title: Congenital isolated midline sinus of the upper lip: clinical and embryological approaches.
abstract: OBJECTIVE
  Congenital sinuses or fistulas of the lip are uncommon malformations, yet true medial upper-lip fistulas (MULFs) are extremely rare. We present a new case of congenital upper-lip fistula located in the midline of the philtrum of an 8-month-old girl.
  
  
  METHODS
  Complete surgical removal was performed with a combined extra- and intraoral approach. Histological examination revealed that the fistula was lined by squamous epithelium with sebaceous and mucous glands and hair follicles.
  
  
  RESULTS
  Several embryological hypotheses have been proposed concerning these anomalies. This article reexamines and discusses major embryological theories on pathogenesis of sinuses or fistulas of the upper lip. We propose that early ectodermal inclusion events may occur in the medial fusion area during formation of the intermaxillary process. This embryological approach is highly concordant with our recent hypothesis on nasal dermoid sinus cysts (NDSCs) pathogenesis, in which we proposed an embryological hypothesis with early ectodermal inclusion phenomenon in the midline suture area to explain NDSCs pathogenesis.
  
  
  CONCLUSIONS
  Common early ectodermal inclusion phenomena could be involved in both NDSCs and MULFs pathogenesis.
authors.affiliation: Department of ENT and Maxillofacial Surgery, Saint Louis Hospital, Paris, France. jeanbaptiste_charrier@hotmail.fr
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Charrier
authors.forename: Isabelle
authors.initials: I
authors.lastname: Rouillon
authors.forename: Gilles
authors.initials: G
authors.lastname: Roger
authors.forename: Françoise
authors.initials: F
authors.lastname: Denoyelle
authors.forename: Sylvie
authors.initials: S
authors.lastname: Collon
authors.forename: Eréa Noël
authors.initials: EN
authors.lastname: Garabedian
mesh_terms: D017577:Cutaneous Fistula / Q000151:congenital / Q000196:embryology / Q000601:surgery; D004475:Ectoderm / Q000473:pathology; D005260:Female; D006801:Humans; D007223:Infant; D008046:Lip / Q000002:abnormalities* / Q000601:surgery; D016155:Oral Fistula / Q000151:congenital* / Q000196:embryology / Q000601:surgery