Concomitant chronic subdural hematomas and arachnoid cysts in young adults

Objective: This study aimed to evaluate the correlation between arachnoid cysts and chronic subdural hematomas in young adults. Methods: This retrospective study evaluated ten patients having concomitant chronic subdural hematomas and arachnoid cysts. Patients were evaluated with the data of age and gender, location of hematoma and arachnoid cyst, trauma history, symptoms at admission, maximum hematoma diameter, contiguity between arachnoid cyst and hematoma, and treatment  methods. Results: We treated 285 patients who were diagnosed with cSDH between January 2013 and December 2019. 22 patients were under the age of 40 years. Ten of them had both cSDH and arachnoid cysts. The mean age of patients was 24.8±3.9 years. Patients with only chronic subdural hematoma had higher mean age than the patients with arachnoid cyst-related chronic subdural hematoma. In four patients, the onset of chronic subdural hematoma was reported after arachnoid cyst diagnosis. Four of the patients did not have causative trauma history, and two patients suffered minor sports-related traumas. All patients had headache, and only two patients had hemiparesis. The location of arachnoid cysts were in the middle fossa in eight patients. All patients had chronic subdural hematomas on the ipsilateral side of arachnoid cyst. Four patients who had smaller than 10 mm maximal cSDH diameter underwent conservative management. They were followed by serial neuroimaging studies and it was noted that the hematoma disappered and the size of the arachnoid cysts decreased over time without any neurological complication. In six cases, craniotomy was required, and all recovered completely. cSDH did not recur during 5-60 months of follow-up period (median 12 months). Conclusions: It seems that presence of an arachnoid cyst in young adults is a predisposing factor for the formation of chronic subdural hematoma. Coincidentally diagnosed arachnoid cyst patients may be followed up with periodical clinical examinations and neuroimaging studies.