Infected colloid cyst

Introduction Colloid cysts are the most common pathologic lesions of the third ventricle. Although they are histologically benign, they may grow and can cause the hydrocephalus. Case summary A 5-year-old male patient underwent to surgery with the diagnosis of colloid cyst. In operation, after the anterior transcallosal approach, the cyst was punctured by syringe and obviously pus aspirated. Conclusion Colloid cysts mostly remain silent and detected incidentally. Although it is rarely defined, rhinorrhea, hypopituitarism, diabetes insipidus, spasmodic torticollis, drop attack, aseptic meningitis, and coexistence with neurocysticercosis have been reported, but this is the first reported case of an infected colloid cyst.