Introduction: Metachronic metastasis of renal carcinoma to the thyroid gland, a rare entity occurring sometimes many years after nephrectomy, have been already reported by literature. Thyroidal synchronous metastasis, instead, are more uncommon. We herein report a patient with thyroidal metastasis and intrajugular thrombo embolic involvement as initial presentation of a misunderstood renal carcinoma.
Case Report: A 83-years-old woman, with silent medical history, was referred to our department for toxic multinodular goiter. She presented an enlarged thyroid containing multiple solid nodules in the left lobe, and a single lesion in the right one. A new ultrasound performed two months later confirmed multiple nodules in the left lobe some of which presented ultrasonographic and elastosonographic features suspicious for malignancy, i.e. hypoechogenicity, irregular margins, intralesional vascularization, spot microcalcifications and stiffness; on the contrary, the single nodule in the right lobe was homogeneous and elastic. Nevertheless it was remarkable increased in size, i.e. 47 vs 30 mm, and it partially infiltrated thyroid capsule in its upper third with at least three thrombo-embolic lesions involving omolateral jugular vein.
Therefore, we performed a fine-needle-aspiration on right nodule and cytological examination reported a lesion made of clear cells compatible with metastasis of renal carcinoma. Therefore, a tumour was localized in the right kidney by TC and then confirmed by pathology after laparoscopic robot assisted right radical nephrectomy. Total thyroidectomy was also performed and only the right nodule turned out to be a metastatic lesion at histology, resulting all the others hyperplastic nodules.
Conclusion: Although uncommon, metastatic renal carcinoma to the thyroid gland should be considered even in patients with thyroid nodules not presenting a medical history of renal cell carcinoma. Thyroid metastasis of renal carcinoma might not necessary present ultrasonographic and elastographic characteristics suspicious for malignancy. A careful neck-ultrasound might be decisive in making the correct diagnosis.