Congenital isolated midline sinus of the upper lip: clinical and embryological approaches.
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.
Charrier
Jean-Baptiste
JB
Department of ENT and Maxillofacial Surgery, Saint Louis Hospital, Paris, France. jeanbaptiste_charrier@hotmail.fr
Rouillon
Isabelle
I
Roger
Gilles
G
Denoyelle
Françoise
F
Collon
Sylvie
S
Garabedian
Eréa Noël
EN
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