Imaging of mucocoele of the appendix with emphasis on the CT findings: A report of 10 cases

AIM: Mucocoele of the appendix denotes an obstructive dilatation of the appendiceal lumen due to abnormal accumulation of mucus. It is sometimes associated with pseudomyxoma peritonei, which predicts a malignant origin. We present the CT findings and additional imaging studies of 10 patients with neoplastic appendiceal mucocoele and discuss the clinical implications. MATERIALS AND METHODS: Abdominal CT findings from 10 patients with appendiceal mucocoele were reviewed. Barium enema, US and MRI were additionally performed in three patients. There were five men and five women aged 45-80 years. Special attention was directed to the shape and nature of the mass, its relation to the caecum and the presence of ascites or peritoneal implants, as well as possible additional ovarian tumours in female patients. RESULTS: The mucocoele was an incidental finding in five patients. They were either spherical or elongated cystic lesions, attached to the wall of the caecum, six of them with mural calcification. Ascites were present in six patients and hypodense large peritoneal implants representing pseudomyxoma peritonei in four. Pathologically the series included five cases of cystadenoma (in one, a malignant pseudomyxoma peritonei subsequently developed), four cases of cystadenocarcinoma and one villous adenoma (this patient later developed pseudomyxoma peritonei). Pseudomyxoma peritonei was found in five cases. Three women had associated ovarian cystic tumour. CONCLUSION: The appearance of an appendiceal mucocoele is quite characteristic and can be diagnosed on CT. CT can also depict additional findings suggesting pseudomyxoma peritonei. In women with an appendiceal mucocoele the ovaries should be examined closely for cystic tumour and vice versa.