Tumor-to-tumor Metastases to Follicular Variant of Papillary Thyroid Carcinoma: Histologic, Immunohistochemical, and Molecular Studies of Two Unusual Cases

Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA.
Endocrine Pathology (Impact Factor: 1.76). 09/2009; 20(4):235-42. DOI: 10.1007/s12022-009-9087-x
Source: PubMed


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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    • "Common sites of primary tumors that can metastasize to the thyroid gland are lung, breast, kidney, and head and neck [1]. Tumor-to-tumor metastases, in which a thyroid neoplasm is the recipient of a metastasis, are extremely rare [2]; to the best of our knowledge, only nine cases of renal cell carcinoma metastasis to thyroid tumor have been previously reported in the literature (Table  1) [3-7]. "
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    ABSTRACT: Metastatic neoplasms to the thyroid gland are rare in clinical practice. Clear cell renal carcinoma is the most frequent site of origin of thyroid metastases and represents 12 to 34% of all secondary thyroid tumors. Tumor-to-tumor metastases, in which a thyroid neoplasm is the recipient of a metastasis, are exceedingly rare. We report a case of clear cell renal carcinoma metastatic to a follicular adenoma. This is the tenth case of renal cell carcinoma metastasis to thyroid tumor reported in the literature. A 62-year-old Caucasian woman with a history of clear cell renal carcinoma was admitted to our institution for multinodular goiter. A histological examination after total thyroidectomy revealed clear cell renal carcinoma metastasis to a thyroid follicular adenoma. Preoperative diagnosis of secondary thyroid neoplasm is difficult to achieve. The diagnosis of metastatic disease should be taken into account if patients have a history of clear cell renal carcinoma or if there is a multifocal growth pattern and clear cell appearance of the cytoplasm.
    Journal of Medical Case Reports 12/2013; 7(1):265. DOI:10.1186/1752-1947-7-265
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    • "In rare instances, tumor-in-tumor phenomena reflect tumorto-tumor metastases, mainly to follicular adenoma or to follicular variant of papillary thyroid carcinoma [14]. Primary papillary thyroid carcinoma can also grow in the core of a follicular adenoma exhibiting a tumor-in-tumor pattern [16]. "
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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.
    Case Reports in Oncological Medicine 04/2013; 2013:485025. DOI:10.1155/2013/485025
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    • "Presence of Ras mutation favors a primary thyroid follicular neoplasm over metastatic renal cell carcinoma. Loss of VHL gene locus favors a diagnosis of metastatic renal cell carcinoma over a primary thyroid neoplasm with clear cell change [22]. This paper reviews the 27 reported cases of a thyroid neoplasm serving as recipient in a tumor-to-tumor metastasis and describes the 28th such case, a poorly differentiated carcinoma of lung metastatic to a follicular adenoma. "
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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.
    Pathology Research International 03/2011; 2011(1):238693. DOI:10.4061/2011/238693
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