CMN & Nevus Terms Glossary

 

This guide was designed to help you understand the terminology you may encounter with regard to large/giant congenital nevi (CMN) and neurocutaneous melanocytosis (NCM). It briefly defines in layman’s terms the technical terminology used by doctors and medical professionals. If you have further questions after reviewing this glossary, please contact your doctor or Nevus Outreach.

Biopsy

Removal of a small piece of tissue for microscopic examination for diagnostic purposes.

Brain Regions

A diagram showing the regions of the brain

Cancer

Uncontrolled growth of cells.

Congenital

Present at birth or within the first year of life.

Contrast

A substance, or dye, given in the vein, to enhance the MRI or CT films.

CT Scan (Computed Tomography)

Also called CAT (Computed Axial Tomography) A diagnostic tool for the examination of the body, such as the brain. CT is generally less expensive but less sensitive than MRI in detecting abnormalities.

Cultured Epithelial Autografts

See cultured skin.

Cultured Skin

One limited option of treatment for a nevus. Small sections of the superficial layer (epidermis) of the patient’s normal skin are removed and then allowed to grow in the laboratory. Once they have grown sufficiently large they can be used as thin grafts to cover an excised nevus.

Drain

A tube or wick sometimes inserted during an operation to ensure that any fluid accumulated beneath the skin is immediately removed. Typically inserted within the wound beneath undermined areas or a transposed flap.

EEG (electroencephalogram)

Amplification, recording, and analysis of the activity of the brain. An EEG is helpful in diagnosing seizures and other convulsive disorders.

EMLA™ (Eutectic Mixture of Local Anesthetics)

A cream used to numb the skin before laser treatments.

Excise

To cut away or take out surgically.

Flap

An area of skin and subcutaneous tissue that can be elevated and moved to an adjacent area.

Gadolinium

A dye given in the vein, that is used as a contrast during MRI to help diagnose mass lesions in patients with NCM.

Hair

There are two types of hair:

Vellus

Soft, colorless hair

Terminal

Thick, coarse, colored hair

Hereditary

A condition that may be transmitted from one generation to the next.

Hydrocephalus

Enlargement of the brain ventricles because of increased fluid. Nevus cells inside the central nervous system blocking the circulation of fluid can be the cause.

Incision

A surgical cut.

MRI (Magnetic Resonance Imaging)

A diagnostic tool useful for examining the central nervous system.

Malignant

An uncontrolled growth of cells that can spread throughout the body.

Melanin

The pigment particles that give color to hair, skin and eyes.

Melanocyte

A cell that produces melanin.

Melanoma

A tumor or mole that is malignant.

Melanosis

Proliferations of melanocytes usually resulting in dark pigmentation.

Meninges

The three membranes that envelope the brain and spinal cord, called the dura mater, arachnoid and pia mater. The inner two layers are called the leptomeninges.

Mole

A collection of pigmented cells in the skin.

Neurocutaneous

Existing on both the skin and nervous system.

Nevi

Plural of nevus.

Nevomelanocyte

Cells composing nevi or moles.

Naevus

See nevus.

Nevus

A mole or pigmented birthmark.

Papilledema

Swelling of the optic disk caused by increased pressure within the brain.

Pigment

Any organic coloring matter.

Posterior Axial

Along or covering the spine.

Seizure 

Any sudden and recurring abnormal functioning of the brain. In order of severity, seizures can be classified as:

Focal

Confined to one part of the body. These can generalize and become grand mal seizures.

Petit Mal

Brief absences, no muscle spasms

Grand Mal (also called clonic-tonic)

Unconscious muscle spasms

Serial Excision 

Having several surgeries done over time to remove a large congenital nevus.

Skin

A diagram showing the parts of skin

Epidermis

Upper protective layer of skin

Dermis

“Working” layer of skin, contains hair follicles and other skin structures

Subcutaneous Fat (adipose tissue)

Thin layer of padding, sometimes not found under “nevus skin.”

Skin Graft 

Using healthy skin from one area of the body and to cover a part that has lost its skin. This may be full thickness (including all of the dermis) or split/partial thickness (including only part of the dermis).

Simple Excision 

A single surgical removal.

Tissue (Skin) Expansion 

Expandable bags are placed under the uninvolved skin and slowly inflated with saline. This causes more uninvolved skin to be created and this extra skin can be used to replace part of a nevus removed during a surgical excision, allowing more nevus to be removed.

V-P Shunt (Ventricular-Peritoneal Shunt)

Tube connecting the ventricles of the brain to the abdominal cavity. A passage connecting two anatomical channels and diverting blood or other fluid from one to the other.

 

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