title: Metastasis of colon cancer to medullary thyroid carcinoma: a case report.
abstract: Metastasis to the primary thyroid carcinoma is extremely rare. We report here a case of colonic adenocarcinoma metastasis to medullary thyroid carcinoma in a 53-yr old man with a history of colon cancer. He showed a nodular lesion, suggesting malignancy in the thyroid gland, in a follow-up examination after colon cancer surgery. Fine needle aspiration biopsy (FNAB) of the thyroid gland showed tumor cell clusters, which was suspected to be medullary thyroid carcinoma (MTC). The patient underwent a total thyroidectomy. Using several specific immunohistochemical stains, the patient was diagnosed with colonic adenocarcinoma metastasis to MTC. To the best of our knowledge, the present patient is the first case of colonic adenocarcinoma metastasizing to MTC. Although tumor-tumor metastasis to primary thyroid carcinoma is very rare, we still should consider metastasis to the thyroid gland, when a patient with a history of other malignancy presents with a new thyroid finding.
authors.affiliation: Department of Internal Medicine, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon, Korea.
authors.forename: So-Jung
authors.identifier: 0000-0003-1380-2304
authors.initials: SJ
authors.lastname: Yeo
authors.affiliation: Department of Internal Medicine, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon, Korea.
authors.forename: Kyu-Jin
authors.identifier: 0000-0003-1629-6144
authors.initials: KJ
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon, Korea.
authors.forename: Bo-Yeon
authors.identifier: 0000-0002-3658-2351
authors.initials: BY
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon, Korea.
authors.forename: Chan-Hee
authors.identifier: 0000-0001-8988-0187
authors.initials: CH
authors.lastname: Jung
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon, Korea.
authors.forename: Seung-Won
authors.initials: SW
authors.lastname: Lee
authors.affiliation: Department of Pathology, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon, Korea.
authors.forename: Jeong-Ja
authors.initials: JJ
authors.lastname: Kwak
authors.affiliation: Department of Internal Medicine, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon, Korea.
authors.forename: Chul-Hee
authors.identifier: 0000-0002-1911-138X
authors.initials: CH
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon, Korea.
authors.forename: Sung-Koo
authors.identifier: 0000-0002-8194-7233
authors.initials: SK
authors.lastname: Kang
authors.affiliation: Department of Internal Medicine, Soonchunhyang University College of Medicine, Bucheon Hospital, Bucheon, Korea.
authors.forename: Ji-Oh
authors.identifier: 0000-0003-4882-1606
authors.initials: JO
authors.lastname: Mok
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000601:surgery; D044963:Biopsy, Fine-Needle; D018276:Carcinoma, Medullary / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000556:secondary*; D018278:Carcinoma, Neuroendocrine; D003110:Colonic Neoplasms / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D016609:Neoplasms, Second Primary / Q000175:diagnosis*; D011859:Radiography; D013961:Thyroid Gland / Q000473:pathology; D013964:Thyroid Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000556:secondary*; D016606:Thyroid Nodule / Q000175:diagnosis
keywords: Colorectal Neoplasms; Neoplasm Metastasis; Thyroid Neoplasms