2019 年 65 巻 7 号 p. 474-478
Congenital commissural lip fistula is caused by non-fusion in the embryonic phase. Cases accompanied by inflammatory symptoms or requiring surgery are rare. Van der Woude Syndrome (VWS) has been reported to be a syndrome where commissural lip fistula is present and autosomal dominant.
The patient was a 1-year 7-month-old boy who was examined in our department upon request for further evaluation of a mass in the left cheek. Initial examination showed a quail-egg-sized elastic, soft mass. Five months later, infection was found in the mass. Inflammation was treated, and excision through the oral cavity was planned. During surgery, a continual fistula-like structure was found in the left corner of the mouth. The structure was confirmed to be a commissural lip fistula and was removed. Currently, 1 year 6 months after surgery, the patient has made favorable progress, with no abnormal findings.
Commissural lip fistula should be included in the differential diagnosis when the cause of lesions near the corners of the mouth cannot be determined.