Ovarian dysgerminoma detected by 18F-FDG PET/CT technique: A case report.

Introduction: Ovarian dysgerminoma (OD) mostly affect young women, have a rapid growth rate, and could result in complications such as rupture, hemoperitoneum or torsion, and acute abdomen. However, there have been no reports of OD on F-FDG PET/CT imaging.

Patient Concerns: A 21-year-old female patient was admitted to our hospital on February 6, 2016, due to "reduced menstrual flow with abdominal distension for 3 months".

Diagnosis: Color Doppler ultrasound showed a large solid mass in the abdomen and pelvis. Serum carbohydrate antigen 125 (CA125) was elevated significantly. Subsequent computed tomography (CT) of chest showed a large effusion in the right thoracic cavity. Abdominal CT scan revealed the presence of a solid mass occupying a large space in the middle and lower abdomen, suggesting that it derived from the left ovary. Then, she underwent F-fluoro-2-deoxy-D-glucose (F-FDG) positron emission tomography (PET)/CT examination for further diagnosis and staging. PET/CT showed a large occupying lesion in the abdomen. The maximum standardized uptake (SUVmax) of F-FDG was 15.8. No obvious hypermetabolic metastases were observed in the other parts of the body. Postoperative pathology and immunohistochemistry confirmed the ovarian dysgerminoma.

Interventions: The patient underwent surgery. Chemotherapy was successfully carried out post-operation.

Outcomes: Fortunately, the patient is responding well to treatment and the postoperative recurrence-free survival time has been more than 3 years.

Conclusion: OD usually occurs in young women and is characterized by large solid pelvic mass. The F-FDG PET/CT scan shows abnormally increased metabolism of the tumor. Because of the high metabolic characteristics, F-FDG PET/CT may be of great significance in the diagnosis and staging of OD.