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.
Adenocarcinoma/pathology/surgery ; Biopsy, Fine-Needle ; Carcinoma, Medullary/diagnosis/radiography/*secondary ; Colonic Neoplasms/*pathology/surgery ; Humans ; Male ; Middle Aged ; Neoplasms, Second Primary/*diagnosis ; Thyroid Gland/pathology ; Thyroid Neoplasms/diagnosis/radiography/*secondary ; Thyroid Nodule/diagnosis

Ectopic thyroid glands generally occur in the midline as a result of abnormal median migration, and their presence lateral to the midline is rare. We present one case of an ectopic thyroid gland masquerading as a lateral neck metastasis of a papillary thyroid carcinoma (PTC). In this case of a 54-yr-old woman with left PTC, we suspected left lateral neck metastasis on preoperative neck computed tomography. The patient underwent total thyroidectomy, central compartment neck dissection, and left modified radical neck dissection (MRND). The patient was diagnosed as having an accessory thyroid gland on the lateral neck on the final pathologic report. Surgeons should be aware of the existence of an ectopic thyroid gland in unusual locations.
Biopsy ; Carcinoma, Papillary/radiography/*secondary ; Choristoma/*pathology/radiography ; Diagnosis, Differential ; Female ; Humans ; Middle Aged ; Neck ; *Thyroid Gland ; Thyroid Neoplasms/*pathology/radiography ; Tomography, X-Ray Computed

Lateral neck node metastasis is an important prognostic factor in thyroid carcinoma. We developed a scoring system for use in prediction of lateral neck node metastasis from papillary thyroid cancer. In this study, 161 consecutive patients were included in the training data set. This scoring system, named the Yonsei Estimated Value (YEV) for lymph node metastasis in papillary thyroid cancer, was developed on the basis of results from multivariate logistic regression analysis of preoperative clinical and radiologic data. Sixty eight consecutive patients were included for testing of the validity of the scoring system. The equation for prediction of lateral neck node metastasis was follows: YEV (Yonsei Estimated Value) = 1/(1+X) X = Exp (5.333-[0.902 x sex]+[0.036 x age]-[1.020 x tumor size]-[0.177 x lymph node size]-[0.032 x lymph node density]) When the YEV was 0.3 or more, the probability of lateral neck node metastasis was 79.0%, with sensitivity of 76.3%, specificity of 69.8%, positive predictive value of 56.7%, and negative predictive value of 85.1% in the training set. When fine needle aspiration biopsy for suspicious lateral neck nodes is not possible, or the results are inadequate, our scoring system for prediction of lateral neck node metastasis can be helpful in optimization of the surgical extent for each patient.
Adolescent ; Adult ; Aged ; Algorithms ; Female ; Head and Neck Neoplasms/*diagnosis/secondary ; Humans ; Logistic Models ; Lymphatic Metastasis/*diagnosis ; Male ; Middle Aged ; *Predictive Value of Tests ; Thyroid Neoplasms/*pathology/radiography ; Tomography, X-Ray Computed