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The Korean Journal of Pathology 2007;41(6): 412-415.
Metastatic Medullary Carcinoma of Thyroid to Breast; A Case Initially Diagnosed as Primary Invasive Lobular Carcinoma: A Case Report.
Youngseok Lee, Jungsuk An, Chul Hwan Kim, Bom Woo Yeom, Jong Sang Choi, Yang Seok Chae
Department of Pathology, Korea University Anam Hospital, Seoul, Korea. yschae21@korea.ac.kr
Metastasis to the breast from medullary carcinoma of the thyroid is extremely rare. We report a case of metastatic medullary carcinoma of the thyroid which presented as multiple breast masses with ipsilateral axillary lymphadenopathy in a 48-year-old woman. Six years ago, she underwent total thyroidectomy and neck dissection because of palpable neck masses, with a diagnosis of medullary thyroid carcinoma. Histological features of breast masses showed single- file or linear-cord arrangements, with plasmacytoid appearance, and the initial diagnosis was invasive lobular carcinoma. She underwent modified radical mastectomy. The tumor cells were diffusely positive for E-cadherin, calcitonin and thyroid transcription factor-1 (TTF-1) and were metastatic medullary carcinoma of thyroid. In the patients with a history of medullary carcinoma of the thyroid, a careful examination is necessary for a breast mass composed of solid and cord-like clusters of small round to ovoid cells with plasmacytoid appearance. Immunohistochemical staining for E-cadherin, calcitonin and TTF-1 could be helpful for differential diagnosis.
Key Words: Medullary carcinoma; Thyroid; Breast; Metastasis; Invasive lobular carcinoma