А case of a mucocele of the appendix - A diagnostic and therapeutic dilemma

Mucocele of the appendix is a rare pathology with an estimated incidence of less than 1 % of all appendectomies. Here is a report of a 67-year-old Bulgarian female, diagnosed with a low-grade appendiceal mucinous neoplasm (LAMN) after immunohistochemical analysis, which changed the therapeutic strategy.

We present a case of a patient, initially admitted to the Gastroenterology Department due to complaints of dyspepsia and intermittent watery diarrhea. Abdominal ultrasound revealed an oval hypoechoic heterogeneous formation with mixed echo structure in the ileocecal region. Laparoscopic appendectomy with partial cecal resection was performed. The additional immunohistochemical assessments classified the finding as a LAMN with 12 % proliferative index (Ki-67), pancreatin-positive reaction in epithelial cells and CD68-positive reaction in macrophages.

Mucinous neoplasms of the appendix are classified on a spectrum from benign to malignant based upon certain features on histological examination. When there are signs of malignancy such as metastases in the loco-regional lymph nodes, perforation with intraperitoneal dissemination and affected base of the appendix (positive margins of resection), more aggressive approach is recommended - right hemicolectomy. Simple appendectomy is the choice for patients with benign mucocele as suggested by the presence of a normal caecum and appendicular base with no evidence of perforation.

Appendiceal mucocele could be an illustrative example of a diagnostic and therapeutic challenge due to the rarity of the disease. Pathohistological examination and mainly immunohistochemical tests are the key to correct diagnosis and treatment.