AUTHOR=Zhou Yuhang , Hurtado-Castillo Marisabel , Pandey Om 

TITLE=Case report: ALK-positive histiocytosis presented as bilateral synchronous breast masses with long-term remission on crizotinib

JOURNAL=Frontiers in Medicine

VOLUME=10

YEAR=2023

URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2023.1288849

DOI=10.3389/fmed.2023.1288849

ISSN=2296-858X

ABSTRACT=<p>ALK-positive histiocytosis (APH) is a rare type of histiocytic neoplasm with characteristic <italic>ALK</italic> (Anaplastic Lymphoma Kinase) gene translocation and fusion, with only 27 reported cases in the literature. In this study, we report the first case of synchronous bilateral breast involvement of ALK-positive histiocytosis on initial presentation in a 46-year-old Hispanic woman. APH was diagnosed by the confirmation of clonal histiocyte proliferation with ALK overexpression on IHC and the presence of <italic>KIF5B-ALK</italic> gene fusion from her breast and lung biopsies. The patient in our study is currently under complete and long-term remission with crizotinib treatment (an ALK inhibitor). This report expands on the clinical manifestation of APH, emphasizes the importance of ALK detection in histiocytic diseases, and provides the efficacy and long-term prognosis of the ALK inhibitor therapy for APH.</p>