LAUSR

Histiocytic sarcoma (HS) is a very uncommon malignant proliferation accounting for less than 1% of all neoplasms of hematopoietic and lymphoid tissues. According to the 2008 WHO classification of haematological and lymphoid tumours, diagnosis of HS requires histological and immunohistochemical evidence of histiocytic differentiation [1]. The 2016 Central nervous system (CNS) WHO classification parallels the categories of the corresponding WHO classification of hematopoietic and lymphoid tissues. By definition, diagnosis of HS relies on the expression of at least two of the histiocytic markers, e.g. CD68, lysozyme and CD163, the latter being considered as the most specific marker [2]. HS may be localized or may disseminate, mimicking malignant histiocytosis and occurs in various locations [3]. CNS involvement is extremely rare and to date only 29 cases have been reported [4, 5]. In the CNS, HS develops in any cerebral structure, at any age and both sexes are equally affected. This article is protected by copyright. All rights reserved.