===Resident Questions===
* <spoiler text="Diagnosis?">* Lymphocytic thyroiditis (Hashimoto thyroiditis). </spoiler>
* <spoiler text="What are the clinical findings that support this diagnosis?">
* The diagnosis of Hashimoto is based on one or more circulating autoantibodies. The most common are anti-thyroglobulin and anti-thyroid peroxidase (TPO).
==Additional Teaching Points=====Immunohistochemistry===* TTF-1 (nuclear stain)** Thyroid Transcription factor1 regulates transcription of genes specific to the thyroid, lung, and diencephalon** If metastatic thyroid cancer to the lung is ruled out by morphology or +thyroglobulin; then a +TTF1 supports adenocarcinoma originating from the lung* P63 (nuclear stain) and 34BE12 (cytoplasmic stain)** Used for squamous differentiation* TTF1 is more sensitive than p63** If a tumor stains for both it is more likely to be adenocarcinoma* Napsin A(cytoplasmic stain)** Granular staining pattern** Marker for adenocarcinoma
{{Cytologically Yours}}
