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Int J Clin Exp Pathol 2013;6(4):798-801

Case Report
Cytokeratin positivity in anaplastic large cell lymphoma: a potential diagnostic pitfall in
misdiagnosis of metastatic carcinoma

Qingfu Zhang, Jian Ming, Siyang Zhang, Bo Li, Xue Han, Xueshan Qiu

Department of Pathology, the First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, PR China;
Department of Pathology, No. 202 Hospital of People Liberation Army of China, Shenyang, PR China; Center of Laboratory Technology and
Experimental Medicine, China Medical University, Shenyang, PR China; Department of Obstetrics and Gynecology, Shengjing Hospital of China
Medical University, Shenyang, PR China

Received January 26, 2013; Accepted February 21, 2013; Epub March 15, 2013; Published April 1, 2013

Abstract: Cytokeratin (pan) and epithelial membrane antigen (EMA) were considered as commonly useful epithelial markers to distinguish
cancer from lymphoma, but the expression of cytokeratin (pan) and EMA had also been seen in some lymphomas. Here, we presented an
unusual case of anaplastic large cell lymphoma (ALCL) absence of some lymphoid markers (Including CD3, CD20, Pax-5, CD45Ro) and
positive for cytokeratin (pan) and EMA, which was misdiagnosed as metastatic carcinoma. Our case suggested that the epithelial markers
(including cytokeratin and EMA) show an overlap with that of ALCL, which represented a diagnostic pitfall for confusing ALCL with metastatic
carcinoma. (IJCEP1301054).

Keywords: Anaplastic large cell lymphoma, anaplastic lymphoma kinase, immunohistochemistry

Address correspondence to: Dr. Xueshan Qiu, Department of Pathology, the First Affiliated Hospital and College of Basic Medical Sciences,
China Medical University. No. 92 North Second Road, Heping District, Shenyang 110001, China. E-mail: cmupathology@163.com