Massive Collision Tumour of the Ovary: A Rare Case of Mature Teratoma and Serous Papillary Cystadenoma

Aims: Collision tumours of the ovary are rare. A pre-surgery diagnosis is possible when there is a high index of suspicion during patient evaluation. This case report highlights the need for this clinical care, evaluation and treatment.

Presentation of Case: A 51 year old Para 7 lady presented at two years post-menopausal with a massively distended abdomen of 4 years duration. A diagnosis of ovarian tumour (likely benign) was made. She subsequently had exploratory laparotomy, total abdominal hysterectomy and bilateral salpingo-oophorectomy. Histopathological assessment revealed a benign collision tumour of the ovary.

Discussion and Conclusion: The case presented had a histological diagnosis of both a mature teratoma and a serous papillary cystadenoma. These are both benign ovarian tumours (germ cell tumour and epithelial cell ovarian tumour respectively). The occurrence of two primary neoplasms in the same organ is called a collision tumour. The clinical presentation and pre surgery investigations were not helpful in making a clinical diagnosis of an ovarian collision tumour. Making a clinical preliminary diagnosis of an ovarian tumour from history and examination is usually difficult. Medical imaging is therefore a valuable key, as it provides not only the origin of the tumour but also gives a probable picture of the histological type. Collision tumours are very rare, but having a high index of suspicion is important as making the right preliminary histologic diagnosis could affect the prognosis and management plan.