Histopathology of Ovarian Collision Tumor: A Rare Case Report

Collision tumour is defined as the coexistence of two or more adjacent but histologically distinct tumours without histological mixture in the same tissue or organ. Collision tumours involving ovaries are extremely rare. Although they have been reported in various organs, ovarian collision tumours are very rare. An ovarian tumour with a cystadenoma or cystadenocarcinoma, typically of the mucinous type, is the most commonly encountered combination. Each component of the collision tumour occurs coincidentally, and no connection is found between the tumours. Our case is a collision tumour of the ovary composed of serous cyst, mucinous cystadenoma, and mature cystic teratoma (dermoid cyst). The aim is to present a rare case. Histopathological processing was done, and Hematoxylin (H) and Eosin (E) stain was used for staining. Though very rare, it is necessary to be aware of collision tumours and the combination of tumours that exist, as the appropriate treatment can then be given to the patient. The most common form of ovarian collision tumour in the literature is the combination with teratoma. Histological recognition of such neoplasms is important, allowing appropriate treatment to be offered to patients according to the individual biological characteristics of each of the components.