Metastasis of distal esophageal carcinoma to the thyroid with presentation simulating primary thyroid carcinoma: a case report and review of the literature.

Metastasis to the thyroid is extremely rare. There is a lack of awareness of and adequate preparation for this situation, especially in an individual without a past history of malignancy. We describe a rare case of a 61-year-old man in whom a primary distal esophageal carcinoma gave rise to a metastatic palpable mass in the thyroid gland. Palliative bilateral near-total thyroidectomy was performed with pathology showing squamous cell carcinoma and tracheostomy was carried out simultaneously due to airway compression with related symptoms. A review of the literature only reveals 4 similar cases. Secondary neoplasm of the thyroid mimicking a primary malignant lesion is seldom encountered, however, in order to make appropriate treatment, the most critical problem is to distinguish the difference between the above two and the final diagnosis can only be confirmed on pathologic examination. Although the prognosis of thyroid metastasis is commonly felt to be poor, improvement of living quality and prolongation of survival may be obtained in such patients through correct diagnosis and treatment.

A model to discriminate malignant from benign thyroid nodules using artificial neural network.

OBJECTIVE: This study aimed to construct a model for using in differentiating benign and malignant nodules with the artificial neural network and to increase the objective diagnostic accuracy of US. MATERIALS AND METHODS: 618 consecutive patients (528 women, 161 men) with 689 thyroid nodules (425 malignant and 264 benign nodules) were enrolled in the present study. The presence and absence of each sonographic feature was assessed for each nodule - shape, margin, echogenicity, internal composition, presence of calcifications, peripheral halo and vascularity on color Doppler. The variables meet the following criteria: important sonographic features and statistically significant difference were selected as the input layer to build the ANN for predicting the malignancy of nodules. RESULTS: Six sonographic features including shape (Taller than wide, p<0.001), margin (Not Well-circumscribed, p<0.001), echogenicity (Hypoechogenicity, p<0.001), internal composition (Solid, p<0.001), presence of calcifications (Microcalcification, p<0.001) and peripheral halo (Absent, p<0.001) were significantly associated with malignant nodules. A three-layer 6-8-1 feed-forward ANN model was built. In the training cohort, the accuracy of the ANN in predicting malignancy of thyroid nodules was 82.3% (AURO  = 0.818), the sensitivity and specificity was 84.5% and 79.1%, respectively. In the validation cohort, the accuracy, sensitivity and specificity was 83.1%, 83.8% and 81.8%, respectively. The AUROC was 0.828. CONCLUSION: ANN constructed by sonographic features can discriminate benign and malignant thyroid nodules with high diagnostic accuracy.