Article Text

A case of ureteric obstruction, retroperitoneal fibrosis, and carcinoid tumour

Abstract

We report the incidental finding at surgery for retroperitoneal fibrosis of a carcinoid tumour causing complete right ureteric obstruction. Retroperitoneal fibrosis is an uncommon inflammatory disease that leads to extensive fibrosis throughout the retroperitoneum. It can occur at any age, peak incidence being in patients between 40 and 60 years of age. Carcinoid tumours arise from enterochromaffin or amine precursor uptake and decarboxylation cells that occur in gastrointestinal tract. Carcinoid tumours are an uncommon clinical entity and incidence varies with gender and age. No association between retroperitoneal fibrosis and carcinoid tumour has been previously reported in the English literature, although one case has been reported in a French journal.

  • retroperitoneal fibrosis
  • carcinoid tumour
  • ureteric obstruction

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Retroperitoneal fibrosis1 is a rare inflammatory disease that involves soft tissues in the retroperitoneum. The condition was first described by Ormond in 1948. In the early stages of retroperitoneal fibrosis, there is active chronic inflammation.2 Large numbers of lymphocytes, plasma cells, and macrophages are interspersed in a framework of fibroblasts and collagen bundles. In late stages, there is progression to fibrous scarring. The tissue becomes avascular and acellular with scattered calcification amongst collagen bundles. Ureteral, nerve, aortic and iliac artery compression is frequently described.

The pathogenesis of retroperitoneal fibrosis remains unclear.3 Location and pathologic appearance of disease suggests an immune reaction. Carcinoid tumours arise from enterochromaffin or amine precursor uptake and decarboxylation cells that occur commonly in gastrointestinal tract4 but also ovaries, testes, thymus, pancreas and hepatobiliary system. Carcinoids form only part of a spectrum of neuroendocrine tumours.5They have the ability to synthesize and secrete a variety of neuroamines and neuropeptides and should all be regarded as potentially malignant.

We describe a case of retroperitoneal fibrosis around the right ureter and an incidental finding of nearby carcinoid tumour of the ileum.

Case report

A 61-year-old Caucasian man presented with a few weeks history of dysuria, haematuria, pain in right groin and back pain. Intravenous urography demonstrated a dilated right ureter down to L3 with complete cut off (figure 1). A retrograde pyelogram showed right upper tract dilatation and complete obstruction, which seemed to be extramural. No luminal or mucosal cause was seen and therefore a stent was inserted. A computed tomography (CT) scan of the abdomen then showed right hydronephrosis and soft tissue thickening around the right ureter (figure 2). He did not have any relevant medical history or gastrointestinal symptoms and was a non-smoker. On the basis of the scan, it was decided that the diagnosis was most probably retroperitoneal fibrosis and therefore exploration of the right ureter was planned. Laparotomy through a mid-line incision confirmed the presence of a dense fibrous tissue mass around the right ureter from the upper to middle third, and also demonstrated a plaque in the terminal ileum near the fibrosis side. Ureterolysis, omental sleeve and small bowel plaque resection were carried out.

Figure 1

Intravenous urography demonstrating a dilated right ureter down to L3, with a complete cut off

Figure 2

CT scan of the abdomen showing right ureteric stent with both ureters containing contrast medium plus peri-ureteric soft tissue (or ureteric thickening) of right ureter

PATHOLOGY

The material excised from around the ureter showed fat with strands of collagenous fibrous tissue. A number of arterioles with moderately thickened walls were present. Focal lymphocytic aggregations were seen (figure 3).

Figure 3

Retroperitoneal collagenous fibrous tissue with focal lymphoid infiltrate. Elastic-van Giesen × 40

The tissue from the wall of the ileum contained a pale firm nodule 1 cm in maximum dimension. Histology revealed it to be a carcinoid of ‘midgut’ pattern, with sharply demarcated islands of monomorphic cells, with moderate cytoplasm and round nuclei. The base of many of the cells had a granular eosinophilic appearance; these granules could be demonstrated by diazo staining and silver impregnation (figure 4). There was moderate mitotic activity and tumour cells could be seen infiltrating the muscle and serosa.

Figure 4

Small intestine showing infiltration of the mucosa and sub-mucosa by carcinoid tumour. HE, orig × 40

Discussion

This is the first case report of co-occurrence of retroperitoneal fibrosis and carcinoid tumour. Retroperitoneal fibrosis is a rare inflammatory disease that leads to extensive fibrosis throughout the retroperitoneum.6 Two-thirds of patients with retroperitoneal fibrosis are considered to have idiopathic disease, in the rest, the condition is thought to be caused by drugs (eg, methysergide, antihypertensives).

The diagnosis of retroperitoneal fibrosis was based on intravenous urography findings of hydro-ureterionephrosis and extrinsic ureteral compression, considered pathognomonic of retroperitoneal fibrosis. The diagnosis of retroperitoneal fibrosis was supported by CT scan findings and confirmed laparotomy findings and histology. Unfortunately, an erythrocyte sedimentation rate was not measured in our patient pre-operatively, which may have helped in the diagnosis, as this is always significantly elevated in retroperitoneal fibrosis.2 At laparotomy, a lesion in the ileum was also found, near the site of retroperitoneal fibrosis. The histology of the lesion demonstrated carcinoid tumour. This is the first reported case of retroperitoneal fibrosis in association with carcinoid tumour in the English literature, although one case has been reported in a French journal.7

Surgery, as performed in this case, of lysis or bypass is the mainstay of treatment for retroperitoneal fibrosis. The use of steroids was first reported by Ross and Tinckler in 1958. The anti-inflammatory action of corticosteroids and their ability to inhibit fibrotic tissue maturation make them ideal for managing the chronic inflammation of retroperitoneal fibrosis. The main disadvantage of medical management of retroperitoneal fibrosis is lack of histologic proof of diagnosis and exclusion of malignancy.2 Immunosuppressive treatment has been used as an adjunct to surgery or in those unfit for surgery or those who relapse after surgery.

Although our patient did not have features of carcinoid syndrome (eg, flushing, diarrhoea, dyspnoea, etc)5, due to the malignant potential of carcinoid tumour, it is planned that he will undergo more extensive surgical investigation and management.

Summary points

  • retroperitoneal fibrosis is a rare inflammatory disease that involves soft tissues in the retroperitoneum

  • carcinoid tumours arise from enterochromaffin or amine precursor uptake and decarboxylation cells. They synthesize and secrete a variety of neuroamines and neuropeptides which are known to produce changes in the peritoneum. These changes may also affect the retroperitoneum, resulting in fibrosis and obstruction of ureters

  • all carcinoid tumours should be regarded as potentially malignant and treated appropriately

 Further research is required to investigate the causal association between retroperitoneal fibrosis and carcinoid tumour. The secretions of carcinoid tumours are known to produce changes in the peritoneum, which may also affect the retroperitoneum, resulting in fibrosis and obstruction of the ureters. We think it is worthwhile adding carcinoid tumour to the list of aetiological factors leading to retroperitoneal fibrosis. We also recommend considering carcinoid tumours in cases of idiopathic retroperitoneal fibrosis.

References

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