EP22.16: Squamous cell carcinoma arising in an ovarian mature cystic teratoma: a case report

Malignant transformation of ovarian mature cystic teratomas (MCTs) is rare, accounting for 0.16-2% of cases and squamous-cell ovarian carcinomas (SOCs) represent the 80% of them, followed by adenocarcinomas and sarcomas. Differently from MCTs, SOCs have a worse prognosis and are more often diagnosed at advanced stages. A 50-year-old woman reporting pelvic pain came to our Department for presurgical evaluation. MRI detected a right adnexal mass with adipose tissue in the contest, referable to a dermoid cyst. CA-125 was 70 UI/mL, CEA was 22.3 ng/mL and CA-19.9 was 168 UI/mL. Transvaginal ultrasound examination showed a right adnexal unilocular solid lesion of 95x76x91mm with mixed content. The solid component of 28x20x24mm with inhomogeneous echostructure was richly vascularised at colour Doppler. Patient underwent a laparoscopic hysterectomy and bilateral salpingo-oophorectomy. The intraoperative frozen section detected atypical cells. Surgery was converted to laparotomy and pelvic peritonectomy, omentectomy and lymphadenectomy were performed. Final histology report was positive for invasive squamous ovarian cancer high grade (G3) arised on mature ovarian teratoma. Macroscopically the tumour was predominantly cystic with a minor solid component. The cystic component was filled with a yellowish liquid, sebum and hair. Pelvic peritoneum was infiltrated by carcinoma, so FIGO stage was IIB. After collegial discussion, the patient was planned for adjuvant chemotherapy. In conclusion, SOC arising from MCT is a very rare disease and diagnosis is still challenging. The ultrasound detection of a vascularised solid component was helpful for the suspicion of malignant transformation. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.