Thyroid metastasis of clear renal cell carcinoma: a case report and review of the literature

Abstract

The thyroid is a rare site for finding tumor metastases. Renal, colorectal, pulmonary, and mammary origin are the most frequent primary neoplasms. Clinical suspicion, early diagnosis, and active surveillance are important during follow-up. Thyroid ultrasound and fine needle aspiration thyroid ultrasound are crucial during follow-up. We present a case of a 66-year-old male who was referred to our Endocrinology and Nutrition Department of the Hospital General Universitario Santa Lucía due to a multinodular goiter. The patient had no symptoms of hyperthyroidism or hypothyroidism. No weight loss or constitutional syndrome was reported. The patient was suffering from a renal clear cell carcinoma with T3aNxM0 stage operated on using a nephrectomy technique in 2012. In a new follow-up, a positron emission tomography-computed tomography (PET-CT) scan was conducted and a multinodular goiter was found with an increase in size and metabolism at the expense of a right thyroid nodule and thyroid ultrasound and fine needle aspiration thyroid ultrasound was requested with the diagnosis of renal cell carcinoma metastasis. We present a rare case report since both metastases (thyroid and pulmonary) could be surgically intervened with curative intent and a review of the literature. This case emphasizes the importance of considering a metastatic origin when finding a thyroid nodule in a patient with a previous history of clear renal cell carcinoma even years after treatment with curative intent.

Keywords: Clinical endocrinology; case report; clear renal cell carcinoma; thyroid nodule.

Figure 1

patient's chronological evolution

Figure 2

thyroid ultrasound: hypoechogenic, ovoid, solid thyroid nodule with well-defined margins

Figure 3

hematoxylin-eosin image of the thyroid lesion: A) a neoplastic lesion well delimited by fibrous connective tissue that is adjacent to thyroid parenchyma with medium-small follicles covered by a layer of cells without colloid atypia inside; B) the lesion is composed of a neoplastic population of cells with broad whitish cytoplasmic with rounded central nuclei, with small nucleoli, there is no evidence of irregularities or cellular atypia, the cells are surrounded by thin fibrovascular septa that partially compartmentalize the lesion

Figure 4

immunohistochemistry techniques: A) CD10 marker; the image shows intense positivity for the membrane marker CD10 in all tumor cellularity, compatible with the renal origin; B) PAX8 marker; the image shows intense nuclear positivity for the PAX8 marker, this staining is compatible with a renal origin, among other origins