Introduction and importanceBenign multicystic peritoneal mesothelioma is rare, with around 200 cases reported in the literature.We report the case of a patient operated on for the diagnosis of cystic lymphangioma but the pathology examination retained the diagnosis of benign cystic peritoneal mesothelioma.Case presentationA 47-year-old patient, who consulted for abdominal distension evolving for a year. Examination revealed a 30-centimeter abdominal mass. The CT scan showed an intraperitoneal cystic mass measuring 24 × 13 × 32 cm. The diagnosis of cystic lymphangioma was suspected and we decided to surgically remove the mass. We performed a laparotomy. There was a large multi-cystic formation that seemed to develop at the expense of the parietal peritoneum and the greater omentum. A monobloc resection was performed. The postoperative was eventless. Pathology concluded to a benign cystic peritoneal mesothelioma.DiscussionThe BMPM is a rare peritoneal neoplasm that develops mainly in women, during sexual activity. Its etiopathogenesis is unknown. It is often mesenteric or omental.Generally, resection is considered the sole treatment for benign mesotheliomas. However, this surgery needs to be R0 or it will expose to a certain recurrence.Some authors recommend a more aggressive approach associating cytoreductive surgery with heated intraperitoneal chemotherapy.ConclusionBenign multicystic peritoneal mesothelioma is a rare pathology of the peritoneum which develops mainly in women during periods of reproductive activity. Despite its benignity, it presents a high risk of recurrence, up to 50 % of cases.