title: Hobnail hemangioma reclassified as superficial lymphatic malformation: a study of 52 cases.
abstract: BACKGROUND
  Hobnail hemangioma (HH) is currently classified as a benign vascular tumor, although it is not well understood whether this lesion differentiates toward blood or lymphatic endothelial cells. Immunostaining with the endothelial marker Wilms tumor 1 (WT1) helps distinguish between vascular neoplasms and malformations, being positive in the former and negative in the latter.
  
  
  OBJECTIVE
  We sought to investigate WT1, human herpesvirus 8 latent nuclear antigen, D2-40, and Ki-67 immunoprofile in HH, to gain further insight into its histogenesis.
  
  
  METHODS
  We evaluated 52 HHs collected in Dermatohistopathologische Gemeinschaftslabor, Friedrichshafen, Germany. Immunohistochemical expression of WT1 was performed in all cases. Ten of 52 lesions were also studied for D2-40 and Ki-67 staining and 12 lesions were stained for human herpesvirus 8 latent nuclear antigen.
  
  
  RESULTS
  All 52 HHs were completely negative for WT1 immunostaining. Immunohistochemistry performed in 10 HHs showed diffuse and strong positive staining for D2-40 in 8 lesions and focal positivity in two. All cases tested showed negative staining for Ki-67 and human herpesvirus 8 latent nuclear antigen.
  
  
  CONCLUSIONS
  There are no limitations.
  
  
  CONCLUSIONS
  Although the exact histogenesis of HH is unknown, most of the performed immunohistochemical studies support a lymphatic line of differentiation. However, on the basis of the WT1 negativity, we believe that HH is better considered as a lymphatic malformation rather than a lymphatic neoplasm.
authors.affiliation: Department of Dermatology, Hospital de Cascais Dr José de Almeida, Lisbon, Portugal.
authors.forename: Felicidade
authors.initials: F
authors.lastname: Trindade
authors.forename: Heinz
authors.initials: H
authors.lastname: Kutzner
authors.forename: Óscar
authors.initials: Ó
authors.lastname: Tellechea
authors.forename: Luis
authors.initials: L
authors.lastname: Requena
authors.forename: Isabel
authors.initials: I
authors.lastname: Colmenero
mesh_terms: D000911:Antibodies, Monoclonal; D042783:Endothelial Cells / Q000473:pathology; D016162:Genes, Wilms Tumor; D006391:Hemangioma / Q000145:classification / Q000235:genetics / Q000473:pathology* / Q000821:virology; D019288:Herpesvirus 8, Human / Q000302:isolation & purification; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D044148:Lymphatic Abnormalities / Q000145:classification / Q000235:genetics / Q000473:pathology* / Q000821:virology; D009687:Nuclear Proteins / Q000032:analysis; D010750:Phosphoproteins / Q000032:analysis; D012878:Skin Neoplasms / Q000145:classification / Q000235:genetics / Q000473:pathology* / Q000821:virology
chemical_list: D000911:Antibodies, Monoclonal; D019394:Ki-67 Antigen; D009687:Nuclear Proteins; D010750:Phosphoproteins; C118485:latent nuclear antigen (LNA)