Pediatric mediastinal ALK- negative anaplastic large cell lymphoma (Hodgkin-like pattern) in a 13-year-old girl: a case report and review of literature.

Anaplastic large-cell Lymphoma (ALCL) is a rare type of non-Hodgkin lymphoma that is characterized by an entity of large neoplastic cells labeled by the Ki-1 antibody. It constitutes ~2% of all lymphoid neoplasms and is divided into two main categories: anaplastic large-cell kinase (ALK)+ALCL and ALK-ALCL that is recognized by the absence of ALK expression and mostly affects men at older ages. Thus, in this report we present a rare case of ALK-negative ALCL (ALK-ALCL) that was described and diagnosed in a 13-year-old girl in the mediastinum. Highlighting the rarity of manifestation at younger ages and the importance of using immunohistochemical staining in the differential diagnosis of this lymphoid neoplasm.