Introduction: Ovarian cancer is the second most frequent gynaecological cancer in Nigeria ranking next after carcinoma of the cervix. It has the highest case-fatality rate worldwide because of insidious onset, lack of effective screening methods and late presentation. This case of a sixteen-year old girl with a three-week history of abdominal pain which was later accompanied by abdominal swelling is a classic example of how dysgerminomas present.
Method: The presumptive diagnosis of an ovarian tumour was made after physical examination and this was later confirmed by ultrasound scan. Urgent laparotomy was carried out based on a suspicion of torsion of the pedicle of the cyst.
Result: At laparotomy, torsion of the pedicle with an intact capsule and imminent gangrene were found. The histology report revealed a malignant germ cell neoplasm (Dysgerminoma) with focal areas of necrosis without infiltration of the attached omentum.
Conclusion: She had conservative surgery (left oophorectomy) done. She, however, defaulted from further follow-up.