Anaplastic large cell lymphoma: clinicopathological and immunohistochemical study of 20 cases classified according to the 2016 revision of the World Health Organization classification of lymphoid neoplasms

Abstract

Anaplastic large cell lymphoma (ALCL) is a type of non-Hodgkin lymphoma composed of CD30-positive neoplastic cells. The 2016 revision of the WHO classification of lymphoid neoplasms includes anaplastic lymphoma kinase (ALK) positive, ALK negative and breast implant associated ALCL. ALCL have distinct clinical and prognostic features between positive and negative cases. ALK-1 positive cases mostly occur in the first three decades of life while patients with ALK-1 negative are older. ALCL exhibit a very broad range of cytology appearances that include common pattern, lymphohistiocytic pattern, small-cell pattern, Hodgkin-like pattern and composite pattern. By definition, ALCL show strong CD30 staining on the cell membrane and in the Golgi region and the majority are epithelial membrane antigen positive, express one or more T-cell or Natural Killer antigens and are constantly negative for Epstein-Barr virus. We present the clinicopathologic and immunohistochemical analysis of 20 cases of ALCL studied at a single institution, classified according to the 2016 revision of lymphoid neoplasms. Nine cases were ALK-1 positive, ten ALK-1 negative, and one case as a breast implant associated ALCL ALK-1 negative. (creativecommons.org/licenses/by-nc-nd/4.0/).