Multiple Revascularizations of Intestinal Arteries to treat Mesenteric Ischaemia due to Carcinoid Tumor
Article Outline
Although rare, carcinoid tumors are the most common type of neuroendocrine tumors. Mesenteric metastases are common and may cause intestinal ischaemia. Circular growth around the superior mesenteric artery may hinder surgical resection of the tumor. We report the first case in the literature where such a carcinoid tumor was resected followed by mesenteric revascularization by multiple vascular anastomoses to small visceral arterial branches.
Keywords: Mesenteric ischaemia, Visceral artery revascularization, Carcinoid tumor
Introduction
The term carcinoid was first applied a century ago to a distinct gastrointestinal neoplasm that appeared to be less aggressive than adenocarcinomas.1 Carcinoid tumors are most common in the terminal portion of the small intestine.2, 3, 4 The primary tumor is often a small submucosal lesion, and it may appear at surgery only as a localized fibrotic induration on the intestinal serosa.2, 4 Mesenteric metastases are frequent and they are usually larger than the primary tumor.2, 4 The fibrosis around mesenteric metastases tends to cause shrinkage of the mesentery.4 In advanced disease, the mesenteric vessels may also become encapsulated, and this results in intestinal ischaemia.4, 5
We present a patient with a mesenteric carcinoid tumor causing stenosis of the superior mesenteric artery (SMA).
Case Report
A 66-year-old woman had had upper abdominal pain and periodical diarrhoea for several years. A computed tomographic (CT) scan was taken at a local hospital in June 2004 (Fig. 1) which showed a tumor in the mesentery and encroaching of the superior mesenteric artery. The CT finding suggested a carcinoid tumor. This diagnosis was corroborated by a high urinary excretion of 5-hydroxyindolacetic acid (5-HIAA) and high plasma levels of chromogranin-A. Although there were no obvious liver metastases, the size of the tumor was such that it was initially considered to be unresectable. Since the tumor was clearly positive on somatostatin receptor scintigraphy, treatment was started with monthly intramuscular injections of long-acting octreotide. Despite this treatment the patient had progressive abdominal pain and was referred to our hospital for a second opinion a few months later. The pain was assumed to be partly due to mesenteric ischaemia. Surgery was now considered necessary and was offered as an option to the patient. She agreed to an operation.
Fig. 1
Computed tomographic scan showing a carcinoid tumor with circumferential growth around the superior mesenteric artery.
The patient was operated on in July 2005. During the operation octreotide was infused intravenously to prevent carcinoid crisis. The tumor was located in the mesentery of the small intestine: the mesentery was shrunken around the tumor which therefore was considered to be inoperable. However a long segment of the small intestine became seriously ischemic, despite gentle handling during surgical exploration. Due to this new development it was decided to continue the operation and remove the tumor. Because the tumor infiltrated the SMA circumferentially, the SMA had to be ligated proximally. The ascending colon and approximately two meters of the distal small intestine were removed; the most distal 30
cm of the ileum was preserved. The remaining small intestine had a narrow mesentery with a width of only 5–10cm and lacked proper arterial feeding. Arterial revascularization was required: two saphenous vein grafts were used and the inflow was taken from the right iliac artery. Seven small openings were placed on the side of the vein grafts for constructing the anastomoses between the vein grafts and the very small mesenteric arterial branches (Fig. 2). After revascularization the colour of the small intestine became normal. However, the distal 30cm of the small intestine started to turn blue and oedematous regardless of a good arterial flow. This was due to ligation of the small intestinal mesentery at the site of the bowel anastomoses, which inhibited the venous outflow (Fig. 2). In this situation the distal 30cm of the small intestine had also to be removed. The length of the remaining small bowel was 1.5 meter.
Fig. 2
Revascularization of mesentery with vein grafts. The distal 30 cm of ileum (darkened in the drawing) was removed, because there was no venous outflow.
When the bowel was returned into the abdominal cavity there were serious problems of vein graft kinking. A number of new vein-to-vein anastomoses had to be done to reduce the lengths of the vein grafts and to avoid vessel rotation and to prevent kinking. Performing these very small anastomoses was time consuming: the operation took 13 hours and 50 minutes.
On the next day a second-look laparotomy was performed. The grafts were patent and the bowel looked healthy except for the first 30cm of jejunum which looked ischemic and was removed. Because the venous blood flowed along the mesentery in a proximal direction, the bowel resection had to be done without any further resection of the mesentery.
