Appendiceal mucocele simulating an ovarian tumor: a case report

¹Department of Gynecology and Obstetrics, Mohammed V Military Training Hospital, Rabat, Morocco

^&Corresponding author
Benali Saad, Department of Gynecology and Obstetrics, Mohammed V Military Training Hospital, Rabat, Morocco

Introduction    

Appendiceal mucocele is a rare entity that is characterized by cystic dilatation in the lumen of the appendix. The diagnosis is often made based on clinical signs and symptoms of acute appendicitis or coincidentally via imaging methods when it is asymptomatic. However, a definitive diagnosis can be rarely made before surgery despite all technical progress in terms of imaging. It may be encountered during abdominal surgery performed for another indication.

Patient and observation     

A 54-year-old woman, menopaused, presented to department of gynecology for isolated chronic pelvic pain. Gynecological examination revealed latero-uterin mass, firm, movable and well limited. Vaginal ultrasonography revealed heterogeneous mass measuring about 60mm with both solid and cystic components, without suspicious vascularity at color Doppler. The MRI revealed suspicious-loading vegetations within the mass (Figure 1, Figure 2). The patient underwent diagnostic laparoscopy that revealed an appendiculus mass measuring 120mm of major axe. Surgical intervention had been converted to laparotomy with appendectomy (Figure 3, Figure 4). Histopathological examination revealed morphological aspect of appendicular mucinous adenoma.

Discussion     

Appendiceal mucocele is a descriptive term referring to distention of the appendix with mucus, which develops secondary to mucinous cystadenoma (63%), mucosal hyperplasia (25%), mucinous cystadenocarcinoma (11%) and retention cysts (1%) of the appendix lumen [1]. Mucocele may also develop when the lumen is obstructed due to endometriosis or carcinoid tumors. It is reported that the incidence of appendiceal mucocele in appendectomy specimens ranges from 0.2 to 0.3 % [2]. Patients are generally above the age of 50, and this condition is four times more common among women [3]. Approximately 25-30% of the patients are symptomatic, and it is accidentally found out during radiological investigation, endoscopic examinations or open surgery [2,4]. The most frequent symptoms in patients with symptomatic appendiceal mucocele is acute or chronic lower right quadrant pain [3]. The mass may be palpated in the lower right quadrant in approximately 50% of the patients [5]. Other symptoms include nausea, vomiting and change in bowel habits [6]. It is quite difficult to make a definitive diagnosis of appendiceal mucocele before surgery as it has non-specific symptoms [7]. Ultrasonography (US) and computerized tomography (CT) may aid in diagnosis. It is generally hypoechogenic on US, yet echogenicity may also be observed depending on the length of acoustic interfaces caused by the mucus. The onion skin-like appearance is specific for appendiceal mucocele [8]. Computerized tomography (CT) is more sensitive in detecting and assessing appendiceal mucoceles. On CT scan, it is observed in the form of a cystic, encapsulated mass with a thin wall, which sometimes has mural calcifications, in the appendix site [9].

There may be synchronous neoplasms with the appendiceal mucocele [10,11]. The most frequent is that of the colon, but it may also be present in other areas such as gall bladder, breast, kidney, ovary and thyroid. In 19.4%-25.4% of the cases, appendiceal mucocele was associated with colon adenocarcinoma [10]. For that reason, patients with appendiceal mucocele should be carefully assessed with focus on the colon neoplasms. The treatment for appendiceal mucocele is surgical. Surgery may be performed via laparoscopy or laparotomy. Preoperatively, surgeon should be aware of the mucocele rupture risk to avoid careless manipulation during surgery; otherwise, a possible rupture during surgery may cause pseudomyxoma peritonei. The 5-year-survival rate with pseudomyxoma peritonei due to mucinous cystoadenocarcinoma may decrease to 20% [12]. Therefore, some publications oppose the use of laparoscopy in mucocele surgery, whereas other publications assert that laparoscopic surgery can be successfully performed [13,14]. The reported case findings and literature indicate that there is no contraindication for laparoscopy in appendiceal mucocele surgery. However, necessary precautions had better be taken to prevent its rupture during laparoscopy [14].

Conclusion     

Appendiceal mucocele is a rare entity with no specific clinical presentation. This makes preoperative diagnosis difficult. Appendiceal mucocele is to be evocated particularly in an elderly woman with an atypical mass like-appearance on US. For patients presenting Appendiceal mucocele, laparoscopic excision performed carefully, following diagnostic laparoscopy is a viable option. In addition, appendiceal mucocele is often associated with colon cancer. Thus, surgeons should manage this case considering the possible concomitance.

Competing interests     

The authors declare no competing interests.

Authors' contributions     

All the authors have read and agreed to the final manuscript.

Figures     

Figure 1: sagittal MRI showing hyperintense rounded mass with vegetations

Figure 2: transversal MRI showing hyperintense rounded mass

Figure 3: macroscopic aspect of appendiculus mass

Figure 4: macroscopic aspect showing the size of the mass

References