[L. laesio, a wound]

1. A circumscribed area of altered or diseased tissue.
2. An injury or wound.
3. A single infected patch in a skin disease.
Primary or initial lesions include macules, vesicles, blebs or bullae, chancres, pustules, papules, tubercles, wheals, and tumors. Secondary lesions are the result of primary lesions. They may be crusts, excoriations, fissures, pigmentations, scales, scars, and ulcers.

4. To form or make a lesion.

anal squamous intraepithelial lesion

ABBR: ASIL SEE: Anal intraepithelial neoplasia.

Bankart lesion

SEE: Bankart lesion

coin lesion

SEE: Solitary pulmonary nodule.

degenerative lesion

A lesion caused by or showing degeneration.

destructive lesion

A pathological change such as an infection, tumor, or injury that causes the death of tissue or an organ.

Dieulafoy lesion

SEE: Dieulafoy, Georges

diffuse lesion

A lesion spreading over a large area.

discharging lesion

1. A brain lesion that discharges nervous impulses.
2. A lesion that discharges an exudate.

focal lesion

A lesion of a small definite area.

gross lesion

A lesion visible to the eye without the aid of a microscope.

high-grade squamous intraepithelial lesion

ABBR: HGSIL A premalignant squamous lesion, found on the Papanicolaou test, which may be moderate dysplasia, severe dysplasia, or carcinoma in situ.

Treatment requires removal or destruction of the affected cells, usually with loop electrosurgical excision procedure (LEEP) or ablation. Left untreated, HGSIL may progress to invasive cervical cancer.

Hill-Sachs lesion

SEE: Hill-Sachs lesion

indiscriminate lesion

A lesion affecting separate systems of the body.

initial lesion of syphilis

A hard chancre.
SEE: chancre; SEE: syphilis

irritative lesion

A lesion that stimulates or excites activity in the part of the body where it is situated.

Janeway lesion

SEE: Janeway lesion

local lesion

A lesion of nervous system origin giving rise to local symptoms.

lower motor neuron lesion

An injury occurring in the anterior horn cells, nerve roots, or peripheral nervous system that results in diminished reflexes, flaccid paralysis, and atrophy of muscles.

low-grade squamous intraepithelial lesion

ABBR: LGSIL A cytological abnormality found in Papanicolaou tests (Pap tests) where there are early mild changes in the epithelial cells covering the outside of the cervix. Causes include infection with human papillomavirus, cervical trauma, or postmenopausal changes. Risk factors include intercourse with multiple sex partners or a partner with multiple sex partners, unprotected sex at a young age, history of sexually transmitted disease, and tobacco use. About 60% of LGSIL will spontaneously resolve. If left untreated, a small number of women eventually develop cervical cancer.

molecular lesion

SEE: Molecular disease.

peripheral lesion

A lesion of the nerve endings.

primary lesion

The first lesion of a disease, esp. used in referring to chancre of syphilis.

Quilty lesion

SEE: Quilty lesion

reverse Hill-Sachs lesion

SEE: reverseHill-Sachs lesion

rimmed lesion

A lesion with an identifiable border that contrasts with the substance it encloses, e.g., a lesion with a surrounding tissue layer or radiographic margin.

SLAP lesion

A front-to-back tear of the upper rim of the glenoid labrum where the biceps tendon anchors to the labrum. Common causes include falling on an outstretched hand; forceful, heavy lifting, and repeated overhead motion, e.g., throwing overhand. SLAP is an acronym of superior labral (tear) from anterior to posterior.

space-occupying lesion

A lesion that has a definite volume and may encroach on nearby structures.
SEE: mass (1)

storage lesion

In blood banking and transfusion therapy, the biochemical and structural degradation of blood cells that occurs over time.

structural lesion

A lesion that causes a change in tissue.

systemic lesion

A lesion confined to organs of common function.

toxic lesion

A lesion resulting from poisons or toxins from microorganisms.

upper motor neuron lesion

Neurological damage to the corticospinal or pyramidal tract in the brain or spinal cord. This lesion results in hemiplegia, paraplegia, or quadriplegia, depending on its location and extent. Clinical signs include loss of voluntary movement, spasticity, sensory loss, and pathological reflexes.

vascular lesion

A lesion of a blood vessel.