Review ArticlesThe Spectrum of Papillary Thyroid Carcinoma VariantsKhanafshar, Elham MD, MS*; Lloyd, Ricardo V. MD, PhD† Author Information *Department of Pathology, University of California, San Francisco, CA †Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, WI Reprints: Elham Khanafshar, MD, MS, Department of Pathology, University of California, 1600 Divisadero Street, Rm R200 San Francisco, 94115 CA (e-mail: [email protected]). Advances in Anatomic Pathology: January 2011 - Volume 18 - Issue 1 - p 90-97 doi: 10.1097/PAP.0b013e3182026da6 Buy Metrics Abstract Papillary thyroid carcinoma is the most common type of thyroid malignancy. The diagnostic features of these tumors include characteristic nuclear cytology. However, many variants have been reported with different morphology and molecular profiles. Although the vast majority of papillary thyroid carcinomas have an excellent prognosis, some variants of papillary thyroid carcinoma can have a more aggressive course. With this increased attention to papillary thyroid carcinoma variants has come the need to sort out which variants are clinically important and should be recognized by practicing pathologists. The main objectives of this review article are to (1) summarize the gross and histopathologic features of papillary thyroid carcinoma; (2) provide an overview of the subtypes of papillary thyroid carcinoma and their prognosis; (3) discuss established and emerging data on the immunohistochemical findings that are helpful in differential diagnosis; and (4) summarize molecular findings and pathogenesis of these lesions. © 2011 Lippincott Williams & Wilkins, Inc.