title: Longitudinal Erythronychia: Retrospective Single-Center Study Evaluating Differential Diagnosis and the Likelihood of Malignancy.
abstract: BACKGROUND
  Longitudinal erythronychia (LE) is an underappreciated and understudied clinical diagnosis. The rates of malignancy and prevalence within the differential diagnosis are not well-established.
  
  
  OBJECTIVE
  To examine the prevalence of biopsy-proven diagnoses in patients presenting with LE.
  
  
  METHODS
  Retrospective single-center study of 65 consecutive patients undergoing biopsy of LE.
  
  
  RESULTS
  Malignancy was identified in only 3 of 65 cases (in situ carcinoma in 2 and melanoma in 1). Onychopapilloma was the most common diagnosis in cases of localized LE. Lichen planus was the most common diagnosis in cases of polydactylous (generalized) LE.
  
  
  CONCLUSIONS
  Longitudinal erythronychia is not a rare clinical finding. The differential diagnosis includes neoplasms, inflammatory conditions, infectious conditions, and scar. Clinicopathologic correlation is required to make the diagnosis in many cases. Malignancy is uncommon, but not rare, with squamous cell carcinoma in situ representing the most common malignancy.
authors.affiliation: *Dermatology Professionals, Inc., East Greenwich, Rhode Island; †Division of Dermatology, University of Massachusetts Medical School, Worcester, Massachusetts; ‡Department of Dermatology, The Warren Alpert Medical School at Brown University, Providence, Rhode Island; §Department of Dermatology, Weill Cornell Medical College, New York, New York.
authors.forename: Nathaniel J
authors.initials: NJ
authors.lastname: Jellinek
authors.forename: Shari R
authors.initials: SR
authors.lastname: Lipner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D002278:Carcinoma in Situ / Q000473:pathology*; D003937:Diagnosis, Differential; D006801:Humans; D008010:Lichen Planus / Q000473:pathology*; D008545:Melanoma / Q000473:pathology*; D008875:Middle Aged; D009260:Nail Diseases / Q000473:pathology*; D010212:Papilloma / Q000473:pathology*; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000473:pathology*