Introduction: Cranial dermal sinus, usually associated with dermoid cyst, is defined as the abnormal communication between the skin surface and the central nervous system. The cyst results from inclusion of ectodermal elements within the neural tube during its embryonic development [1,2]. Intracranial dermoid cyst accounting only for 0.1-0.7% of all intracranial lesions, the most common location is the posterior fossa near the midline [3]. Cerebellar abscesses or hydrocephalus as the principal manifestations of posterior fossa dermoid cyst are rarely reported [4,5].

Methods: The authors report on the rare cases of posterior fossa abscesses secondary to dermal sinus associated with dermoid cyst in 2 pediatric cases. Two cases of little girls (8 months and 4 years old) having dermal sinus with dermoid cyst manifested by cerebellar abscess formations, with secondary hydrocephalus in one case, are reported. Both pediatric patients underwent the posterior fossa surgery with subsequent antibiotic therapy. In the first case external ventricular drainage was performed before dermal sinus and dermoid cyst operative removal.

Case 1: 8-months old girls admitted for fever, with signs of intracranial hypertension and sixth cranial nerve paresis. Cranial dermal sinus with dermoid cyst, posterior fossa multiple abscesses and secondary hydrocephalus were diagnosed by CT and MRI. External ventricular drainage, antibiotics therapy and subsequent neurosurgical operation was performed with dermal sinus excision and dermoidal cyst and abscesses total exstirpation. Ventricular drainage was removed on the seventh day after surgery. The postoperative course was favourable without any complication, n. abducens paresis persisted.

Case 2: 4-years old girl treated for „atheroma“ by surgeon practicioner. Admitted with cephalgia, fever and vomitus. Occipital dermal sinus with cerebellar abscesses were diagnosed by CT and MRI, and high doses antibiotics therapy was provided. Neurosurgery treatment followed, with excellent result and full recovery.

Results: Six months after the surgery both pediatric patients had normal psychomotor development. The first patient suffered from persistent abducens nerve paresis. The second patient have no focal neurological symptoms.

Conclusion: Posterior fossa dermoid cyst should be considered in pediatric patients suffering from congenital occipital skin lesions [4]. MRI or CT 3D should be performed in case of head localized cutaneous or subcutaneous pathology before surgery treatment. Surgery with total dermal sinus and dermoid cyst eradication should be preferred, even if preceeded by simple abscess drainage and followed by antibiotic therapy. Early dermoid cyst detection has a prognostic value by enabling early neurosurgical treatment to avoid abscess development.

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