BACKGROUND Choriocarcinoma is extremely rare malignancy of gestational trophoblastic disease (GTD).Informations on clinicopathologic features,laboratory examination,ultrasonic characteristics and treatment in previous case reports have reported,but MRI characteristics of tubal choriocarcinoma have not yet been reported. CASE A -39-year-old woman gravida 3 para 1 presented to the Department of gynecology with irregular vaginal bleeding and a palpable the left lower abdominal lump for two months following 6 weeks amenorrhoea.The urine pregnancy test proved to be positive.Ultrasound revealed a well-circumscribed round mass in the left adnexal region.Her serum HCG level significantly elevated at 7158 mIU/mL.MRI revealed a round-like well-defined systic-solid mass in the left lower abdomen,with measuring about 72mm×113mm×80mm.Cyst fluid was low and high signal in the T1WI and T2WI respectively.Solid part in the behind of cystic with small internal components and intracystic papillary node were found,which showed slightly higher and equal signal in the T1WI and T2WI respectively.T2WI showed similar the left ovarian signal located below the mass and the left uterine horn pulled by the mass to upper lefter direction.DWI showed that solid components were high signal.A provisional diagnosis of left ovarian serous cystadenocarcinoma was made.CT showed several round shaped nodules in the whole lung field.Total abdominal hysterectomy,bilateral salpingo-oophorectomy and multiple specimens were performed.Histopathologic examination showed tubal choriocarcinoma.After the operation and four courses of chemotherapy,the HCG level returned to normal.A chest CT showed decreased size and number of nodules.CONCLUSION In summary,the main purpose of this case report is to cause radiologists understanding of MRI characteristics of choriocarcinoma,which diagnosed should combine with obstetrical history,clinical symptoms and HCG value.