et al. Endoscopic submucosal dissection and preoperative assessment with endoscopic ultrasonography for the treatment of rectal carcinoid tumors. Surg Endosc. 2010;24(6): 1413-9.

 

Authors

José Rodrigues¹, Liliana Carvalho¹, Susana Marques¹, Pedro Barreiro¹, Pedro-Pinto-Marques², Cristina Chagas¹

1. Serviço de Gastrenterologia, Hospital de Egas Moniz, Lisboa

2. Serviço de Gastrenterologia, Hospital Garcia de Orta, Almada