Dictionary

pineocytoma See pinealoma.

pineoblastoma A fast-growing brain tumor in the pineal gland that originates in neuroepithelial cells. This malignancy is considered by many to be one of the primitive neuroectodermal tumors (PNETs). Also known as pinealoblastoma.

pinealoma An uncommon slow-growing tumor of the pineal gland. Also known as a pinealocytoma and pineocytoma.

pinealocytoma See pinealoma.

pinealoblastoma See pineoblastoma.

pineal region tumor A brain tumor on or near the pineal gland. There are multiple types of pineal gland tumors, most of which are not cancerous but can nonetheless cause extreme distress. Diagnosis is made via biopsy of affected tissue. Benign pineal tumors are treated with surgery; malignant tumors may be treated with surgery, radiation…

pineal gland A small gland that is located near the center of the brain. This gland secretes melatonin, and it may therefore be part of the body’s sleep-regulation apparatus. Also known as pineal body.

pimple An inflamed area of the skin with pus formation that results from an oil gland being infected with bacteria. Pimples are due to overactivity of the oil glands located at the base of the hair follicles, especially on the face, back, chest, and shoulders.

pilonidal cyst An abscess that occurs in the cleft between the buttocks at the base of the tailbone (coccyx). Pilonidal cysts are common in adolescence, often after long trips that involve sitting.

piloerection Erection of the hair of the skin due to contraction of the tiny arrectores pilorum muscles that elevate the hair follicles above the rest of the skin and move the hair vertically, so the hair seems to “stand on end.”

pill, the See oral contraceptive.

piles See hemorrhoids.