Diagnostic and Therapeutic Pitfalls Encountered in a Young Adult Patient with a Symptomatic Chronic Subdural Hematoma Mimicking a Subacute Epidural Hematoma in the Presence of a Galassi Grade III Arachnoid Cyst: Case Report

Background and Clinical Significance: Chronic subdural hematomas (cSDHs) present characteristic imaging findings, making the diagnosis straightforward. In rare cases, arachnoid cysts (ACs) may be associated with their formation. There is still no consensus regarding their treatment; Case Presentation: A young adult male presented with occipital headache. Neurological examination was normal. Laboratory investigations were within physiological limits. A CT scan revealed the presence of a Galassi Grade III temporo-parietal AC accompanied by a parietal epidural hematoma (EDH) on the right side. His medical history was significant for treated hypertension. There was no use of anticoagulants, antiplatelets, or history of trauma. Vascular pathology was excluded by MRA/MRV. He was discharged for home care and was readmitted 10 days later after a repeat CT scan. A brief cognitive assessment with the Mini-Mental State Examination (MMSE) revealed mild cognitive impairment. A burr-hole evacuation was performed, and a drainage catheter was left in place for 24 h. Intraoperative findings were consistent with a chronic subdural hematoma. The patient was discharged with complete resolution of symptoms. A follow-up CT scan performed one month postoperatively confirmed the favorable result. Cognitive functions were normal on follow-up; Conclusions: A SDH may mimic the characteristics of an EDH in the presence of an AC. The most common symptom is cephalalgia. Neurocognitive impairment may occur secondary to elevated intracranial pressure. A burr-hole hematoma evacuation may be sufficient. Further treatment should be considered only in the case of complications associated with ACs.