EP22.06: Appendiceal mucocele due to low‐grade mucinous neoplasm presenting as an adnexal mass

We present a case of a 42-year-old asymptomatic woman, with a medical history of celiac disease, who was referred to our ultrasound unit for evaluation of a mass in the right adnexal fossa discovered at her annual gynecological exam. An elongated unilocular formation, measuring 70mm × 22mm x 28mm, with regular borders, predominantly hypoechoic heterogeneous content and colour score 2 was observed (see figure 1). The mass was contacting the normal right ovary and uterus, being separable from both under the ultrasound probe pressure. This finding on dynamic ultrasound raised the suspicion of a non-gynecological lesion. Ascites, peritoneal metastases or other alterations were not observed. Abdominal-pelvic magnetic resonance imaging considered the lesion compatible with an appendiceal mucocele. Colonoscopy evidenced normal appendicular orifice (negative multiple local biopsies). During the explorative laparoscopy, normal morphology of the internal reproductive organs was noted. Appendiceal mucocele involving the entire appendix was diagnosed. Inspection of the abdominal cavity revealed no other pathological findings. Appendectomy with the excision of mesoappendix was performed (histology: low-grade appendiceal mucinous neoplasm, LAMN, T3 with positive surgical margins). The patient was scheduled for a right hemicolectomy. We previously published a case of LAMN mimicking a solid, regular and heterogeneous right adnexal lesion with colour score 2. Gynecologists and other pelvic imagers and surgeons should be familiar with the ultrasound characteristics of appendiceal lesions, including LAMN, to provide the patients with appendiceal pathology with a timely diagnosis and optimal management. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.