‘Honeycomb’ tegmen: multiple tegmen defects associated with superior semicircular canal dehiscence

To report the coexistence of multiple tegmen defects, forming a 'honeycomb' pattern, together with dehiscence of the superior semicircular canal. We describe three cases in which the above findings were noted, and we review the relevant literature. Superior semicircular canal dehiscence is defined as the absence of portions of bone over the canal along the floor of the middle fossa. Most published articles describe the defect as an isolated finding which is either unilateral or bilateral. Studies on temporal bones show either a defect over the superior semicircular canal or isolated defects over the tegmen. We describe three cases in which we found multiple tegmen defects, giving a characteristic honeycomb appearance, coexisting with dehiscence over the superior semicircular canal. This finding, which supports the theory of a developmental defect as the origin of the condition, has not previously been reported. A literature review is presented, with discussion of the aetiology and management of superior semicircular canal dehiscence.