Imaging description

A five-year-old male presented with left sensorineural hearing loss, bilateral pre-auricular pits, and a draining right neck sinus. Initial audiometry demonstrated bilateral hearing loss. CT of the temporal bones was remarkable for bilateral enlargement of the internal auditory canals, dysmorphic appearance of the cochlea bilaterally, and hypoplasia of the lateral semicircular canals (Fig. 5.1). The imaging appearance, in conjunction with the clinical findings, was suggestive of branchio-oto-renal (BOR) syndrome.

Importance

BOR syndrome is an autosomal dominant disorder occurring in approximately 1:40 000 births, although the true incidence may be difficult to establish because not all affected individuals undergo imaging evaluation. Despite the relatively common presentation, the severity of the syndrome is hard to predict given the variable penetrance. The presence of one or more features of the syndrome should prompt clinical and imaging investigation for associated anomalies.

Typical clinical scenario

BOR patients will typically present in the infant/toddler age group with history of hearing loss and pre-auricular pits. Physical examination may show a long, narrow face, preauricular pits, mis shaped ears, lacrimal duct aplasia or stenosis, high arched or cleft palate, branchial cleft fistula, or clefts. Imaging features have classically been described to include a calcified or shortened anterior malleolar ligament, narrowed malleoincudal joint, ossicular displacement, hypoplastic apical and basal turns of the cochlea, medial deviation of the facial nerve, underdevelopment of the vestibule, enlarged vestibular aqueduct, and funnel-or ellipsoid-shaped internal auditory canal. Renal malformations are common and can be unilateral or bilateral and occur in any combination. Some of the more common anomalies seen on renal ultrasound or intravenous pyelography are renal agenesis (29%), hypoplasia (19%), dysplasia (14%), ureteropelvic junction obstruction (10%), calyceal cyst or diverticulum (10%), and caliectasis, pelviectasis, hydronephrosis, and vesico-ureteral reflux (all at 5%). There are even documented cases of renal dysplasias not presenting until adulthood.