title: Primary leptomeningeal lymphoma in a patient with concomitant CD4+ lymphocytopenia.
abstract: BACKGROUND
  Idiopathic CD4+ lymphocytopenia (ICL) is a rare disorder in which patients have mild and/or severe opportunistic infections or maybe without symptoms. The etiology is currently unknown. Diagnosis is made by excluding retroviral infections (human immunodeficiency virus-1 or -2, human T cell lymphotropic virus-1 or -2) or other known causes of immunosuppression.
  
  
  OBJECTIVE
  To provide a case report of a patient with possible ICL who presented with a rare form of primary non-Hodgkin lymphoma (NHL) of the central nervous system (CNS). Review of the literature has identified only five other patients with NHL and ICL; however, none of these had a CNS lymphoma.
  
  
  RESULTS
  We describe a patient with possible ICL, and address links between lymphopenia and lymphoproliferative disorders.
  
  
  CONCLUSIONS
  Although not uncommon for patients infected with human immunodeficiency virus to develop CNS NHL, this is the first case of a possible ICL patient with such a lymphoma. This case revisits an important relationship between lymphopenia and lymphoproliferative disorders.
authors.affiliation: Division of Clinical Immunology, Mount Sinai Medical Center, New York, New York 10029, USA. paula.busse@mssm.edu
authors.forename: Paula J
authors.initials: PJ
authors.lastname: Busse
authors.forename: Charlotte
authors.initials: C
authors.lastname: Cunningham-Rundles
mesh_terms: D000328:Adult; D018791:CD4 Lymphocyte Count; D005500:Follow-Up Studies; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000150:complications*; D008231:Lymphopenia / Q000150:complications* / Q000209:etiology / Q000276:immunology; D008297:Male; D008577:Meningeal Neoplasms / Q000150:complications*