The patient recovered uneventfully and was discharged to a local hospital on the seventh postoperative day. According to CT-angiography, the vein grafts were open 2 months after the operations (Fig. 3).
Fig. 3
Computed tomographic angiography 2 months postoperatively. The grafts are open.
Histologically, the carcinoid was a well differentiated neuroendocrine carcinoma with low-grade malignancy.
One year and four months after the operation the patient is doing well. She has gained weight, has no abdominal pain and her diarrhoea is well controlled.
Discussion
The clinical presentation of jejuno-ileal carcinoids differs from the presentation in other sites of the gut, since small-bowel carcinoids tend to be detected at an advanced stage.3 Still, small-bowel carcinoids are the most common cause of the carcinoid syndrome, which is characterized by flushing, diarrhoea, and valvular heart disease.4 Often the carcinoid syndrome becomes clinically manifest only when hepatic metastases have developed.2
Abdominal pain is often the presenting symptom of patients with carcinoid tumor, but – as shown by the present patients report – abdominal pain may also be due to bowel ischaemia.5 Intestinal ischaemia is rare, it is therefore not always considered as a cause of abdominal pain in patients with carcinoid.5
The primary treatment of carcinoid tumor is surgical excision and even in patients with metastases, tumor debulking and resection may alleviate symptoms and prolong survival.3, 6 In most patients the primary tumor and adjacent mesenteric metastases are easily removed by wedge resection and limited intestinal resection,4 but occasionally the tumor is bulky and appears inoperable if it extends high into the mesenteric root, especially if it grows circumferentially around the SMA.
The tumor of our patient grew circumferentially around the SMA and the artery had to be ligated for tumor removal. Since much of the mesentery had shrunk around the tumor and had to be resected, gangrene of the small intestine was likely to ensue, because collateral flow was not adequate to re-establish the circulation for remaining bowel. Therefore, the intestinal arteries distal to the ileocolic bifurcation had to be revascularized one by one.
The literature reports only isolated cases of extensive mesenteric revascularization. Öhrvall et al. reported one patient in whom they had done a bypass between the right iliac artery and the first ileo-colic arcade with a PTFE graft and a distal vein cuff.4 In our case we did several small end-to-side anastomoses between the saphenous vein grafts and the mesenteric arteries. Our case shows that mesenteric artery revascularization is feasible even to very small mesenteric arterial branches and that the venous outflow may pass along the 5–10cm broad mesentery. On the second look laparotomy it was extremely important that the further bowel resection was done without any resection of the mesentery to save the venous flow.
The carcinoid tumors progress slowly and the course of disease is extended. Surgery should aim at removal of mesenteric metastases, since the metastases may cause severe long-term abdominal complications through fibrotic entrapment of the intestine and small-bowel ischaemia following compression of the mesenteric vessels. Attempts should also be made to surgically remove or ablate liver metastases, since considerable palliation may be offered.2 The present patient did not have any liver metastases at the diagnosis, which further supported our decision to attempt tumor removal. Furthermore, the combination of surgery and pharmacotherapy with long-acting somatostatin analogues and interferon-alpha may slow the progression of the disease, and increase survival and the quality of life of the patients.2
Acknowledgement
We thank Anita Mäkelä, RN, for assistance and drawing the pictures.
References
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- . Midgut carcinoid tumors: surgical treatment and prognosis. Best Pract Res Clin Gastroenterol. 2005;19:717–728
- . Current status of gastrointestinal carcinoids. Gastroenterology. 2005;128:1717–1751
- Method for dissection of mesenteric metastases in the mid-gut carcinoid tumors. World J Surg. 2000;24:1402–1408
- Abdominal angina in patients with midgut carcinoid, a sign of severe pathology. World J Surg. 2005;29:1139–1142
- Surgical treatment of advanced-stage carcinoid tumors: lessons learned. Ann Surg. 2005;24:839–845
PII: S1533-3167(06)00087-2
doi:10.1016/j.ejvsextra.2006.10.005
© 2006 Elsevier Ltd. All rights reserved.
Refers to article:
- Multiple Revascularizations of Intestinal Arteries to Treat Mesenteric Ischaemia due to Carcinoid Tumor , 30 December 2006
