title: Monoclonal B-cell population mimicking lymphoma in a patient with multiple sclerosis.
abstract: BACKGROUND
  Diagnosis of intraparenchymal brain lesions has usually required invasive diagnostic procedures, because too few cells are shed into cerebrospinal fluid to permit cytologic diagnosis. Polymerase chain reaction technology makes it possible to identify cell populations that are present at a much lower frequency than traditional techniques.
  
  
  METHODS
  A young woman presented with multiple brain lesions raised the question of primary central nervous system lymphoma. Polymerase chain reaction analysis of cerebrospinal fluid showed evidence of a monoclonal B-cell population heightening suspicion of lymphoma. Brain biopsy showed acute demyelination most consistent with multiple sclerosis.
  
  
  CONCLUSIONS
  Although T-cell restriction has been demonstrated in multiple sclerosis lesions, the finding of a monoclonal B-cell population was unexpected and to our knowledge has not been previously reported. This case emphasizes that monoclonality is not always indicative of a neoplastic process, particularly in the central nervous system.
authors.affiliation: Department of Pathology, Brown University School of Medicine, Providence, Rhode Island, USA.
authors.forename: C
authors.initials: C
authors.lastname: Young
authors.forename: N
authors.initials: N
authors.lastname: Gordon
authors.forename: H P
authors.initials: HP
authors.lastname: Safran
authors.forename: S
authors.initials: S
authors.lastname: Schatz
authors.forename: E
authors.initials: E
authors.lastname: Stopa
authors.forename: T C
authors.initials: TC
authors.lastname: King
mesh_terms: D000328:Adult; D001483:Base Sequence; D001707:Biopsy, Needle; D001927:Brain Diseases / Q000134:cerebrospinal fluid / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D016393:Lymphoma, B-Cell / Q000134:cerebrospinal fluid / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008969:Molecular Sequence Data; D009103:Multiple Sclerosis / Q000134:cerebrospinal fluid / Q000473:pathology*; D016133:Polymerase Chain Reaction
chemical_list: D007143:Immunoglobulin Heavy Chains