Colloid Cyst

John Sauret, MD

After suffering with recurrent, diffuse, daily headaches for 4 months, a 51-year-old woman sought medical advice. She described the headaches as severe and said they were affected by the position of her head, particularly when bending forward. She also reported episodes of transient numbness on her right side. No syncope was noted, and the patient denied nausea and vomiting.

After suffering with recurrent, diffuse, daily headaches for 4 months, a 51-year-old woman sought medical advice. She described the headaches as severe and said they were affected by the position of her head, particularly when bending forward. She also reported episodes of transient numbness on her right side. No syncope was noted, and the patient denied nausea and vomiting. A CT scan of the patient's head revealed a third-ventricle mass (A, arrow) with evidence of obstructive hydrocephalus (B, arrow). An MRI confirmed a third-ventricle mass consistent with a colloid cyst (C, arrow). The patient underwent a craniotomy, and the mass was resected successfully. The pathologic report confirmed the diagnosis of a colloid cyst.

Dr John Sauret of the State University of New York at Buffalo explains that colloid cysts-which account for fewer than 1% of primary brain tumors-are non-neoplastic lesions that arise from the third ventricle. They expand slowly and can grow to 4 cm in diameter. The cysts contain a gelatinous material composed of mucopolysaccharides, proteins, and cerebrospinal fluid.

Colloid cysts are located anteriorly near the foramen of Monro. Blockage of the foramen may lead to acute intermittent hydrocephalus. The symptoms of this condition can be affected by posture or head positioning. Episodes of headache with paresthesias, weakness of the limbs, visual changes, and incontinence are characteristic symptoms of this tumor. Coma and sudden death also have been reported.

This patient's postoperative course was uneventful. She has received physical therapy and can walk without assistance. She remains asymptomatic 3 months after surgery.