Tumor to Tumor Metastasis to Medullary Carcinoma of Thyroid

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 414-428-Thyroid Neoplasia & Case Reports
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-420
Jioh Mok*1, Sungrae Kim2, Chong Hwa Kim3 and Ki-Young Lee4
1Soonchunhyang Univ, Bucheon-Si, South Korea, 2CATHOLIC UNIV of Korea, Puchon, South Korea, 3Sejong General Hospital, Bucheon, South Korea, 4Gachon Univ of Medicine & Scie, Incheon, South Korea
A 55-year old man presented 5 years previously with a history of sigmoid colon cancer; anterior resection and chemotherapy was performed. Three years later, lung metastases developed, and he was treated with chemotherapy. FDG-PET/CT scans revealed a new nodule showed focal activity in the right lobe of the thyroid gland.

Initially, the thyroid nodule was regarded as metastatic colon cancer. However, he was diagnosed with thyroid medullary carcinoma by fine needle aspiration biopsy cytology. Serum calcitonin level was elevated 17.3pg/mL (normal range 0-10pg/mL) and serum CEA was 29.31ng/mL (normal range 0-4.7ng/mL). RET proto-oncogene mutations were not detected. Total thyroidectomy and bilateral central neck dissection were performed.

Cut sections revealed a well circumscribed round gray-tan nodular mass, measuring 1.5x1.2cm. There is an ill defined white solid mass with central irregular yellow necrosis, measuring 0.8x0.7cm. Histological examination and Immunohistochemical stains revealed metastatic colonic adenocarcinoma in medullary carcinoma of thyroid.

Malignant metastases are rarely found in the thyroid gland, the incidence reaching approximately 2% of all thyroid malignant neoplasms. They are most often caused by tumours of the kidneys, lungs, mammary glands, ovary, and colon or by melanomas. But, tumor to tumor metastasis to thyroid cancer is extremely rare. To our knowledge, only several cases have reported in the literature(The donor tumor cells infiltrated the substance
of the follicular variant of papillary thyroid carcinoma). The present patient is the first case of colorectal carcinoma metastazing to medullary carcinoma of thyroid.

(1) Zubair WB et al., Arch Pathol Lab Med. 1999;123:703–706 (2) Martin HC et al., World Journal of Surgical Oncology 2008, 6:122 (3) Shimaoka KS et al., Cancer 1962,15:557-565 (4) Fujita T et al., Int J Clin Oncol 2004,9:515-519

Nothing to Disclose: JM, SK, CHK, KYL

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