Introduction Periocular dermoid cysts are common and leakage of the lipid or keratin contents leads to an inflammation¾often asymptomatic¾around the cyst, which may cause adherence of the dermoid cyst to neighbouring structures. Purpose To investigate the frequency of clinical and radiological signs of inflammation with periocular dermoid cysts, to relate this to the histopathological examination of the excised specimens, and to assess whether the degree of inflammation is related to age at presentation. Patients and Methods A retrospective non-comparative series of 124 patients with periocular dermoid cysts that had undergone imaging. Case-notes were reviewed for clinical and histopathological details and there was independent review of the radiological imaging. Results Surgery was undertaken at between 1 and 66 years of age, most patients being under 10 years, and the duration of symptoms varied from 4 weeks to 30 years. Symptoms of inflammation¾mainly intermittent lid swelling with localised redness and pain¾occurred in all age groups, the proportion being greatest in the fourth decade. Clinical signs of inflammation at the time of clinic visit were relatively few, although 8% had some localised erythema and 7% had tenderness at the site of lesion. In more than two-thirds of the excised cysts, pathological examination demonstrated various degrees of chronic inflammation, even in those cysts removed before the age of 5 years. Conclusion Even if the patient does not have symptoms or signs of inflammation, most periocular dermoid cysts show histological evidence of inflammation due to leakage of the lipid and keratin contents from the cyst, the incidence being similar at all ages. Eye (2002) 16, 507-512. doi:10.1038/sj.eye.6700045 | 
