Clinicopathological study of clear-cell tumors of the thyroid: An evaluation of 22 cases

Abstract

Twenty-two cases of partial or wholly composed clear-cell thyroid tumors were reviewed to differentiate between a primary nodule and metastatic clear-cell renal carcinoma in the thyroid. Pathological reevaluation of HE-stained specimens, immunohistochemical observation using anti-thyroglobulin (TG) antibody, and periodic acid-Schiff (PAS) staining were performed. The pathological characteristics in metastases from the kidney have a greater tendency to demonstrate a strikingly clear cytoplasm with small nuclei, rich vascularization, and a trabecular arrangement of tumor cells than do primary thyroid cases. The immunohistochemical TG staining in conjunction with PAS staining for the recognition of follicular colloid could provide much more reliable information of primary cases compared to that using TG staining alone. Clinically, in primary cases, the female:male ratio is substantially higher while the mean age is lower than in metastatic cases reflecting differentiated thyroid carcinoma. In conclusion, immunohistochemical staining for TG with PAS staining for the recognition of follicular colloid proved to be the most sensitive method for identifying primary clear cell thyroid tumors. In addition, a careful assessment of past and/or present kidney disorders to rule out metastatic renal cell carcinoma is advisable. Age, gender, and physiological findings are also informative when differentiating between them.

Solitary Metachronous Metastasis to the Thyroid from Renal Clear Cell Carcinoma 19 Years After Nephrectomy: Report of a Case

“…1-3 Although RCC is another malignant source for thyroid metastasis, 1-5 it is rarely encountered in clinical practice. [6][7][8] Thyroid metastases from RCC are occasionally found years after a primary nephrectomy, but this is exceedingly rare in a patient with a remote history of more than 15 years. Table 1 summarizes the reported cases of thyroid metastases from RCC in patients with a remote history (Ͼ15 years), including the time from diagnosis of the primary carcioma until metastases were found in the thyroid.…”

“…[1][2][3] Although renal cell carcinomas (RCCs) have been considered as another cancer that can potentially metastasize to the thyroid, [1][2][3][4][5] this rarely occurs in clinical practice. [6][7][8] A solitary late RCC metastasis to the thyroid is especially rare, with very few reports published in the showing relatively rapid growth over a few months. Fine-needle aspiration performed at another hospital suggested that the tumor might be poorly differentiated or undifferentiated thyroid carcinoma.…”

“…22 Subsequent immunohistochemical staining with thyroglobulin (Tg) is helpful for distinguishing between primary and metastatic thyroid carcinomas. 7,9,13,15,18,22 We used both Tg and thyroid transcription factor-1 (TTF-1) stains to confirm the RCC metastasis. TTF-1, a homeodomain containing the nuclear protein originally identified in thyroid follicular cells, has been evaluated as an immunohistochemical marker for the identification of thyroid or lung tissue.…”

Solitary Thyroid Metastasis of Renal Clear Cell Carcinoma: Report of a Case

“…However, it may be histologically difficult to distinguish such lesions from primary clear cell thyroid tumors by routine hematoxylin-eosin staining. Thyroglobulin immunohistochemical staining is considered to be the best method of the two; 18 and such staining should be negative in metastatic thyroid clear cell carcinoma, whereas it should be positive in primary clear cell thyroid tumors. Preoperative fine-needle aspiration cytology has recently been described to be an effective procedure for the diagnosis of metastatic thyroid cancer.…”

Fine Needle Aspiration Cytology of Follicular Carcinoma with Clear Cell Change

“…Several small series on clear cell change in thyroid tumors have been published. [1][2][3][4][5] The fine needle aspiration and crush preparation cytology has rarely been described. [6][7][8][9][10][11] We report the cytologic findings in a case of minimally invasive follicular carcinoma undergoing marked intracellular accumulation of lipid and mucin, with subsequent histologic correlation.…”