title: Cutaneous findings associated with chronic natural killer cell lymphocytosis.
abstract: BACKGROUND
  Chronic Natural Killer Cell Lymphocytosis (CNKL) is a recently described rare proliferative disorder. We noted an association of cutaneous disorders with CNKL in our clinical experience.
  
  
  METHODS
  We reviewed the medical records of all known patients with CNKL at our institution.
  
  
  RESULTS
  Five of 14 patients (36%) with CNKL had associated chronic cutaneous disease: two had livedoid vasculopathy; one, urticarial vasculitis; one, peripheral T-cell lymphoma; and one had complex recurrent aphthous stomatitis. In each case, except the one with lymphoma, the cutaneous disease was present before CNKL was diagnosed and CNKL persisted for the duration of the cutaneous disease. All five patients had increased numbers of large granular lymphocytes on a peripheral blood smear and three or four in the bone marrow (one patient did not undergo bone marrow biopsy).
  
  
  CONCLUSIONS
  Although CNKL and the reported skin diseases have occurred in the same patients, a causal link cannot yet be established. With CNKL, dermatologists must recognize associated cutaneous diseases, monitor patients for systemic disorders and cytopenias, and appropriately refer patients to a hematologist.
authors.affiliation: Department of Dermatology, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Erin R
authors.initials: ER
authors.lastname: Vanness
authors.forename: Mark D P
authors.initials: MD
authors.lastname: Davis
authors.forename: Ayalew
authors.initials: A
authors.lastname: Tefferi
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology* / Q000473:pathology; D008218:Lymphocytosis / Q000150:complications* / Q000276:immunology* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D012871:Skin Diseases / Q000209:etiology* / Q000276:immunology* / Q000473:pathology