© Georg Thieme Verlag KG Stuttgart · New York
Appendiceal mucocele in ulcerative colitis
19 March 2010 (online)
A 55-year-old woman with ulcerative colitis underwent colonoscopy with a view to assess the activity and extent of disease. During the procedure, a 2.5-cm, smooth, rounded lesion ([Fig. 1]) was found in the cecum, distal and separate from the ileocecal valve; the overlying mucosa had a normal appearance.
Fig. 1 Colonoscopic view of the lesion.
A contrast computed tomography (CT) scan of the abdomen showed that the appendix was dilated with low-attenuation fluid to 1.5 cm ([Fig. 2]; arrow) and showed calcification at its origin and tip.
Fig. 2 Computed tomography (CT) scan of the lesion showing a fluid-filled, dilated appendix (arrow).
Based on these findings a diagnosis of mucocele of the appendix was suspected. The patient was referred for laparoscopic resection and a right-sided hemicolectomy was carried out. The surgical specimen included a dilated appendix, 2.8 cm in diameter ([Fig. 3]; arrow); sectioning revealed a 1.3-cm spherical tumour.
Fig. 3 Resected specimen with appendix (arrow).
Histological examination showed this to be a mucinous cyst adenoma with low grade dysplasia ([Fig. 4]).
Fig. 4 Histological section of the resected tumour.
Mucoceles of the appendix are uncommon lesions caused by distension of the appendix with mucinous material. There are four main types: simple or retention mucoceles, hyperplastic mucoceles, mucinous cyst adenomas, and mucinous cystadenocarcinomas . Mucoceles of the appendix can be asymptomatic or present with abdominal pain or bleeding, or as a palpable abdominal mass. Rarely they cause intestinal obstruction, intussusception, ureteric obstruction, volvulus, or cutaneous fistulae . The most feared complication is pseudomyxoma peritonei, because of spontaneous or iatrogenic rupture that results in seeding of neoplastic cells in the peritoneal cavity. Colonoscopy, CT, and ultrasound can all help in diagnosis . As it is difficult to differentiate between benign and malignant lesions causing mucocele, resection is recommended.
There have been case reports of appendiceal mucocele in patients with ulcerative colitis. It has been suggested that appendicular involvement with inflammation, or an associated appendicular neoplasm, in such patients leads to blockage and formation of a mucocele .
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T. Ghosh, MBBS, MRCP
Leeds General Infirmary
Great George Street
Leeds LS1 3EX