Glossary

Helpful Links to Find Additional Medical Information:

A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z

M

Macroadenoma: a pituitary adenoma that is greater than 10 mm in maximal diameter. Learn more.
Malignant: a severe and progressively worsening disease; used most frequently to describe a cancer and contrasted with a non-cancerous or “benign” tumor. Most malignancies are capable of invading adjacent tissues and may spread to distant tissues (metastasize).
Mass Effect: local pressure from a tumor or bleeding (hematoma) on adjacent parts of the brain. Mass effect is diagnosed by an MRI or CT scan which shows where the mass is and what it is pushing on. Mass effect can lead to neurological symptoms such as weakness or loss of vision depending upon the location of the tumor or hematoma.
Maxillary Sinus: the largest air sinuses (paranasal sinus) located behind the cheekbones and below the orbits. These paired sinuses drain into the nasal cavity like the ethmoid and sphenoid sinuses.
Meningioma: a typically benign brain tumor although up to 5% can be aggressive or malignant. They are more common in women than men and can occur in all ages but are typically seen in middle-aged and older adults. Meningiomas may arise from any meningeal surface and are typically attached to the dura (outer layer of the meninges). Common locations include the convexity of the calvarium, frontal fossa (olfactory groove), tuberculum sella (near the pituitary gland), sphenoid wing and in other skull base areas. Primary treatment of symptomatic meningiomas is usually by surgical removal, often by a keyhole craniotomy or endonasal approach. Learn more.
Meningitis: inflammation or infection of the protective membranes covering the central nervous system, known collectively as the meninges. Meningitis most often develops from a viral or bacterial infection. While some forms of meningitis are mild and resolve on their own, meningitis is a potentially serious life-threatening condition. Bacterial meningitis can occur after intracranial surgery, especially in association with a leakage of cerebrospinal fluid (CSF leak). Prompt repair of the leak and antibiotics are required treatment. Learn more.
Metastasis & Metastatic Tumor: tumors that arise from a cancer from one organ and spread to a distant site such as the brain (also known as secondary brain tumors). The most frequent types of cancer that metastasize to the brain are lung, breast, melanoma, colon, renal (kidney) and thyroid. Treatment of metastatic brain tumors may involve surgical removal through a craniotomy, radiosurgery (SRS) or whole brain radiotherapy or chemotherapy. In many instances, all 3 of these treatments are needed. Learn more.
Micro-Doppler Probe: this non-invasive device is used during surgery for localizing large arteries and veins (such as the carotid artery) of the brain. Lean more.
Microadenoma: a pituitary adenoma that is less than 10 mm in maximal diameter. Learn more.
Minimally Invasive Surgery: performing surgery through relatively smaller “Keyhole” incisions with less trauma to local tissues allowing for a more rapid and less painful recovery. Learn more.
Moon Face: an abnormal accumulation of fatty padding around the face. Symptoms and signs of Cushing’s syndrome and disease may include: change in body habitus and weight gain in face (moon face) above the collar bone (supraclavicular) and on back of neck (buffalo hump). Lean more.