BACKGROUND Primary appendiceal tumors are histologically diverse and have an insidious onset and few specific clinical manifestations. In the majority of cases, these tumors are discovered after appendectomy during pathological exam of the resected tissue. Treatment may include appendectomy (simple or radical) and right hemicolectomy depending on factors such as histological type, tumor size and lymph node/organ involvement. The aim of this case study is to describe a rare case of a giant appendicular mucocele and raise awareness of this condition and its management options and follow-up protocol. METHODS We present the case of a 43-year-old patient who presented to our emergency department with mild right lower quadrant pain. After the initial check-up and imaging exams, he underwent surgery, where a giant 20 cm × 13 cm appendicular tumor was found and resected. Appendicular mucocele was suspected due to the macroscopic appearance and was later confirmed by the pathological exam. The patient's postoperative evolution was uneventful, and after discharge, he was included in our follow-up program. CONCLUSIONS In conclusion, mucinous appendiceal neoplasms embody a rare pathology; they are asymptomatic or have few, unspecific clinical signs and in many cases are discovered after appendectomy.