Table 1.

Clinical course

	Initial presentation	6 years follow-up	12 years follow-up	14 years follow-up
Clinical presentation	6.0 cm left thyroid mass with extrathyroidal extension and tracheal invasion	Left neck subcutaneous/soft tissue nodule with distant metastases to the lung	Multiple new lung and neck metastases	Progression of cervical disease with development of spinal metastases
Laboratory tests	Normal serum TG (2.9 ng/mL); normal serum TSH (1.54 mcUnits/mL); normal free T4 (1.24 ng/mL)	Low serum TSH (0.48 mlU/L); serum TG not performed	Normal serum TSH (0.88 mlU/L); normal free T4 (1.47 ng/dL); serum TG not performed	High serum TSH (10.24 mlU/L); low free serum T3 (1.9 pg/mL)
Original pathologic diagnosis	Adenocarcinoma of minor salivary glands likely originating from the trachea	Metastatic salivary gland adenocarcinoma of probable tracheal origin	Metastatic SC of probable tracheal origin	Metastatic SC of probable tracheal origin
Revised pathologic diagnosis	SC of the thyroid	Metastatic SC of the thyroid	Metastatic SC of the thyroid	Metastatic SC of the thyroid
Stage	T4aN1M0
Treatment	Initial left hemithyroidectomy with limited tracheal wall resection, followed by completion right thyroidectomy with laryngopharyngectomy and external beam RT (6000 cGy)	Therapeutic bilateral lung wedge resections and close surveillance of recurrent cervical disease	First generation TRK inhibitor (Larotrectinib)	RT Investigational second generation TRK inhibitor (5 months) followed by chemotherapy

RT Radiation therapy