CME Review Article #5Diffuse Large B-Cell Lymphoma of the Thyroid Mimicking Thyroid Carcinoma A Plea for Open BiopsyLimmer, Stefan MD*; Bruch, Hans-Peter MD†; Baehre, Manfred MD‡; Czymek, Ralf MD§; Eckmann, Christian MD¶ Author Information *Head of the Department of Endocrine Surgery, Department of Surgery; †Head of the Department of Surgery, Department of Surgery; ‡Head of the Department of Nuclear Medicine; §Staff, Department of Surgery; ¶Former Head of the Department of Endocrine Surgery, Centre of Thyroid Diseases, University Hospital of Schleswig-Holstein, Luebeck, Germany. The authors have disclosed that they have no significant relationships with or financial interests in any commercial organizations pertaining to this educational activity. All staff in a position to control the content of this CME activity have disclosed that they have no financial relationships with, or financial interests in, any commercial companies pertaining to this educational activity. Lippincott CME Institute has identified and resolved all faculty and staff conflicts of interest regarding this educational activity. Reprints: Stefan Limmer, MD, Department of Surgery, University Hospital of Schleswig-Holstein Campus, Luebeck, Ratzeburger Allee 160, 23538 Luebeck, Germany. E-mail: [email protected]; or [email protected]. Chief Editor's Note:This article is the 5th of 18 that will be published in 2009 for which a total of up to 18 AMA PRA Category 1 Credits™ can be earned. Instructions for how credits can be earned precede the CME Examination at the back of this issue. The Endocrinologist 19(2):p 82-84, March 2009. | DOI: 10.1097/TEN.0b013e318198b427 Buy CME Test Metrics Abstract Anaplastic thyroid carcinoma (ATC) and thyroid lymphoma (TL) are both in the differential diagnoses of a malignant thyroid tumor. With a similar history and clinical characteristics, it can often be difficult to distinguish ATC from TL. Ultimately, they can be reliably differentiated only by histopathology. This article presents 3 patients with lymphoma of the thyroid, who initially showed all the clinical signs of an ATC. Fine needle aspiration was performed in all 3 cases but did not provide a reliable pathologic diagnosis. The diagnosis of a primary TL was confirmed only by open surgical biopsy. © 2009 Lippincott Williams & Wilkins, Inc.