Case report

Metastatic colorectal cancer to a primary thyroid cancer

Martin H Cherk¹ , Maggie Moore² , Jonathan Serpell³ , Sarah Swain⁴ and Duncan J Topliss⁵

¹  Department of Nuclear Medicine, the Alfred Hospital, Commercial Road, Melbourne Victoria 3004, Australia

²  Department of Medical Oncology, the Alfred Hospital, Commercial Road, Melbourne Victoria 3004, Australia

³  Department of Surgery, the Alfred Hospital, Commercial Road, Melbourne Victoria 3004, Australia

⁴  Department of Anatomical Pathology, the Alfred Hospital, Commercial Road, Melbourne Victoria 3004, Australia

⁵  Department of Endocrinology and Diabetes, the Alfred Hospital, Commercial Road, Melbourne Victoria 3004, Australia

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World Journal of Surgical Oncology 2008, 6:122doi:10.1186/1477-7819-6-122

Published:	11 November 2008

Abstract

Background

Metastatic malignancy to the thyroid gland is generally uncommon due to an unfavourable local thyroid micro-environment which impairs the ability of metastatic cells to settle and thrive. Metastases to the thyroid gland have however been reported to occur occasionally particularly if there has been disruption to normal thyroid tissue architecture.

Case presentation

We report a patient with a history of surgically resected rectal adenocarcinoma who presents with a rising serum CEA level and an ¹⁸F-FDG PET scan positive thyroid nodule which was subsequently confirmed at surgery to be a focus of metastatic rectal adenocarcinoma within a primary poorly differentiated papillary thyroid carcinoma.

Subsequent treatment involved right hemi-thyroidectomy, pulmonary wedge resection of oligometastatic metastatic colorectal cancer and chemotherapy.

Conclusion

Metastatic rectal carcinoma to the thyroid gland and in particular to a primary thyroid malignancy is rare and unusual. Prognosis is likely to be more dependent on underlying metastatic disease rather than the primary thyroid malignancy hence primary treatments should be tailored towards treating and controlling metastatic disease and less emphasis placed on the primary thyroid malignancy.