Metastatic Clear Cell Renal Cell Carcinoma Involving the Thyroid Gland: A Clinicopathologic Study of 17 Patients

Abstract

Context. Metastatic clear cell renal cell carcinoma (RCC) is one of the most common secondary thyroid malignancies. Diagnosis can be challenging, particularly if presenting many years after initial diagnosis. We reviewed clinicopathologic features and immunoprofile of metastatic clear cell RCC in thyroid. Design. We identified 17 patients from 2003-2021. Clinical data were obtained from medical records, and slides were retrieved and reviewed. Results. Seventeen patients (12 male and 5 female) included 12 thyroidectomies, 3 core biopsies, 1 excisional biopsy, and 1 fine-needle aspiration. The average patient age was 68.7 years (range, 45-88 years). Sixteen patients had history of clear cell RCC, and in 1 patient, the clear cell RCC was discovered after the thyroid metastasis was found. Thyroid gland metastases were on average diagnosed 90.7 months after the diagnosis of the renal primary (range, 24-240 months). Patients presented with a new palpable mass (n = 11) or dyspnea/stridor (n = 1). Five tumors were incidentally found via surveillance imaging. In 2 patients, metastases occurred within follicular thyroid neoplasms. All metastases showed conspicuous sinusoidal vasculature between the tumor nests and areas of myxoid degeneration. A prominent thick fibromuscular pseudocapsule was evident in 10 resections. Immunohistochemistry (n = 5) showed that the metastases were positive for PAX8, CA9, and CD10, while negative for keratin 7, thyroglobulin, and TTF1. Conclusions. Metastatic clear cell RCC involving the thyroid gland is infrequent and typically occurs remotely after the initial diagnosis. Cytologic and histologic features may show significant overlap with primary thyroid lesions. Immunohistochemistry can help reliably distinguish metastases from primary thyroid neoplasms.

Fine‐needle aspiration diagnosis of secondary malignant tumors of the thyroid gland: A single‐institution experience of 17 cases

“…[17][18][19][22][23][24][25] The male-to-female ratio was 1:1.2, 18 This is the largest similar series reported in recent years. In contrast to previous studies, renal clear cell carcinoma with metastasis to the thyroid gland, which has been reported more frequently before, 4,8,17,23,25 was not found in our study, and it also did not include any sarcoma, which may be a bias caused by our sample size.…”

“…Secondary malignancies of thyroid gland (SMTG) are uncommon, with an incidence of 1.25%–24% in autopsy series, 2 and 1.4%–3% in all patients operated on for thyroid malignancies 3 . Secondary tumors most commonly involving the thyroid gland include tumors of the pharynx, larynx, esophagus, and mediastinum, and sources of distant metastatic tumors, include the kidney, lung, breast, and gastrointestinal tract 4–10 …”

“…3 Secondary tumors most commonly involving the thyroid gland include tumors of the pharynx, larynx, esophagus, and mediastinum, and sources of distant metastatic tumors, include the kidney, lung, breast, and gastrointestinal tract. [4][5][6][7][8][9][10] In rare cases, metastases in the thyroid may be the primary clinical manifestation of distant malignancy. Therefore, correct identification of these secondary tumors in samples from FNA of thyroid nodules is important to avoid unnecessary surgical resection in patients who have extensive metastases.…”

Tumor-to-Tumor Spread: A Case Report and Literature Review of Renal Cell Carcinoma Metastasis into Thyroid Cancer

“…Thus, a panel of stains must be used to guide the diagnosis. It has been suggested that positivity for CAIX, PAX-8 and negativity for TTF-1, TG and keratin 7 are supportive of metastatic RCC when found in the thyroid gland (19). Our patient's staining pattern was PAX-8(+)/TG(-)/TTF-1(-) supported RCC as the origin of the specimen.…”

Clinical, cytological, and pathological characteristics of metastatic renal cell carcinoma to the thyroid: A study of 14 cases at a Japanese single institution

“…TTM is extremely rare. However, TTM in MRCCT is not a rare phenomenon and can occur in thyroid neoplasms, such as follicular adenoma, follicular variant of papillary thyroid carcinoma, and noninvasive follicular thyroid neoplasm with papillary‐like nuclear features 8,10,20–23 . Heffess et al reported that 27.8% of MRCCT metastasized into adenomatous nodules or follicular adenoma 10 .…”