title: [Basal cell carcinoma of unusual site].
abstract: BACKGROUND
  Labial mucosa is an atypical site of basal cell carcinoma. The involvement of the vermilion lip, devoid of hair follicles and sweat glands, contrasts with the concept of its origin from pilar structures. We report a case of basal cell carcinoma developed on the vermilion upper lip.
  
  
  METHODS
  A 49-year-old woman, presented with an asymptomatic, 1-cm-diameter, erythematous, telangiectatic and crusted nodule on the upper lip evolving for 9 months and having once interested the vermilion border. There were no cervical lymph nodes. Diagnosis of infiltrative basal cell carcinoma was made by histological study, which showed a tumoral proliferation of epithelial basal cells infiltrating the dermis with perineural and muscular infiltration.
  
  
  CONCLUSIONS
  Our report illustrates a rare but not exceptional site of basal cell carcinoma. The nodule, initially confined to the vermilion border, has then developed onto the mucosal and the cutaneous areas. Histopathological study revealed, as previously reported, infiltarative features. Basal cell carcinoma of the lip should be rapidly managed since its invasion to deeper structures occurs early.
authors.affiliation: Service de dermatologie, hôpital Habib Thameur, Montfleury, Tunis, Tunisie. rym.benmously@rns.tn
authors.forename: Rym Benmously
authors.initials: RB
authors.lastname: Mlika
authors.forename: Nadia
authors.initials: N
authors.lastname: Kerkeni
authors.forename: Amel
authors.initials: A
authors.lastname: Jebali
authors.forename: Mohamed
authors.initials: M
authors.lastname: Zghal
authors.forename: Achraf
authors.initials: A
authors.lastname: Debbiche
authors.forename: Mohamed Ben
authors.initials: MB
authors.lastname: Ayed
authors.forename: Insaf
authors.initials: I
authors.lastname: Mokhtar
authors.forename: Samy
authors.initials: S
authors.lastname: Fenniche
mesh_terms: D002280:Basal Cell Carcinoma / Q000473:pathology*; D020405:Dermis / Q000473:pathology; D004817:Epidermis / Q000473:pathology; D005260:Female; D006801:Humans; D008048:Lip Neoplasms / Q000473:pathology*; D008875:Middle Aged; D009092:Mucous Membrane / Q000473:pathology; D009130:Muscle, Smooth / Q000473:pathology; D009361:Neoplasm Invasiveness; D009412:Nerve Fibers / Q000473:pathology