pineoblastoma
Meaning of pineoblastoma: A tumor sitting exactly where it can dam the brain's drainage, so the first sign is pressure rather than anything local.
Definition of pineoblastoma
Pineoblastoma is a fast-growing cancer arising from the cells of the pineal gland, a pea-sized structure near the center of the brain. It belongs among the embryonal tumors, built from primitive cells resembling those of the developing nervous system, and it appears mostly in young children. It readily sheds cells into the fluid surrounding the brain and spinal cord.
Why does it cause pressure so early?
Position. The pineal gland sits immediately beside the narrow channel through which fluid drains from the middle chambers of the brain toward the base of the skull. A mass growing there pinches that channel shut, fluid banks up behind it and pressure inside the skull climbs. The result is headache worst on waking, vomiting, drowsiness and double vision, and in an infant a head that enlarges faster than it should. Pressure backward onto the roof of the brainstem produces a distinctive combination: the eyes cannot look upward, the lids pull back, and the pupils respond poorly to light while still narrowing for close focus.
How does it differ from other tumors in the same place?
| Tumor | Typical behavior |
|---|---|
| Germ cell tumors | The commonest here; some are highly treatable and betray themselves through blood and fluid markers |
| Pineocytoma | Slow growing, mostly in adults, often cured by removal |
| Intermediate pineal tumor | Behavior between the two extremes, hard to predict |
| Pineoblastoma | Aggressive, mostly in children, spreads through the fluid |
Telling them apart matters because the treatments differ completely, which is why a pineal region tumor is worked up with blood and fluid markers as well as with tissue.
Is it linked to anything inherited?
Sometimes. Children born with a fault in the retinoblastoma gene, the same fault that causes eye tumors in both eyes, carry it in every cell of the body, and a small number of them develop a pineal tumor as well. The combination of tumors in both eyes and one in the pineal region was named trilateral retinoblastoma before the shared cause was understood. A second inherited syndrome, involving a gene that processes small regulatory RNA molecules, also raises the risk. Most cases, though, arise with no family pattern at all. Because seeding through the fluid is common by the time this brain tumor is found, assessment covers the whole spine as well as the head.
Also known as
Used in a sentence
Imaging showed a pineoblastoma obstructing cerebrospinal fluid flow.
Good to know
Because cells spread through cerebrospinal fluid early, imaging of the entire spine and examination of the fluid form part of the initial assessment rather than a later step.
Word origin
Where “pineoblastoma” comes from
Pineal comes from the Latin pinea, a pine cone, which the gland resembles; -blastoma joins the Greek blastos, a sprout or germ, with -oma, a tumor.