EP23.36: Malignant transformation of a mature ovarian teratoma: case report

A 60-year-old woman with a clinical history of morbid obesity, arterial hypertension, dyslipidemia and coronary disease (polymedicated for these conditions) was referred to our ultrasound unit due to progressive hirsutism over the last 2 years, a slight increase in serum testosterone and a 4cm right adnexal mass evidenced by abdominal-pelvic CT. Transvaginal (see figure1) and abdominal ultrasound showed a solid formation in the right adnexal fossa, measuring 48 x 40 x 53mm, with irregular contours, heterogeneous echogenicity, regular lacunar spaces, acoustic shadowing and colour score 3. No ascites, peritoneal metastases or other relevant alterations were observed. The CA125 level was 10 U/mL. Using the IOTA ADNEX model, the determined risk of malignancy was 8.2%. The patient underwent an uneventful robotic hysterectomy with bilateral adnexectomy. Histopathological evaluation found that the solid neoplasm with cystic spaces was composed of mature tissues derived from ectoderm (skin and nervous tissue), mesoderm (adipose tissue, smooth muscle tissue and cartilage) and endoderm (gastrointestinal epithelium, salivary and thyroid. glandular tissues). Furthermore, a component of thyroid tissue with areas of follicular hyperplasia was identified, in which a 2.4mm papillary thyroid microcarcinoma was documented. To our knowledge, malignant transformation of a mature ovarian teratoma is a rare condition usually consisting of squamous cell carcinoma. This communication provided the ultrasound features of such a lesion with malignant degeneration of the thyroid tissue component. Studying and reporting additional cases would be beneficial to better understand the pathogenesis, natural history, clinical and imaging aspects of the disease. 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.