耳介後部に膿瘍を形成した耳輪脚基部先天性耳瘻孔の2例

Two Cases of Fistula Auris Congenita on the Crus Helix with Postauricular Abscess Formation

はじめに

　先天性耳瘻孔は，耳介またはその周辺に見られる小さな瘻孔であり，比較的よく見られる先天性外耳異常の1つである。耳輪前縁部に開口部を有するものが最も多く，次に多いのが耳輪脚基部である。

　今回われわれは，耳輪脚基部の先天性耳瘻孔に感染を来たし，瘻孔の周囲ではなく耳介後部に膿瘍形成を認めた2症例を経験した。耳輪脚基部先天性耳瘻孔に感染を来たし，耳介後部に膿瘍形成することは比較的まれであり，その病態について考察し報告する。

　The common congenital anomaly known as ʻfistula auris congenitaʼ is a small pit around the ear. Although the crus helix is one of the common sites for a fistula auris congenita, it is rare that an infection at this site causes a postauricular abscess formation. We have treated two patients with an infected fistula auris congenita that formed a postauricular abscess. We excised each of the fistulas after the infection subsided. Each patientʼs fistula penetrated the auricular cartilage, and we excised the fistulas together with the auricular cartilage. Because of the anatomical features of the auricular cartilage, a fistula auris congenita on the crus helix often penetrates the auricular cartilage, and if it is infected, a postauricular abscess may be formed. When clinicians encounter a postauricular abscess, they should search for the possible existence of a fistula auris congenita on the crus helix.