Endoscopic Resection of Early Rectal Carcinoid Tumor

In a paper recently published in Endoscopy, Nagai et al. [1] report on eight endoscopic resections of early rectal carcinoid tumors using the cap aspiration method. It is reassuring that all of the tumors were resected completely, although recurrence rates are not given. The authors describe the cap aspiration method as being an extremely safe procedure, since no immediate or late complications such as perforations occurred. They are not aware of any cases of perforation having been reported in the literature.

In our institution, we have resected two early rectal carcinoid tumors using the cap aspiration method. Both tumors (4 mm and 5 mm in size) were resected completely. There were no procedure-related complications in the first patient. A perforation occurred in the other patient, a 67-year-old woman who was in good general condition.

The intervention itself was uneventful. After 20 ml isotonic sodium chloride had been injected, a ligation device (Mandel and Rupp, Erkrath, Germany) was used. The aspirated tumor was easily snared (Figure [1]). The histological work-up showed a highly differentiated neuroendocrine tumor, with proliferation activity (Ki-67) below 1 %. There was no serotonin production and no immunohistochemical interaction with a somatostatin receptor antibody. The tumor was located just below the muscularis mucosae; complete resection was documented by the fact that the lower resection margin showed exclusively submucosal structures. To exclude residual tumor, two biopsies were taken from the remarkably uneven resection site. These additional biopsies consisted of submucosa and muscularis externa.

Figure 1 The resection site after the cap aspiration procedure in a 67-year-old patient.

One day after the intervention, the patient developed a massive retroperitoneal perforation, with gas accumulations in the perirectal area (Figure [2]), abdominal wall, and mesenteric area, as shown by computed tomography. Since she was asymptomatic, conservative treatment with intravenous antibiotics and isotonic fluid was chosen. Complete resolution of the gas accumulations was documented 7 days later.

Figure 2 Perirectal gas accumulations were observed 1 day after treatment.

It is not clear whether the perforation was caused by the additional biopsies or by the resection itself.

In these two cases, strip or piecemeal snare resection would definitely not have allowed complete resection. The cap aspiration method is therefore extremely helpful in ensuring thorough treatment of rectal carcinoids, but like any interventional method it is also associated with a considerable risk - namely perforation.

This reported case suggests that the practice of taking additional biopsies after resection should be discouraged. To facilitate conservative treatment of possible perforation, complete bowel cleansing should be carried out before the intervention, despite the distal location of these lesions.

Reference

• 1 Nagai T, Torishima R, Nakashima H. et al . Saline-assisted endoscopic resection of rectal carcinoids: cap aspiration method versus simple snare resection.  Endoscopy. 2004;  36 202-205