[Appendiceal mucocele misdiagnosed with infected urachal cyst: a differential diagnosis to keep in mind]. / Mucocele apendicular confundido con quiste de uraco infectado: un diagnóstico diferencial a tener en cuenta.

OBJECTIVE: To report one case of appendiceal mucocele misdiagnosed with an infected urachal cyst and to review their differential diagnosis, treatment and prognosis. PATIENT: We report the case of a 74-year-old-male with abdominal pain, fever and dysuria. Hypogastric abscess image in ultrasonography and CT. Percutaneous drainage and antibiotic therapy. Opaque enema, colonoscopy and cystoscopy were normal. RESULTS: Exploratory laparotomy and resection of a large cecum-fixed mass, independent to the bladder. Appendectomy and cecectomy. Pathology showed an appendiceal mucinous cystoadenoma (mucocele). CONCLUSIONS: Appendiceal mucoceles and urachal cysts are uncommon, mostly asymptomatic. Cystoadenoma or cystoadenocarcinoma mucoceles are large and can reach the midline, confounding with urachal cysts. Diagnosis by ultrasonography and/or CT. Surgical treatment in both, keeping the mucocele intact during operation to avoid the risk of pseudomyxoma peritonei.