title: Histiocytic sarcoma as a secondary malignancy: pathobiology, diagnosis, and treatment.
abstract: Histiocytic sarcoma (HS) is an extremely rare non-Langerhans cell disorder with an aggressive course and limited treatment options. Recent advances in molecular/genetic sequencing have suggested a common clonal origin between various hematolymphoid disorders and cases of secondary HS. Deriving conclusions from previously reported cases of HS arising secondarily to certain hematolymphoid disorders, here we have tried to provide insight into the mechanisms influencing this evolution. We also discuss a clinical case of a 72-year-old man with a diagnosis of chronic myeloid leukemia (CML), presenting subsequently with a heterogeneous liver mass positive with a diagnosis of HS. The liver mass showed a retained BCR-ABL1 translocation suggesting clonality between the CML and HS. As seen in our case and other reported cases of HS derived secondarily, the concurrent expression of immunoglobulin heavy (IGH)-/light-chain rearrangements or cytogenetic markers common to the primary malignancy suggests an evolutionary mechanism involving lineage switching that could potentially be influenced by genetic or epigenetic cues which may occur at the level of a progenitor or the malignant cell itself.
authors.affiliation: Feist-Weiller Cancer Center, LSU Health, Shreveport, LA, USA.
authors.forename: Junaid
authors.initials: J
authors.lastname: Ansari
authors.affiliation: University of Buffalo, Buffalo, NY, USA.|Roswell Park Cancer Institute, Buffalo, NY, USA.
authors.forename: Abdul Rafeh
authors.initials: AR
authors.lastname: Naqash
authors.affiliation: Feist-Weiller Cancer Center, LSU Health, Shreveport, LA, USA.
authors.forename: Reinhold
authors.initials: R
authors.lastname: Munker
authors.affiliation: Feist-Weiller Cancer Center, LSU Health, Shreveport, LA, USA.
authors.forename: Hazem
authors.initials: H
authors.lastname: El-Osta
authors.affiliation: Feist-Weiller Cancer Center, LSU Health, Shreveport, LA, USA.
authors.forename: Samip
authors.initials: S
authors.lastname: Master
authors.affiliation: Department of Pathology, LSU Health, Shreveport, LA, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Cotelingam
authors.affiliation: Roswell Park Cancer Institute, Buffalo, NY, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Griffiths
authors.affiliation: Feist-Weiller Cancer Center, LSU Health, Shreveport, LA, USA.
authors.forename: Adam H
authors.initials: AH
authors.lastname: Greer
authors.affiliation: Feist-Weiller Cancer Center, LSU Health, Shreveport, LA, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Yin
authors.affiliation: Feist-Weiller Cancer Center, LSU Health, Shreveport, LA, USA.
authors.forename: Prakash
authors.initials: P
authors.lastname: Peddi
authors.affiliation: Department of Pathology, LSU Health, Shreveport, LA, USA.
authors.forename: Rodney E
authors.initials: RE
authors.lastname: Shackelford
mesh_terms: D000368:Aged; D001706:Biopsy; D001853:Bone Marrow / Q000473:pathology; D065150:Cellular Reprogramming; D003937:Diagnosis, Differential; D044127:Epigenesis, Genetic; D059014:High-Throughput Nucleotide Sequencing; D054747:Histiocytic Sarcoma / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology* / Q000628:therapy*; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000175:diagnosis / Q000188:drug therapy; D008297:Male; D009154:Mutation; D016609:Neoplasms, Second Primary / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology* / Q000628:therapy*
keywords: BRAF; epigenetics; histiocytic sarcoma; lineage switching; transdifferentiation