Spontaneous regression of an epidermoid cyst in a pediatric patient-Case report and review of the literature.

Epidermoid cysts are infrequent, benign, slow-growing, space-occupying lesions that account for 0.5-1.8% of primary intracranial tumors. We report the case of a 17-month-old child who presented in 2015 for one episode of pallor associated with hypotonia. Epilepsy was excluded and MRI was recommended. The MRI was performed and there were no focal parenchymal lesions, but it showed an extra-axial ovoid lesion with imaging characteristics consistent with epidermoid cyst. Follow-up MRI at one year was performed and it showed minimal increased in dimensions of the cyst, without changes into the signal of the lesion. Another MRI was performed 7 years after and it showed complete resolution of the cyst. Six months afterwards, another MRI was performed and it confirmed the complete regression of the cyst, without any extra-axial masses reported. The patient did not present any neurological anomalies. No follow-up MRI was recommended afterwards. Spontaneous regression of epidermoid cyst in pediatric population is an extremely rare event, but it should be taken into account when the patient shows no symptoms. This is the third case of spontaneous regression of an epidermoid cyst reported in pediatric patients, and the first one in the temporal region. Careful follow-up and watchful waiting could be an option to surgical treatment in epidermoid cysts.