# Differentiated and Poorly Differentiated Thyroid Carcinoma in Ovarian Teratoma With Primary Papillary Thyroid Carcinoma: A Series of Two Case Reports

## TL;DR

This paper reports two rare cases of thyroid cancer developing within ovarian teratomas, highlighting the importance of thorough diagnosis and treatment.

## Contribution

The novelty lies in describing two distinct cases of thyroid carcinoma within ovarian teratomas, including a rare concurrent poorly differentiated thyroid cancer.

## Key findings

- Thyroid carcinoma within ovarian teratoma can occur and requires thorough histological evaluation.
- Patients with this condition can achieve favorable outcomes with appropriate surgical and adjuvant treatment.
- A BRAF mutation was identified in one case, suggesting genetic factors may play a role.

## Abstract

Teratoma is a tumor that originates from one or more layers of germ cells. It may contain several types of tissues. Ovarian teratomas are the most common amongst all teratomas. These can be immature, mature, and monodermal. Incidence of thyroid carcinoma originating from ovarian teratoma is rare, but cases have been reported previously.

In this case series, we describe two different cases, both presenting at separate times during their treatment of thyroid carcinoma in ovarian teratoma.

The first patient presented to the gynecological surgery outpatient department with a history of abdominal pain and excessive menstrual bleeding. She underwent hysterectomy and oophorectomy; review of the histopathology of the specimen turned out to be ovarian teratoma with papillary thyroid carcinoma. Further workup revealed that she had a B-Raf proto-oncogene, serine/threonine kinase (BRAF) mutation. After discussing the case in a multidisciplinary team meeting, she underwent treatment for thyroidectomy completion surgery, followed by radioactive iodine therapy. Currently, she is under follow-up with the endocrinology team and disease-free.

Our second patient is an extremely rare case of concurrent presence of poorly differentiated thyroid carcinoma in ovarian teratoma with primary papillary thyroid carcinoma. She presented with thyroid swelling, which gradually increased in size to the point she developed dyspneic symptoms. She underwent total thyroidectomy for symptomatic control, and in her histopathology report, it turned out to be high-risk papillary thyroid carcinoma. She then received radioactive iodine therapy. The post-therapy scan showed uptake in thyroidectomy bed remnant thyroid tissue and intense uptake in adnexa. In the multidisciplinary team meeting, it was decided to remove the adnexal mass. Histopathology revealed poorly differentiated thyroid cancer in ovarian teratoma. She is currently on endocrinology follow-up and disease-free.

This case series highlights the rare occurrence of malignant transformation, specifically thyroid carcinoma within ovarian teratoma, and underscores the importance of thorough histological evaluation in patients with atypical presentations and relevant genetic mutations. These patients showed speedy recovery and are on follow-up with minimal post-treatment complaints, demonstrating a favorable outcome with appropriate surgical and adjuvant management.