Colorectal cancer metastases in thyroid: case report and literature review

Abstract

Background The thyroid gland is an uncommon site for metastatic deposits from non-thyroid malignancies, occurring in only 1.4 - 3% of surgical specimens where malignancy is suspected. It is even rarer for the source of thyroid metastases to be of colorectal origin. In most cases reported, colorectal metastases in the thyroid occurs many years later after the primary colorectal cancer has been diagnosed and treated. In this unique case, a primary sigmoid carcinoma metastasised to the thyroid gland and presented synchronously as a thyroid nodule. Case presentation We describe a case of a 64-year-old Caucasian woman who presented with clinical features of metastatic cancer of unknown origin. Her medical history included underlying hyperthyroidism. She had a large pelvic mass adjacent to the sigmoid colon, a left lower lobe lung mass and a suspicious nodule in the left thyroid lobe. A fine-needle aspiration biopsy of the thyroid nodule was performed, which remarkably showed malignant cells originating from primary colorectal cancer on immunohistochemical staining. The patient was managed with palliative chemotherapy given the poor prognosis due to disseminated colorectal malignancy. Conclusions Colorectal adenocarcinoma metastases can rarely present as a metastatic thyroid nodule. Fine-needle aspiration should be performed in suspicious thyroid nodules and may be the least invasive way of identifying a metastatic colorectal or other non-thyroidal malignancy in patients presenting with an unknown primary. The pathologist should be vigilant to this possibility and specific immunohistochemical markers should be used to ensure accurate diagnosis. In thyroid metastases, the prognosis is ultimately determined by the primary tumour but thyroidectomy still has a role in alleviating compressive symptoms and can potentially improve survival in selected cases.

A Rare Case of Thyroid Metastasis From Colorectal Cancer: Diagnostic and Therapeutic Challenges

“…After all, the diagnostic accuracy seems to be affected by the type of malignancy. Metastatic adenocarcinomas of breast, lung, and colorectal origin are often correctly diagnosed, whereas metastatic squamous cell carcinomas of oesophageal and cervical origin can be challenging to diagnose [6]. FNA accurately diagnosed colorectal cancer thyroid metastases in our case.…”

“…A literature review of metachronous colon metastases to the thyroid gland by Froylich et al identified only 34 cases from 1931 to 2013 originating from the following sites: rectum (41%), sigmoid colon (33%), ascending colon (19%), and descending colon (11%) [9]; since the review in 2013, Hussein et al reported 14 cases describing thyroid metastases of colorectal origin [6]. What is more, in a comprehensive systematic review by Manatakis et al, 111 patients were identified to have colorectal thyroid metastasis [5].…”

“…Additionally, the relatively short overall survival of patients with advanced malignancies restrains the assessment of newly detected thyroid metastases. To date, less than 120 cases of metastatic colorectal adenocarcinomas of the thyroid gland have been reported [5,6]. Herein, the case of a patient with colon cancer that metastasized to the thyroid gland is presented.…”

Colorectal cancer metastasis to the thyroid: A case report and review of the literature

“…Clinically, metastatic malignant tumors of the thyroid are relatively rare ( 8 ), accounting for only 1.4–3.0% of all malignant thyroid tumors ( 9 , 10 ). However, the proportion of metastatic malignant tumors found in autopsy results is as high as 9.5% ( 11 ).…”