Abstract:

Wang Baihe, Song Hao, Chen Hao, Jiang Yiqun, Xu Xiulian, Zhang Wei Department of Pathology, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing 210042, China Corresponding author: Xu Xiulian, Email: xxlqjl@sina.com；Zhang Wei, Email: ifmtjoel@163.com 【Abstract】 Objective To investigate clinicopathological features and differential diagnosis of clear cell acan-thoma （CCA）. Methods Clinical and pathological data on 10 patients with CCA were retrospectively reviewed. Results CCA clinically manifested as widespread, well-circumscribed, hemispherical dark red to brown papules and nodules with ulcerative, hemorrhagic or desquamative surfaces. Most patients had no subjective symptoms. Nine patients had solitary lesions, and 1 patient had multiple lesions. It frequently occurred in the middle-aged or elderly. Histopathological examination showed thickened prickle cell layer, and the tumor was composed of large clear cells with pale-staining cytoplasm. Characteristic pathological findings were scattered neutrophils and nuclear dust in the epidermis. Periodic acid-Schiff （PAS） staining without diastase was positive in all the 10 patients. Immunohisto-chemical study revealed that tumor cells expressed epithelial membrane antigen （EMA） and keratin, but did not express carcinoembryonic antigen （CEA）. Conclusions CCA has no obvious clinical characteristics, and is easily misdiagnosed as melanocytic or vascular tumors. However, CCA has typical histological changes, and histopathological examination is the gold standard for its diagnosis.