1. Background and Importance
rachnoid cysts are rare intra-arachnoid collections of Cerebrospinal Fluid (CSF) that are usually congenital [1]. Many of these mass lesions are asymptomatic but can present with increased Intracranial Pressure (ICP), intracystic hemorrhage and subdural hematoma/hygroma [2]. Most of them are located in the supratentorial region in middle cranial fossa and less frequently in cerebral convexities, cerebellopontine angle, cisterna magna, suprasellar and quadrigeminal cisterns. Suprasellar Arachnoid Cysts (SSACs) are rare. They constitute 10% of all arachnoid cysts and can occlude the aqueduct and third ventricle and result in hydrocephalus [3, 4]. A rare presentation of arachnoid cysts is subdural hygroma. In this study, we present a patient with a suprasellar arachnoid cyst that became complicated with subdural hygroma.
2. Case Presentation
A 25-year-old man was referred to Loghman Hakim Hospital, Tehran, with a chief complaint of headache, nausea, vomiting and right hemiparesis. The early symptoms had begun 1 month earlier after minor trauma in which the patient had undergone burr hole twice due to recurrent left subdural effusion then he was discharged. The signs and symptoms recurred again after discharge which made him refer to our center. Previous medical and family history was unremarkable. In physical examination, he had an orientation to time, place and person. The neurological examination revealed right hemiparesis. The brain Magnetic Resonance Imaging (MRI) showed the suprasellar cyst lesion causing stretching and anterior compression of the midbrain, pons, and optic chiasm with superior extension to the third ventricle with an associated left subdural hematoma, with the compression effect on the ventricles (Figure 1). The patient underwent left craniotomy with pterional approach, subdural effusion was evacuated then the arachnoid cyst was fenestrated to adjacent cisterna basalis. All of the signs and symptoms improved after surgery and in follow-up visits after discharge. 

3. Discussion and Conclusion 
Arachnoid cysts are usually asymptomatic, and many of these cysts are detected incidentally in the brain CT and MRI. The typical presentations are obstructive hydrocephalus, increased intracranial pressure and visual changes, endocrine abnormalities and head bobbing [5, 6]. These cysts are rarely complicated with subdural hematoma/hygroma, and intracystic hemorrhage [7]. SSACs are rare and they comprise 2% of all cysts, usually reported in the pediatric population [8, 9]. They can cause hydrocephalus and lower cranial nerve impairment and endocrine disorder including amenorrhea, precocious puberty, developmental delay and growth retardation [6]. Fahad et al. reported a case that presented with precocious true puberty. The neurological deficit also can arise from the compression of adjacent structures [10, 11]. The exact pathogenesis of subdural hematoma has not been detected so far. Moreover, trauma may have a role in the formation of subdural hygroma and increased intracranial pressure as well as in compression of adjacent structure [12]. There are various treatments for the SSAC including craniotomy and open fenestration and endoscopic technique for establishing normal CSF flow by communication between the arachnoid cyst and intraventricular or subarachnoid space [13]. Our patient had supracerebellar cyst that complicated with subdural hygroma and increased intracranial pressure. He was treated surgically.
Acknowledgments
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Conflict of Interest
The authors declare that they have no conflicts of interest. Authors’ contribution is as follows: Conception and Design: All authors; Data Collection: Karim Moradian-Kokhda; Drafting the Article: All authors; Critically Revising the Article:  All authors; Reviewing Submitted Version of Manuscript: All authors; and Approving the Final Version of the Manuscript: All Authors.


References