Appendiceal mucocele mimicking urolithiasis

Appendiceal mucocele is a rare clinical condition that results from distension of the appendix lumen with mucus. It is only found in 0.1-0.3% of all appendectomy specimens. Twenty-five per cent of these cases are asymptomatic and are incidentally discovered either during surgery or upon radiological examination. The treatment of appendiceal mucocele is surgical, and while appendectomy is usually sufficient in some cases right hemicolectomy may be considered as a treatment option. Mucoceles are histologically subdivided into four types: retention cysts, mucosal hyperplasia, cystadenomas and cystadenocarcinomas. Herein, we present a case of appendiceal mucocele clinically mimicking urolithiasis in a 62-year-old female patient with a complaint of colicky right flank pain and a single episode of macroscopic hematuria. The patient's abdominal ultrasonography and abdominal CT scan showed a mass consistent with mucocele in the right lower quadrant of the abdomen. Colonoscopy gave the impression of a mass lesion exerting pressure from the outside. The patient was electively operated. Histopathological diagnosis was reported as mucinous cystadenoma. Appendiceal mucocele or mucinous cystadenomas are usually seen in patients undergoing surgery with a diagnosis of appendicitis but, as in our case, these lesions may rarely occur with a clinical picture that mimics urological disease.