Peritoneal multicystic mesothelioma is a very rare clinical condition. This neoplastic variant has a high incidence of recurrence after surgical resection. It usually occurs in middle-aged women with a previous history of gynaecological surgery and presents with the symptoms of an abdominal or pelvic mass. The case reported here is that of a 58-year-old woman, characterised first by a left liver-lobe tumour and then by a subsequent episode of emission of cystic matter from an abdominal fistula. The relevant literature is reviewed and the clinical aspects and treatment of this disease are discussed.