Background: Mucinous tumours, the second most common type of epithelial ovarian tumours, are the largest tumours that can be found in the human body. Pseudomyxoma peritonei is a rare clinical entity characterised by progressive accumulation of extracellular mucinous material in the abdominal cavity and tumoural implants on the peritoneal surfaces. Though of controversial origin, ruptured appendiceal mucinous adenoma being most commonly associated with it, mucinous tumours of the ovary have been notable cause (pseudomyxoma ovarii). Patients may present with features of abdominal mass effect among others. Abdominopelvic USS and CT are useful tools for evaluation but definitive diagnosis is often by laparotomy or laparoscopy. Debulking surgery with or without intraperitoneal hyperthermic chemotherapy is the treatment.
Case presentation: A 68-year-old P₄⁺¹ (4 alive) woman, known diabetic and 17 years postmenopausal, presented with a 4-month history of progressive abdominal swelling and discomfort, leg swelling, generalised body weakness and dizziness, early satiety, anorexia, weight loss and bloatedness. She was chronically ill-looking with pedal oedema and abdominal distension. Results of investigations supported ovarian mucinous cystadenoma with low risk of malignancy. She had appropriate surgery with evacuation of 7.5 Litres of clear mucin from the abdominal cavity.  She had a good postoperative course and remained well 18 months later. Histopathology findings confirmed diagnosis with no evidence of malignancy.
Conclusion: Pseudomyxoma peritonei is a rare condition, in association with mucinous cystadenomas; without appendiceal involvement, is even more rare hence may go unrecognized and be fatal if poorly managed.

Keywords: Pseudomyxoma-peritonei (PMP), Pseudomyxoma-ovarii, Mucin, Cystadenomas, Cytoreduction, Chemotherapy.

Cite this article: Oyeyemi N, Agbo OJ, Ohaeri OS, Kofa RI, Egberipou II. Huge ovarian mucinous cystadenoma and pseudomyxoma ovarii/peritonei: A case report. Yen Med J. 2019;1(1):46-48.