Isolated metastasis of malignant melanoma into follicular carcinoma of the thyroid gland

Abstract

A 38-yr-old woman with a history of malignant melanoma (MM) presented with a thyroidal nodule. Fine needle aspiration biopsy of the thyroid was consistent with metastatic MM. The patient underwent thyroidectomy: microscopic examination revealed a follicular carcinoma nodule harboring a focus of metastatic melanoma. On review of the fine needle aspiration biopsy specimen, the population of cells with more uniform nuclei with focal follicle formation, which initially was interpreted as cells originating from normal thyroid tissue, was seen to actually represent the follicular carcinoma component. Tumor-to-tumor metastasis is an interesting phenomenon and there are only few cases of MM metastasis to other tumors. MM metastasis into a neoplastic thyroid nodule is a very rare combination and may be explained because the nodule in question represents the most highly vascularized component of the thyroid.

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

“…The most frequently reported recipient tumor is renal cell carcinoma (RCC, 40-70%), followed by sarcoma, meningioma, thyroid neoplasm, and pituitary adenoma [1,2]. In the English literature, there are only 19 cases of tumor-totumor metastases involving recipient thyroid neoplasms [1,[3][4][5][6][7][8][9][10][11][12][13][14][15]. We present two diagnostically challenging cases of tumor-to-tumor metastases that were resolved by integrating clinical, morphologic, immunohistochemical, and molecular findings.…”

Metastasis of Colon Cancer to Medullary Thyroid Carcinoma: A Case Report

“…Fourteen cases of metastatic tumor to the primary thyroid carcinoma have been reported previously in the literature. The majority of reported primary thyroid carcinomas were papillary thyroid carcinoma (PTC), including follicular variant papillary thyroid carcinoma (FVPTC) (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11). To our knowledge, there has been no reported case of a tumor metastasizing to medullary thyroid carcinoma (MTC).…”

Tumors Metastatic to Thyroid Neoplasms: A Case Report and Review of the Literature

“…In all cases an abrupt transition to a morphologically distinct neoplasm was noted. Of these 28 cases, the recipient thyroid neoplasm was benign in 16 cases (follicular adenoma) ([4–8, 10–12, 15, 17–19, 23],and the present case) and malignant in 12 cases [3, 4, 9, 13, 14, 16, 20–22]. Of the 12 malignant recipient thyroid neoplasms, there were 9 papillary carcinomas [3, 4, 9, 20–22] (6 of which were follicular variants of papillary carcinoma [9, 21, 22]) and 3 follicular carcinomas [13, 14, 16] (2 of Hurthle cell type [13, 14]).…”

“…Of these 28 cases, the recipient thyroid neoplasm was benign in 16 cases (follicular adenoma) ([4–8, 10–12, 15, 17–19, 23],and the present case) and malignant in 12 cases [3, 4, 9, 13, 14, 16, 20–22]. Of the 12 malignant recipient thyroid neoplasms, there were 9 papillary carcinomas [3, 4, 9, 20–22] (6 of which were follicular variants of papillary carcinoma [9, 21, 22]) and 3 follicular carcinomas [13, 14, 16] (2 of Hurthle cell type [13, 14]). Renal cell carcinoma was the most common donor neoplasm metastasizing to a primary thyroid neoplasm (9 cases) [3–5, 9, 12, 13, 15, 17, 22] followed by lung carcinoma (6 cases, including the present case) [6, 8–10, 20], breast carcinoma (5 cases, including one infiltrating lobular carcinoma) [4, 7, 18, 21, 22], and colon carcinoma (3 cases) [10, 14, 19].…”