Hashimoto's thyroiditis in a benign cystic teratoma of the ovary: case report and literature review

Chemical peritonitis resulting from spontaneous rupture of a mature ovarian cystic teratoma: a case report

Background

Mature cystic teratomas (dermoid cysts) are the most common germ cell tumours with 10-25% incidence of adult and 50% of paediatric ovarian tumours. The aetiology of dermoid cysts is still unclear, although currently the parthenogenic theory is most widely accepted. The tumour is slow-growing and in the majority of cases it is an accidental finding. Presenting symptoms are vague and nonspecific. The main complication of a dermoid cyst is cyst torsion (15%); other reported complications include malignant transformation (1-2%), infection (1%), and rupture (0.3-2%). Prolonged pressure during pregnancy, torsion with infarction, or a direct trauma are the main risk factors for a  spontaneous dermoid rupture that can lead to acute or chronic peritonitis. The diagnosis of mature cystic teratoma is often made in retrospect after surgical resection of an ovarian cyst, because such imaging modalities as ultrasound, computer tomography, or magnetic resonance imaging cannot yet accurately and reliably distinguish between benign and malignant pathology.

Materials and methods

We present a report of a clinical case of a 35-years-old female, who was referred to the hospital due to abdominal pain spreading to her feet for three successive days. She had a history of a normal vaginal delivery one month before. Abdominal examination revealed mild tenderness in the  lower abdomen; no obvious muscle rigidity was noted. Transvaginal ultrasound showed a multiloculated cystic mass measuring 16 × 10 cm in the pelvis. In the absence of urgency, planned surgical treatment was recommended. The next day the patient was referred to the hospital again, with a complaint of stronger abdominal pain (7/10), nausea, and vomiting. This time abdominal examination revealed symptoms of acute peritonitis. The ultrasound scan differed from the previous one. This time, the transvaginal ultrasound scan revealed abnormally changed ovaries bilaterally. There was a large amount of free fluid in the abdominal cavity. The patient was operated on - left laparoscopic cystectomy and right adnexectomy were performed. Postoperative antibacterial treatment, infusion of fluids, painkillers, prophylaxis of the thromboembolism were administered. The patient was discharged from the hospital on the seventh postoperative day and was sent for outpatient observation.

Results and conclusions

Ultrasound is the imaging modality of choice for a dermoid cyst because it is safe, non-invasive, and quick to perform. Leakage or spillage of dermoid cyst contents can cause chemical peritonitis, which is an aseptic inflammatory peritoneal reaction. Once a rupture of an ovarian cystic teratoma is diagnosed, immediate surgical intervention with prompt removal of the spontaneously ruptured ovarian cyst and thorough peritoneal lavage are required.

Coexistence of Papillary Thyroid Cancer and Hashimoto's Thyroiditis Developing within an Ovarian Mature Cystic Teratoma

A wide variety of tissues derived from the three germ layers are seen in ovarian teratomas. Microscopically, the most commonly seen tissues are epidermis, skin adnexa, and neural tissues. Thyroid tissue is present in 10% of ovarian mature cystic teratomas. In this case, report, we present a rare case of papillary microcarcinoma derived in the ovarian teratoma and Hashimoto's thyroiditis with the normal level of serum thyroid hormones, which is normal but positive serum antithyroid peroxidase antibodies.

[Complications of presumed benign ovarian tumors]

The main risk factor of adnexal torsion is a previous adnexal torsion (LE3). There is no clinical, biological or radiological sign that may exclude the diagnosis of adnexal torsion (LE3). The presence of flow at color Doppler imaging does not allow exclusion of the diagnosis (LE2). An emergent laparoscopy is recommended for adnexal untwisting (Grade B), except in postmenopausal women where oophorectomy is recommended (grade C). A persistent black color of the adnexa after untwisting is not an indication for systematic oophorectomy (grade C), since a functional recovery is possible (LE3). Ovariopexy is not routinely recommended following adnexal untwisting (grade C). The clinical signs of intra-cystic hemorrhage and those of rupture of the corpus luteum are not specific (LE4). MRI is not recommended to confirm the diagnosis of intra-cystic hemorrhage (grade C). Malignant transformation of an ovarian cyst is very rare. The presence of a benign ovarian cyst is not associated with an increased risk of ovarian cancer at long-term follow-up (LE2). For these women, an ultrasound follow-up is not recommended (grade C). Dermoid ovarian cyst containing nerve tissue can trigger the production of pathogenic auto-antibody-anti-NMDA, leading to encephalitis. A high proportion of thyroid tissue in a mature teratoma (struma ovarii) may cause hyperthyroidism.