Tumor-to-tumor metastases to follicular variant of papillary thyroid carcinoma: histologic, immunohistochemical, and molecular studies of two unusual cases.
ABSTRACT Tumor-to-tumor metastasis in thyroid neoplasms is exceedingly uncommon. Two unusual cases of breast carcinoma and renal cell carcinoma metastatic to follicular variant papillary carcinoma are reported. On histologic sections, the donor tumor cells infiltrated the substance of the recipient tumor and the angiolymphatic channels, but the bulk of metastatic tumor was confined within the thyroid carcinoma. Immunohistochemical stains as well as molecular studies confirmed the origin of both donor tumors, as well as the diagnosis of follicular variant of papillary carcinoma in the recipient tumors. Distinguishing between two such tumor populations may be difficult when the donor tumor cells morphologically resemble primary neoplasms of the recipient organ. A history of previous malignancy and ancillary studies can be helpful in making this distinction and rendering the correct diagnosis. A brief review of literature and discussion of tumor-to-tumor metastasis in thyroid neoplasms is also presented.
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ABSTRACT: Clear cell renal cell carcinoma (CCRCC) is the most common origin for metastasis in the thyroid. A 51-year-old woman was referred to our hospital for a subcarinal lesion. Ten years before, the patient had undergone a nephrectomy for CCRCC. Whole-body fluorodeoxyglucose positron emission tomography revealed elevated values in the thyroid gland, while the mediastinum was normal. An endoscopic ultrasonography-guided fine-needle aspiration biopsy of the mediastinal mass was consistent with CCRCC, and this was confirmed after resection. The thyroidectomy specimen also revealed lymphocytic thyroiditis, nodular hyperplasia, one follicular adenoma, two papillary microcarcinomas, and six foci of metastatic CCRCC involving both thyroid lobes. Curiously two of the six metastatic foci were located inside two adenomatoid nodules (tumor-in-tumor). The metastatic cells were positive for cytokeratins, CD10, epidermal growth factor receptor, and vascular endothelial growth factor receptor 2. No BRAF gene mutations were found in any of the primary and metastatic lesions. The patient was treated with sunitinib and finally died due to CCRCC distant metastases 6 years after the thyroidectomy. In CCRCC patients, a particularly prolonged survival rate may be achieved with the appropriate therapy, in contrast to the ominous prognosis typically found in patients with thyroid metastases from other origins.04/2013; 2013:485025. DOI:10.1155/2013/485025
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ABSTRACT: Metastasis into a thyroid neoplasm-tumor-to-tumor metastasis-is exceedingly rare. We describe the 28th documented case of a tumor metastatic to a thyroid neoplasm and review the literature on tumor-to-tumor metastasis involving a thyroid neoplasm as recipient. All cases showed a recipient thyroid neoplasm with an abrupt transition to a morphologically distinct neoplasm. Metastasis into primary thyroid neoplasm was synchronous in 33% of cases and metachronous in 67%. Follicular adenoma was the most common recipient thyroid neoplasm overall (16/28), and papillary thyroid carcinoma was the most common malignant recipient neoplasm (9/28). Of the 9 recipient papillary carcinomas, 6 were follicular variants. Renal cell carcinoma was the most common neoplasm to metastasize to a primary thyroid neoplasm (9/28), followed by lung (6/28), breast (5/28), and colon (3/28) carcinoma. Tumor-to-tumor metastasis should be considered whenever a dimorphic pattern is encountered in a thyroid tumor.03/2011; 2011:238693. DOI:10.4061/2011/238693
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ABSTRACT: This study describes an encapsulated thyroid tumor having 3 different concentric appearances in a 70-year-old man. The most peripheral neoplasm showed features of a microfollicular adenoma; the intermediate lesion displayed typical features of the follicular variant of papillary thyroid carcinoma (FVPTC); and the main, central neoplasm, showed a basaloid configuration. At variance with the other neoplasms, the latter component exhibited high mitotic activity. Necrosis, angio-invasion, or capsular invasions were not observed. The centrally located neoplasm was immunoreactive for several cytokeratins, p63, carcinoembryonic antigen, and galectin-3, and negative for thyroid transcription factor 1, thyroglobulin, calcitonin, CD5, and CK20, featuring a phenotype similar to that of thyroid solid cell nests. A N-RAS mutation was found both in the basaloid and in the FVPTC components. The clinicopathological and immunohistochemical data ruled out the alternative possibilities of intrathyroidal metastasis and tumor from ectopic (thymic, parathyroid, or salivary gland) tissues.International Journal of Surgical Pathology 04/2011; 19(2):276-80. DOI:10.1177/1066896910393506 · 0.96 Impact Factor