Thyroid transcription factor-1 expression in thyroid-like nasopharyngeal papillary adenocarcinoma: report of 2 cases

We present the cases of 2 pediatric patients with low-grade nasopharyngeal papillary adenocarcinoma with features suggestive of thyroid origin. Both cases showed strong nuclear immunoreactivity for thyroid transcription factor-1 protein and positive immunostaining for cytokeratins 7 and 19. After thyroid imaging studies, local excision was performed in both patients. The patients remain free of disease 2 and 15 years after treatment, with no evidence of lesions in the thyroid or elsewhere.