Clinical
Radiology
(1999)
54, 331-339
Case Reports Solitary Caecal Ulcer Syndrome, a Benign Condition which Mimics the CT Appearance of Caecal Carcinoma PATRICK
M. RAO”,
ROBERT
A. NOVELLINE”,
LAWRENCE
ZUKERBERGf
Departments of *Radiology and l-Pathology, Massachusetts General Hospital, Boston, Massachusetts, U.S.A.
Solitary (or idiopathic) caecal ulcer syndrome is a rare entity whose initial clinical presentation usually suggestsappendicitis. Imaging with barium enema or computed tomography (CT) may suggest caecal carcinoma. Definitive diagnosis is made at pathology. In this report we describe the clinical, radiological and pathological findings of a patient with solitary caecal ulcer syndrome, and illustrate the CT and pathological findings in a second patient.
CASE REPORT A 76-year-old woman presented to the Emergency Department with a 4-day history of acute right lower abdominal pain and nausea. It was unclear whether her appendix had been removed at the time of a previous oophorectomy. On physical examination, her abdomen was soft, with right lower quadrant guarding and tenderness to palpation, but no rebound tenderness. The clinical impression was appendicitis with possible perforation. CT examination performed after oral, rectal and intravenous contrast media demonstrated a caecal lesion with wall thickening and luminal narrowing (Fig. la). Noted just inferior to the caecum was a 3 x 3 cm collection of extraluminal air and fluid with an enhancing rim, consistent with an abscess (Fig. lb). The appendix was not identified. Perforated appendtcitis, caecal carcmoma, and ischaemic colitis were considered in the differential diagnosis. A water-soluble contrast enema was then performed which demonstrated a sharply marginated stenosis and loss of the normal mucosal pattern in the caecum, interpreted as ‘suggestive of caecal carcinoma or an inflammatory or ischaemic caecal process’ (Fig. lc). A right hemicolectomy was urgently performed. The hemicolectomy specimen revealed a 2.5cm discrete ulcer in the caecum with necrosis, perforation and pericaecal abscess formation. There was no evidence of neoplasia, granulomas, or parasites, nor was the appendix present. The patient’s recovery was uneventful, and she was discharged 2 weeks later.
DISCUSSION
Solitary caecal ulcer syndrome is an uncommon entity without characteristic clinical or radiological findings, and it is rarely diagnosed pre-operatively [l]. Definitive diagnosis is nearly always made at pathology. 0009.9260/99/050331+09
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Approximately 50% of solitary colonic ulcers are found in the caecum, usually antimesenteric, within 2cm of the ileocaecal valve [2]. Approximately 200 cases of solitary caecal ulcer have been reported in the literature to date. Various aetiologies have been proposed for ulcer formation, including medications, ischaemia, cytomegalovirus, other infections and stasis of colonic contents in the caecum [3-51. The most common cause of caecal ulceration is carcinoma, and this must be excluded along with inflammatory bowel disease, systemic vasculitis, tuberculosis, and amoebiasis or other parasites before the ulcer can be considered idiopathic [3,4]. Clinical presentation varies widely. Right lower quadrant pain, either acute or chronic, is the most common symptomatic presentation. Hematochezia, constipation, diarrhoea, weight loss and/or intestinal obstruction may also be present. With bowel perforation and abscess formation, the patient can present with an acute abdomen. The ulcer may also be asymptomatic and discovered incidentally during colonoscopy [31.
When patients present acutely, appendicitis is most frequently the pre-operative diagnosis [2,3]. Less commonly, inflammatory bowel disease or perforated carcinoma may be the leading clinical diagnosis. Chronic abdominal pain and/or gastrointestinal haemorrhage may raise the possibility of diverticulosis, diverticulitis or occult colon carcinoma. Findings of solitary caecal ulcer have been described on angiography, barium enema and CT. Angiographic findings include abnormal terminal branches, early venous filling, and contrast pooling in the ulcer [6]. These findings overlap with the more common entity angiodysplasia. Contrast enema examinations performed on patients with solitary caecal ulcer demonstrate an abnormality in approximately 75%. Changes include luminal narrowing, mucosal irregularity and/or ulcer crater formation, and are usually interpreted as caecal carcinoma [7]. CT findings of solitary caecal ulcer have been reported in two patients [l]. Both demonstrated caecal wall thickening, diffuse in one case and eccentric in the other, with adjacent fat stranding. These findings are non-specific, reflecting inflammation of the caecal wall and pericecal fat. Differential 0 1999 The Royal
College
of Radiologists
332
CLINICAL
RADIOLOGY
@I
Fig. 1 - Solitary caecal ulcer syndrome. (a) CT image reveals concentric wall thickening and enhancement (arrows) is luminal narrowing in the caecum, and adjacent fat stranding. (b) An extraluminal collection of gas and fluid with an enhancing rim (arrows) is also noted, consistent with an abscess due to bowel per-formation. (c) Image from a barium enema examination in the same patient demonstrates a sharply marginated stenosis (arrows) in me caecum, suggestive of annular carcinoma.
possibilities include caecal carcinoma, diverticulitis, appendicitis, typhlitis, and infectious or ischaemic colitis. Wall thickening and fat stranding in the presence of caecal divert&la can suggest diverticulitis. Appendicitis will usually demonstrate a dilated, nonfilling appendix, occasionally with associated appendolith, in addition to caecal wall thickening and local fat stranding.
However, the CT findings of solitary caecal ulcer are strikingly similar to those seen with caecal carcinoma. The CT findings of solitary caecal ulcer are illustrated in Fig. 1, including wall thickening and enhancement, and pericecal inflammation. The CT and pathological findings of another patient with solitary caecal ulcer are also illustrated
333
CASE REPORTS
(Fig. 2). This second patient has been more completely discussed in a previous report [8]. At pathology, an ulcer crater or superficial erosion with surrounding nodular, edematous and indurated mucosa may be noted. Multiple biopsies are performed to exclude amoeba, granulomas, mycobacterium, or malignancy. Pathologically, the most striking feature of solitary caecal ulcer syndrome is identification of a caecal ulcer without evidence of carcinoma or infection. Management of patients with solitary caecal ulcer depends on the clinical presentation. In the presence of perforation with abscessformation or peritonitis, or with massive gastrointestinal bleeding, immediate surgery is warranted. An ulcer, with no evidence for malignancy, discovered at the time of surgery may be treated without further intervention by stapler-wedge caecectomy or more extensive right hemicolectomy. In summary, solitary caecal ulcer syndrome should be included in the differential diagnosis when CT imaging demonstrates diffuse or eccentric wall thickening with adjacent fat stranding. Definitive diagnosis can only be made pathologically, either by endoscopic biopsy, caecal biopsies or by examination of the resected specimen.
REFERENCES
@I Fig. 2 - Solitary caecal ulcer syndrome. (a) CT image in a 71-year-old woman with a 2-day history of acute onset of right lower quadrant pain demonstrates eccentric wall thickening (arrows) along the medial aspect of the caecum. (b) Macroscopic pathology of the caecum reveals a discrete ulcer (arrows) with heaped up, hyperemic margins.
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