Salivary gland choristoma of the middle ear: case treated with KTP laser

Abstract

Salivary gland choristoma of the middle ear is rare. It consists of non-malignant, non-growing, normal salivary gland tissue in the middle ear. It is a developmental abnormality that occurs around the proximal part of the second branchial arch before the fourth month of intrauterine life.

The authors found the 25th recorded case in our centre and another 24 reported cases from a review of the literature between 1961 and 1999. Intratympanic salivary gland choristoma frequently occurs during the first and second decades of life and with a female preponderance (56 per cent). Nearly all the patients (96 per cent) in our review presented with a hearing loss, that had begun since birth, in infancy, or during childhood. Tinnitus (28 per cent), and serous otitis media (24 per cent) were also commonly present. One case complained of otorrhoea. Intratympanic and extratympanic anomalies were found in 96.2 per cent and 34.6 per cent of cases respectively. Of these anomalies, ossicular chain (88.5 per cent), facial nerve (65.4 per cent), middle-ear muscles (30.8 per cent) and labyrinthine windows (23 per cent) were the four most common sites. Therefore, salivary gland choristoma may represent a manifestation of a congenital ear anomaly.

Diagnosis of salivary gland choristoma is generally not documented pre-operatively, but is based on surgical biopsy and histopathological investigations. Treatment of this rare lesion depends on the size, location and extent of the mass, degree of anatomical abnormality and expertise of the surgeon. In difficult cases where the mass is attached to the dehiscent or inferiorly placed facial nerve, only biopsy is recommended. However, complete surgical removal is advocated for a mass that is easy to remove. KTP laser use via a 200 micron fibreoptic light carrier can facilitate removal especially in cases with ossicular chain involvement.