Case reportColon cancer metastasis to the thyroid gland: A case report

- Colorectal metastases to thyroid are rare.
- The majority of the cases of colorectal thyroid metastases are diagnosed lately in the evolution of a known malignancy.
- A low threshold of suspicion is crucial to make a timely diagnosis in order to avoid its high morbidity.
- Colorectal thyroid metastization could be clinically silent and a raise in tumoral markers could be the only sign.
- Treatment is controversial and the prognosis is usually poor. Without surgery, the need may arise for tracheostomy.

IntroductionThyroid metastases from colorectal cancer are uncommon and few cases are described in literature.Case presentationA 64-year-old female patient presented with an asymptomatic right cervical nodule with a rapid growth six years after sigmoidectomy for cancer and two years after resection of colorectal lung metastases. Increased CA 19.9 was identified and a thoracoabdominal CT scan revealed the onset of new metastatic bilateral pulmonary lesions. Neck ultrasonography showed a suspicious nodule in the right thyroid lobe, and Fine-needle Aspiration Cytology (FNAC) of the nodule lead to the diagnosis of colorectal cancer metastasis. A right thyroid lobectomy with right central lymph node dissection was performed. The patient underwent chemotherapy with response, but this was posteriorly suspended due to haematological side effects, and the disease spread.DiscussionThyroid metastases from colorectal cancer are rare, but, with the improvement of radiologic exams and the higher survival rate of these patients, more cases are being described. The majority of the cases present pulmonary and hepatic metastases and the prognosis is poor. The decision to operate and the type of operation depend on the extent of the metastatic disease and the patient's overall condition.ConclusionA low threshold of suspicion is crucial to make a timely diagnosis of thyroid metastases from colorectal cancer. Treatment is controversial, but, without surgery, the need may arise for tracheostomy.