1

Introduction

External auditory canal cholesteatoma (EACC) is rare, with an incidence of 1:1000 of new patients’ visit otologic clinic . Primary epidermoid cyst, which is known as a congenital cholesteatoma, occurs in several sites of the temporal bone. From the previous reports , between 41% and 62% of the EACC cases were primary. Early report as an accumulation of epithelial debris in the external auditory canal (EAC) was made in 1850 by Toynbee . In 1922, Cushing reintroduced the concept of the congenital cholesteatoma. In 1989, Parisier recognized 24% of all cholesteatomas occurring in patients younger than 18 years to be of congenital origin.

In EACC, there are excessive accumulation of keratin material in the canal and osteonecrosis with the focal sequestrated bone without an epithelial covering. At the inferior or posteroinferior part of the bony EAC, just lateral to the intact tympanic membrane, bony erosion is present. Treatment consists of the resolution of granulation and removal of debris. Usually, canalplasty or obliteration of the defect are inevitable. The necrotic bone and matrix must be removed. Long-term follow-up after surgery should be carried out to detect relapses.

There is only one case report of congenital EACC without aural stenosis. Further studies are still required to elucidate in detail the clinical features, cause, and epidemiology of congenital EACC.

2

Case report

A 2-year-old female child with a white mass in the right auditory canal was referred to our hospital. In the physical examination, a white mass occupied the inferior portion of the canal ( Fig. 1 ). In computed tomography (CT) of the temporal bone, a low-density 0.6-cm-sized soft tissue density cystic lesion was located at the floor of the right EAC, in contact with a tympanic membrane ( Figs. 2, 3 ). Mass excision and canalplasty were performed. A postauricular approach was used to elevate the inferoposterior meatal skin exposing the mass in the ear canal. Squamous debris and a cholesteatoma sac were removed carefully, and the irregular eroded bone was saucerized by diamond drill until normal healthy bone was found. A temporalis fascia graft was used to cover the exposed bone before repositioning the meatal skin. The ear canal was packed with gel foam soaked with antibiotics. Pathologic examination confirmed the diagnosis of EACC ( Fig. 4 ).

A white round mass (white arrow) with contact of tympanic membrane (black arrow) is seen at the right external auditory canal of 2-year-old female child.

The CT axial section of the temporal bone, soft tissue window settings. Note the soft tissue density mass at the right external auditory canal.

The CT coronal section of the temporal bone, soft tissue window settings. The soft tissue density mass lesion is seen in the floor of the right external auditory canal.

Pathologic findings of the cystic mass is compatible with congenital cholesteatoma showing a squamous epithelium-lined cyst that is filled with fully differentiated, anucleated, laminated masses of keratinous material (A, hematoxylin and eosin, ×10; B, hematoxylin and eosin, ×40; C, hematoxylin and eosin, ×100).

The patient is being observed until 3 months without any recurrence. Three years later, the recurred EACC was observed. Reoperation was performed as the same manner of the previous operation and was finished successfully without any problem.