Paroxysmal Lower Limb Tremor as a Rare Presentation of Colloid Cyst of the Third Ventricle: A Case Report and Literature Review

Colloid cysts of the third ventricle are benign intracranial tumors. They are most commonly presented with signs of intracranial hypertension due to obstructive hydrocephalus, including headache, nausea/vomiting and vision disturbances, whereas extrapyramidal symptoms such as tremor are very rare. Sudden death, due to abruptly developed hydrocephalus, can be also observed. Although paroxysmal symptomatology attributed to the intermittent obstruction of the foramen of Monro is considered the “classical” clinical presentation, it is rather the exception in clinical practice.

A 42-year-old woman with no medical history was admitted to the neurology department as suffering from a potential demyelinating disease due to episodes of paroxysmal tremor of her right lower limb and persistent mild gait instability, which presented 15 days prior to her arrival. She also complained of episodes of partially position-dependent bilateral headache over the last 10 years, as well as episodes of vertigo over the last 4 years. On arrival, her gait was shuffling and mildly wide-based and an intermittent tremor of her right lower limb was observed in supine and sitting positions, but not in a prone position. Brain magnetic resonance imaging (MRI) demonstrated a round cystic lesion of the third ventricle, accompanied by hydrocephalus with enlargement of lateral ventricles. MRI findings were highly indicative of a colloid cyst. The patient underwent resection of the mass and the tremor resolved after surgery.

Given the greatly heterogeneous clinical presentation of colloid cysts, our case highlights the significance of the prompt diagnosis of this rare but potentially fatal cause of paroxysmal limb tremor.