Arachnoid cyst (AC) is a fluid-filled malformation of the arachnoid tissue. 1 Congenital, genetic, and traumatic factors have been suggested as the underlying mechanisms. Prevalence is estimated at 2.6% in children and 1.4% in adults. Symptoms such as headache, epilepsy, cognitive impairment, and dizziness are frequently reported in AC patients. However, AC are frequently discovered incidentally in asymptomatic patients undergoing radiological investigation for various other neurological symptoms. The large majority of AC remain constant in size and a conservative management has been proposed for most of the patients. Although there has been considerable controversy regarding the indications for the surgical treatment of asymptomatic AC, the literature seems to show some consensus that patients with symptomatic AC causing seizures, hydrocephalus, increased intracranial pressure, neurological impairment and those complicated by intracystic or subdural hemorrhage should be treated. 2 Before considering surgery for intractable symptoms attributed to AC, their relationship should be explored in detail and objective criterion should be used. The aim of this case report is to illustrate an unusual cause of symptomatic AC inducing Holmes' tremor (HT) successfully treated with surgery. HT is a low-frequency tremor characterized by a combination of rest, posture, and kinetic components. 3