ECE2024 Eposter Presentations Endocrine-Related Cancer (90 abstracts)
1Centro Hospitalar e Universitário de Coimbra, Serviço de Endocrinologia, Diabetes e Metabolismo, Coimbra, Portugal; 2Centro Hospitalar e Universitário de Coimbra, Serviço de Cirurgia Geral, Coimbra, Portugal; 3Centro Hospitalar e Universitário de Coimbra, Serviço de Urologia, Coimbra, Portugal
Introduction: Metastasis to the thyroid gland is a rare phenomenon and is associated with primary tumors of the kidney, lung, breast, colorectal, and sarcoma. Thyroid metastases account for only 0.4-3.0% of all malignant neoplasms of the thyroid and occur more frequently in patients with goiter, thyroiditis, or nodules than in patients without previous thyroid pathology.
Case report: A 57-year-old woman with a history of clear cell renal cell carcinoma (CCRCC) underwent right radical nephrectomy in 08/2020. During follow-up, on 11/2020, a heterogeneous nodule was detected in the thyroid isthmus measuring 32 mm and extending to the anterior mediastinum (CT scan). Thyroid ultrasound described an 11 mm nodule in the isthmus, and fine-needle aspiration cytology yielded a benign colloid result. In 07/2022, an abdominal CT scan revealed a heterogeneous mass in the right adrenal gland measuring 58mm, prompting referral to Endocrinology. Hormonal studies were negative. Preoperative staging CT scan described the adrenal and retrosternal mediastinal mass of thyroid origin measuring 38mm. Thyroid ultrasound reported a "nodule at the lower pole of the left lobe-isthmus transition, partially submerged, hypoechoic, heterogeneous, solid, with regular borders, doubtful microcalcifications, and measuring 24×20×39mm." Fine-needle aspiration cytology indicated a suspicious result for papillary thyroid carcinoma (Bethesda V). A two-stage surgery was scheduled: first, she underwent right adrenalectomy, whose histopathological examination identified a CCRCC metastasis in the adrenal gland; subsequently, total thyroidectomy was performed, revealing not a primary thyroid neoplasm but a thyroid metastasis from CCRCC and a small follicular adenoma in the isthmus. The patient continued follow-up in Urology and is currently on sunitinib after the emergence of a neoplastic lesion in the left kidney and suspicious subcentimeter lung nodules.
Conclusion: Although thyroid metastases are uncommon, it is important to consider this possibility in patients with thyroid nodules and a history of malignancy. Fine-needle aspiration cytology has a sensitivity of approximately 70-80% in diagnosing metastatic nodules, but the differential diagnosis can still be challenging and established only after histopathological examination. The relevance of this case is also justified by the rarity of metastasis from CCRCC to two endocrine glands - thyroid and adrenal.