[18-year-old woman with an ovarian tumour detected by coincidence].

Massive ovarian edema (MOE) is a rare, benign disease of young women. Because preoperatively in most cases the differential diagnosis primarily appears to indicate the presence of a malignant tumour, there is a risk that these patients will be subjected to unnecessary overtreatment. In the case of the 18-year-old patient described here, on the basis of the preoperative data the suspected clinical diagnosis was polycystic ovarian (PCO) syndrome. In the MRI the enlarged ovary was interpreted as a mucous tumour. The laparotomy showed a smooth-walled, opalescent ovarian tumour with adnexal torsion. Histopathological examination of the adnexectomy specimen gave the diagnosis of a massive ovarian edema (MOE). Therapeutically, a wedge-shaped excision, immediate-section histology and derotation and suspension of the ovary would have been sufficient. Unnecessary overtreatment can be avoided in young women with enlarged ovaries, if MOE is included in the differential diagnosis and if the characteristic sonography, MRI and macroscopy findings are known.