Unusual anomaly of the external ear

Ear, Nose & Throat Journal, August, 2004 by John R. LaFrentz

A 1-month-old white, female infant was referred to the otolaryngology service because of the unusual appearance of her left auricle. She was delivered by cesarean section at term after an attempt at vaginal delivery, following an uncomplicated pregnancy. The mother used acetaminophen sparingly during pregnancy and 1% hydrocortisone cream briefly in the third trimester. There was no family history of congenital anomalies.

Examination revealed a normal-appearing right external ear, external auditory canal, and tympanic membrane. The left ear demonstrated an unusual anomaly in which a prominent helical crus fused with the midportion of the antihelix, pinching the meatus (figure). Medial to the meatus, the external auditory canal and tympanic membrane were of normal caliber. The infant passed screening otoacoustic emissions bilaterally. The neck examination was devoid of pits, cysts, sinuses, and fistulas; there was no palatal cleft.

[FIGURE OMITTED]

Morphology of the external ear follows ontogeny and embryology of the 6 hillocks of His. The first 3 tubercles are first branchial arch derivatives and form the (1) tragus, (2) helical crus, and (3) helix. Tubercles 4 through 6 arise from the second branchial arch and form the (4) antihelix, (5) antitragus, and (6) lobule. Between 6 and 12 weeks of gestation, the hillocks form and fuse, and by 20 weeks, the auricle takes on its usual appearance.

This unusual anomaly, with the helical crus bridging the concha to unite with the antihelix, represents a malformation of the first and second branchial arch derivatives. Similarly, Fischl in 1976 described a third crus of the antihelix and a prominent crus of the helix. (2) Union of the inferior crus to the helix, as well as to the convex conchac, has been reported. (3,4) Anomalies has been described with the maternal use of tretinoin cream, (5) but no external causative factors are readily apparent in this case. As in the case of prominent ears, surgical correction, if desired, should be delayed until the child is school age, to prevent interruption of auricular growth.

References

(1.) Lee KJ, ed. Essential Otolaryngology. 7th ed. Stamford: Appleton and Lange, 1999:11-12.

(2.) Fischl RA. The third crus of the antihelix and another anomaly of the external ear. Plast Reconstr Surg 1976;58:192-5.

(3.) Kayikcioglu H, Tuncali D, Safak T. An unusual anomaly of the antihelix. Plast Reconstr Surg 1998;102:578-9.

(4.) Yii NW, Walker CC. Unusual conchal deformity in otherwise normal ears. Plast Reconstr Surg 1996;98:726-9.

(5.) Camera G, Pregliasco P. Ear malformation in a baby born to mother using tretinoin cream. Lancet 1992;339:687.