# Case Report: A rare case of chest wall thyroid carcinosarcoma

## TL;DR

A 66-year-old woman developed a rare chest wall thyroid carcinosarcoma after prior thyroid cancer and radioactive iodine treatment.

## Contribution

This case report highlights a rare occurrence of thyroid carcinosarcoma in the chest wall following prior radioactive iodine therapy.

## Key findings

- The patient had a history of papillary thyroid carcinoma and received radioactive iodine therapy.
- A surgically resected chest wall mass was confirmed as thyroid carcinosarcoma.
- The report explores the possible link between prior RAI therapy and the development of TCS.

## Abstract

Thyroid carcinosarcoma (TCS) is a rare and aggressive malignant tumor, typically reported as a primary thyroid neoplasm. Here, we present an unusual case of TCS occurring in the chest wall. The patient was a 66-year-old woman with a history of papillary thyroid carcinoma (PTC) diagnosed 12 years prior. She received two courses of radioactive iodine (RAI) therapy (200 mCi and 150 mCi) five years ago for metastatic disease in cervical lymph nodes and lungs. Four years after completing RAI treatment, she presented with a progressively enlarging left chest wall mass, which was surgically resected and pathologically confirmed as TCS. This report details the patient’s clinical course and explores the temporal and topographic association between the development of TCS and the prior RAI therapy.