Introduction and importance:Intracranial dermoid cysts (IDC) are defined as rare, slow-growing cystic congenital neoplasms. Rupture of an intracranial dermoid cyst occurs rarely and most often spontaneously and results in potentially serious symptoms.Case presentation:A39-year-old female, with mechanical prosthetic heart valve presented with history of headache for 10 months and generalized tonicoclonic seizures. On the admission, the patient had a normal neurological and cranial nerve exam. The authors performed a computed tomography of the brain, The MRI could not be performed because of the presence of the prosthetic valve, revealed rupture of the dermoid cyst in the bilateral subarachnoid spaces. The patient underwent a large temporal craniotomy and the tumour was well exposed and completely removed without incident, the histopathological examination concludes to dermoid cyst, the patient recovered well from surgery.Clinical discussion:Rupture is a very rare phenomenon. there are about 60 cases reported in the literature. the contents of the cyst disseminate into the subarachnoid and ventricular spaces in the event of rupture. A variety of clinical symptoms is usually caused. The mechanism of spontaneous rupture of the dermoid cyst is unclear. Among the proposed mechanisms is a rapid expansion of the cyst. Complete surgical resection of dermoid cysts is the only effective treatment for the prevention of recurrences and/or complications.Conclusion:Rupture of an intracranial dermoid cyst is associated with significant morbidity and mortality, although it remains a rare phenomenon. Surgical excision should be considered as soon as the diagnosis is made in order to prevent more severe intracranial complication.