The authors report an unusual case of a 2-year-old boy with a 3-month history of 
episodic rightward anterolateral head tilt and large-amplitude positional 
anteroposterior head bobbing reminiscent of bobble-head doll syndrome. This 
child experienced a sudden onset of drop attacks and then, within several hours, 
deep coma. The causative lesion was a contrast-enhancing, partially cystic third 
ventricular mass, which ultimately obstructed the aqueduct, producing profound 
obstructive hydrocephalus. An emergency ventriculostomy and endoscopic 
fenestration of the septum pellucidum was performed. Four days later, the tumor 
was completely resected by a transcallosal-transforaminal approach. The lesion 
was freely mobile within the third ventricle and contained a large cyst within 
its posterior pole; following drainage of the cyst, the lesion was easily 
delivered through the foramen of Monro. The histopathological diagnosis was 
choroid plexus papilloma. The child's neurological deficits, head tilt, and head 
bobbing resolved immediately after operation. To the best of the authors' 
knowledge, this represents the first well-documented report of bobble-head doll 
syndrome and drop attacks secondary to a choroid plexus papilloma. The highly 
mobile nature of the cystic lesion presumably led to its intermittent impaction 
within the foramen of Monro and/or proximal aqueduct; this produced the 
intermittent head tilt and bobble-head symptoms and, ultimately, resulted in 
acute obstruction of the aqueduct, causing the child's precipitous neurological 
decline.