Anaplastic (Undifferentiated) Carcinoma Yuri E. Nikiforov Raja R. Seethala DEFINITION Anaplastic carcinoma is a highly aggressive malignant thyroid tumor composed of undifferentiated cells that demonstrate immunohistochemical or ultrastructural features of…
Tumors Metastatic to the Thyroid Lester D.R. Thompson DEFINITION Tumors developed in the thyroid gland as a result of lymphatic or hematogenous spread from distant sites are considered metastatic disease…
Gross Examination Raja R. Seethala Yuri E. Nikiforov INTRODUCTION An understanding of the normal surgical thyroid anatomy is a requisite for accurate gross characterization of lesions. The fundamentals of thyroid…
Molecular Testing of Thyroid FNA Samples Marina N. Nikiforova Yuri E. Nikiforov Molecular testing of thyroid fine needle aspiration (FNA) samples is gaining its use as an ancillary diagnostic tool…
Follicular Adenoma Yuri E. Nikiforov N. Paul Ohori DEFINITION Follicular adenoma is a benign, encapsulated, noninvasive tumor originating from thyroid follicular cells. When used without additional qualifiers, this term typically…
Poorly Differentiated Carcinoma Yuri E. Nikiforov DEFINITION Poorly differentiated thyroid carcinoma is an aggressive malignant tumor of follicular cell origin that is characterized by a partial loss of thyroid differentiation…
Diffuse and Nodular Hyperplasia Paul W. Biddinger GRAVES DISEASE (DIFFUSE TOXIC HYPERPLASIA) Definition Graves disease, also known as diffuse toxic hyperplasia or diffuse toxic goiter, is an autoimmune disorder characterized…
Thyroiditis Paul W. Biddinger Thyroiditis encompasses a heterogeneous group of inflammatory diseases of the thyroid. The study of these inflammatory conditions can be challenging because of the different approaches to…
Hyalinizing Trabecular Tumor Yuri E. Nikiforov DEFINITION Hyalinizing trabecular tumor is a rare noninvasive follicular cellderived thyroid neoplasm with a characteristic trabecular growth pattern and intratrabecular hyalinization. The malignant potential…
Other Nonneoplastic Disorders Paul W. Biddinger AMIODARONE-INDUCED THYROID DISEASE Amiodarone is an iodinated drug used for the treatment of cardiac arrhythmias. Although an effective drug for arrhythmias, amiodarone can produce…
