Radiological and pathological findings in three cases of childhood pineocytomas.

The radiological and pathological findings in three children with pineocytomas are described. The patients presented with symptoms and signs of increased intracranial pressure. CT scans demonstrated obstructive hydrocephalus, but failed to visualize pineal masses that were subsequently seen on MR scans. A suboccipital, supracerebellar approach was used to obtain tissue for histological diagnosis and, in one case, achieve a total removal. Light microscopy demonstrated typical pineocytomatous rosettes without evidence of gangliocytic or astrocytic differentiation. Electron microscopy revealed numerous dense core vesicles with synaptic ribbons, suggesting neurosecretory capability. These three cases demonstrate the diagnostic advantage of MR imaging for tumors in the pineal region as well as the relatively well-differentiated histopathological characteristics of pineocytomas.