Follicular Thyroid Carcinoma Metastatic to the Kidney: Report of a Case with Cytohistologic Correlation

Abstract

Here we report a case of a 45-year-old female who underwent thyroidectomy for thyroid cancer and presented 20 years later with a left renal mass. CT-guided core biopsy was performed, and imprints and histologic sections of the biopsy showed cells resembling thyroid follicular cells with a background containing colloid. Immunohistochemistry revealed positivity for thyroglobulin and thyroid transcription factor 1, consistent with metastatic follicular thyroid carcinoma (FTC). The patient later underwent radical nephrectomy; histologic sections of the resected tumor revealed an encapsulated lesion morphologically similar to the biopsy specimen. Thyroid metastases to the kidney are extremely rare and are often detected during postthyroidectomy surveillance by elevation in thyroid hormone levels, 131I scintigraphy, or 18F-fluorodeoxyglucose uptake in positron emission tomography studies. Treatment involves total thyroidectomy, resection of the metastatic foci, and 131I therapy. The differential diagnoses of renal metastasis of FTC include the encapsulated follicular variant of papillary thyroid carcinoma (PTC), which possesses some of the nuclear features seen in conventional PTC but may occasionally be indistinguishable from FTC in cytologic preparations, and renal lesions such as benign thyroidization of the kidney and thyroid-like follicular carcinoma of the kidney, which mimic FTC in histologic appearance but do not stain with thyroid markers.

Thyroid-like follicular carcinoma of the kidney: A Case report

“…Primary thyroid-like follicular carcinoma of the kidney(TLFCK) is a least-frequent and least-studied variant of renal tumor, named purely from the light microscopic appearance, with well-circumscribed pseudocapsules resembling to thyroid follicular carcinoma microscopically but negative for the thyroid-specific markers [2,3,15]. In all reported cases, there were no significant distinguish from other types of renal tumor on location and clinical performance.…”

“…TLFCK is a kind rare pathological type of renal tumor, which is potentially considered origining in the renal parenchymal urinary tubule epithelial system [1]. This unique histopathological type of RCC(renal cell carcinoma), described firstly in 1996 by Angell et al, had not been recorded in the 2004 world health organization in account of the lack of sufficient clinical evidence that only 28 cases reported in the English literature to date [2][3][4][5][6][7][8][9][10][11][12][13][14][15]. TLFCK has a similar feature with the follicular carcinoma of the thyroid in morphology.…”

Thyroid-Like Follicular Carcinoma of the Kidney in a Patient with Skull and Meningeal Metastasis

“…Although they are very rare, metastases to the kidney from the thyroid have been reported. 27 To our knowledge, 21 cases have been reported in the English-language literature and another 30 in the Japanese literature. 27 Of the 21 cases of renal metastasis associated with differentiated thyroid carcinoma (DTC), 9 were from papillary carcinoma (6 were follicular-variant papillary carcinomas) and 12 were from follicular carcinoma.…”

“… 27 To our knowledge, 21 cases have been reported in the English-language literature and another 30 in the Japanese literature. 27 Of the 21 cases of renal metastasis associated with differentiated thyroid carcinoma (DTC), 9 were from papillary carcinoma (6 were follicular-variant papillary carcinomas) and 12 were from follicular carcinoma. 28 TLFCK usually presents as a solitary tumor, but the majority of thyroid carcinoma metastases to the kidney are widely disseminated.…”

Nephrectomy for Metastatic Kidney Tumor in Patients with Differentiated Thyroid Cancer: A Report of Two Cases

“…Thus, to date, effective treatment methods for renal metastasis from thyroid cancer remain unavailable. When a tumor is metastasized to the kidneys, it generally comprises other metastatic lesions or is bilateral [ 2 ]. Herein, we report cases of two patients with DTC who underwent nephrectomy for a metastatic kidney tumor.…”