W012

Breast cancer metastases to the thyroid gland – An uncommon sentinel for diffuse metastatic disease

A M Plonczak, A N Di Marco, R Dina, D Gujral, F F Palazzo, Department of Thyroid & Endocrine Surgery, Hammersmith Hospital, Imperial College Healthcare NHS Trust

Aim: To illustrate a rare case of breast metastases to the thyroid gland, present a literature review and discuss its clinical significance

Background: Metastases to the thyroid are rare. The most common cancer to metastasize to the thyroid is the kidney, followed by gastrointestinal tract tumours, lung, skin and only rarely the breast. Outcomes in malignancies metastatic to the thyroid overall are poor. There are no prospective studies addressing the role of surgery in metastatic disease of the thyroid. Isolated thyroidectomy has been proposed as a local disease control option to palliate and prevent the potential morbidity of tumour extension related to the airway.

Case description: A 62 year old female was diagnosed with bilateral carcinoma of the breast in 2004, for which she underwent bilateral mastectomy. The pathology revealed multifocal disease on the right: grade (G)1+ G2 IDC 0/20 lymph nodes (LN) and G1 IDC + DCIS N1 2/18 LN left-sided disease. Surgery was followed by adjuvant chemotherapy and regional radiotherapy. The disease was under control on predominantly hormonal therapy until 2016, when the patient developed cervical lymphadenopathy. The fine needle aspiration (FNA) cytology of the thyroid was reported as papillary thyroid cancer; however, the biopsy of the left lateral nodal disease was more suggestive of breast malignancy. The patient underwent a total thyroidectomy and a clearance of the central compartment lymph nodes. The histopathological analysis was consistent with metastatic breast cancer, with no evidence of a primary thyroid malignancy.

Conclusion & Clinical Significance: In conclusion, a past history of a malignancy elsewhere should raise the index of suspicion of metastatic disease in patients presenting with a thyroid lump with or without cervical lymphadenopathy. If confirmed on FNAB it is usually a poor prognostic sign and indicative of disease beyond cure.  The empirical thyroidectomy can be considered in select patients for local disease control.