Mucocele of the Appendix - A Heterogenous Surgical Pathology

Background: Mucoceles of the appendix are rare. After appendectomy, mucoceles are detected with a frequency of 0.2 to 0.3%. Both stenosing/obliterating processes and alterations of the epithelium (hyperplasia, mucinous cystadenoma, cystadenoma with uncertain malignant potential (UMP), mucinous cystadenocarcinoma lead to the occurrence of mucoceles. The perforation of a mucocele with possible spread of mucus and cells into the abdominal cavity constitutes a severe complication (pseudomyxoma peritonei). Surgical resection is the curative approach for mucoceles of the appendix. Materials and Mathods: Data of patients who were treated for an appendiceal mucocele between 1995 and 2009 were analysed retrospectively with regard to clinical presentation, diagnostic measures, surgical procedure and histopathological result. Follow-up was evaluated in telephone interviews. Results: We extracted 5cases from our database. Clinical symptoms varied greatly among the individual patients, ranging from peracute abdominal pain in the right lower quadrant to chronic obstipation. Results from abdominal ultrasound and/or abdominal CT scans contributed to the indication for surgical intervention in all cases. In 2patients surgery was stated as urgent whereas in 3 the operation was scheduled electively. In one patient the diagnosis of an appendiceal mucocele was stated preoperatively and in another intra-operatively. In 3patients only the histopathological result revealed the underlying mucocele. We performed 1open and 1laparoscopic appendectomy, 1open appendectomy with a partial resection of the coecum and 2laparoscopic ileocoecal resections. One of the patients had a pseudomyxoma peritonei. The histopathological diagnoses ranged from mere epithelial hyperplasia to an adenoma with uncertain malignant potential and a mucinous cystadenocarcinoma. One patient's long-term follow-up could not be evaluated. All other patients had neither recurrence nor any complications after discharge. Conclusions: Mucoceles of the appendix present with a wide spectrum of clinical symptoms and histopathological alterations. Only an accurate histological analysis reveals the underlying pathological lesion correctly. This study emphasises that a mucocele of the appendix constitutes an important differential diagnosis in patients presenting with pathologies in their right lower abdominal quadrant.