Chondroma in the bony external ear canal. (Otoscopic Clinic).

The otoscopic photograph shows a chondroma in the left bony external ear canal. The white mass at the medial portion of the anterior wall of the left bony external ear canal was found incidentally in a 37-year-old woman during a routine examination. The woman had not complained of any ear symptoms. Under local anesthesia, the tumor was carefully excised with the aid of otomicroscopic magnification. Histopathologic examination of the excised tumor identified a chondroma that was made up of mature hyaline cartilage.

To the author's knowledge, only 14 cases of chondroma of the bony external ear canal have been documented in the literature. (1) All but one of these cases had occurred at the medial portion of the anterior wall of the bony external ear canal in front of the short process of the malleus. The one exception was a case in which the tumor was located at the posterior wail of the bony external ear canal. (2) These reported tumors were usually solitary, hard, white masses that had a homed or clubbed shape and a smooth surface. Their diameter usually ranged from 2 to 4 mm. The differential diagnosis includes keratoma, exostosis, osteoma, and fibroma.

The etiology of this benign tumor remains unknown. It is assumed that it originates in the ectopic cartilaginous embryonic rests of Meckel's cartilage of the first branchial arch. Recommended treatment of bothersome masses is complete surgical resection. Asymptomatic tumors can be simply observed.

References

(1.) Lee FP, Chou PZ. Chondroma of the bony external auditory canal. Otolaryngol Head Neck Surg 2001;125:406-7.

(2.) Johnson IJ, Tadpatrikar MH, Sharp JF. Chondroma of the external auditory canal. J Laryngol Otol 1998;112:278-9.