The role of CK7, Ki-67, CD34 and vimentin in the differentiation between biliary atresia and idiopathic neonatal hepatitis in Egyptian cholestatic neonates HAYAM ABDEL SAMIE AIAD, 1 MONA ABDEL HALIM KANDIL, 1 REHAB MONIR SAMAKA, 1 MERVAT MAHMOUD SULTAN, 2 MOHAMED TAWFIK BADR 2 and GAMMAL ELDIN MAHMOUD NADA 3 1 Department of Pathology, Faculty of Medicine, Menoufiya University, Menoufiya, Egypt; 2 Department of Pathology, National Liver Institute, Menoufiya University, Menoufiya, Egypt; and 3 Department of Pathology, Faculty of Medicine, Cairo University, Cairo, Egypt Aiad HAS, Kandil MAH, Samaka RM, Sultan MM, Badr MT, Nada GEM. The role of ck7, ki-67, cd34 and vimentin in the differentiation between biliary atresia and idiopathic neonatal hepatitis in egyptian cholestatic neonates. APMIS 2012. The differentiation between biliary atresia (BA) and idiopathic neonatal hepatitis (INH) is challenging with many histological overlaps especially in the first weeks of life. This study aimed to investigate the role of immunohistochemical staining of CK7, Ki67, CD34, and vimentin in addition to other clinico- pathological features in the differentiation between BA and INH. Cases included 30 infants with BA and 30 infants with INH. The diagnosis was based on clinical, laboratory, and liver biopsy examina- tion. Female gender and elevated serum gamma glutamyle transferase were in favor of BA. Portal tract changes, such as bile ductular proliferation documented by CK7, Ki67 immunostaining and angiogene- sis documented by CD34 immunostaining, favored the diagnosis of BA. Copper associated protein was positive in 70% of BA cases, but not detected in INH cases. Parenchymatous changes, such as giant cell transformation and positive iron deposition and Kupffer cell proliferation documented by vimentin immunostaining, favored the diagnosis of INH.CK7, Ki67, CD34, and vimentin are helpful adjuvant immunostaining in the differentiation between BA and INH. Key words: Ck7; Ki-67; CD34; vimentin; biliary atresia; idiopathic neonatal hepatitis. Hayam Abdel Samie Aiad, Department of Pathology, Faculty of Medicine, Menoufiya University, Menoufiya, Egypt. e-mail: hayamaiad@yahoo.com Neonatal cholestasic disorders are a group of hepatobiliary diseases occurring within the first 3 months of life. The incidence of neonatal cho- lestasis is around 1 in 2500 live births in the west (1). The two most common causes of neonatal cholestasis are biliary atresia (BA) and idio- pathic neonatal hepatitis (INH). The differentia- tion between both diseases is of crucial importance because surgical treatment of BA should be performed as early as possible to avoid liver cirrhosis and liver transplantation (2). Also, INH misdiagnoses will result in unnecessary laparotomy and delayed right man- agement. The clinical presentation of BA and INH is almost similar and the differential diagnosis is sometimes challenging (3). It was reported that, the accurate diagnostic test for differentiating BA and INH is percutaneous liver biopsy, if an adequate size is obtained and examined by expe- rienced pathologist (4). Received 11 July 2011. Accepted 28 November 2011 APMIS Ó 2012 The Authors APMIS Ó 2012 APMIS DOI 10.1111/j.1600-0463.2011.02859.x 1