Primary pulmonary histiocytic sarcoma with CNS metastasis: a case report and molecular profiling insights.

ABSTRACT: Histiocytic sarcoma (HS), reclassified in the WHO fifth edition as a Histiocytic/dendritic cell neoplasms, represents a rare hematopoietic malignancy with extranodal predominance and aggressive clinical behavior. This study reports the case of a 53-year-old female diagnosed with primary pulmonary HS, who presented with a 60-mm mass in the right middle lobe and later developed fatal brain metastases. Using a combination of pathology, whole-exome sequencing, and fusion gene analysis, we identified key molecular drivers of tumor development and spread. Major findings include the concurrent activation of the RAS/MAPK and PI3K/mTOR pathway activation (118 combined gene variants), TP53 biallelic inactivation, HLA locus alterations, and persistent LOC285045 fusions. Drug sensitivity profiling sug

SUBMITTER: Chen K 

PROVIDER: S-EPMC12920180 | biostudies-literature | 2026

REPOSITORIES: biostudies-literature