Recurrent cerebellar abscess secondary to cranial dermal sinus associated with dermoid cyst in children

Background: Posterior fossa dermoid cysts are rare, benign lesions whose diagnosis can be quite challenging because of their slow growth and subsequent paucity of symptoms. We present herein an unusual case of recurrent cerebellar abscesses induced by an adjacent extradural dermoid cyst with a complete occipital dermal sinus. Methods: The authors report the case of a 20-month-old girl who presented with signs of acutely raised intracranial pressure and whose head scans showed a left cerebellar hemisphere abscess associated with obstructive hydrocephalus. The patient was treated initially with an external ventricular drain, followed by burr-hole aspiration of the abscess and long-term antibiotics. Since the cerebellar abscess recurred, a posterior fossa craniotomy was performed and gross total resection of the lesion along with the dermal sinus tract and abscess contents was achieved. Histopathological analysis confirmed a dermoid tumor. Conclusions: The occurrence of recurrent cerebellar abscesses must always rise up the suspicion of an associated dermoid cyst. Neuroradiological scans should be carefully evaluated in search for this lesion. Once the diagnosis is established, radical resection of the cyst, sinus tract and infectious components is the treatment of choice.