Lesions

Lesions are localized abnormalities of tissue that arise from injury, disease, or other pathologic processes. They can affect the skin or internal organs and reflect changes in cells, tissue integrity, blood supply, or inflammation. Lesions are described by location, size, shape, borders, depth, and whether they are solid, fluid-filled, or necrotic. They may be acute or chronic and benign or malignant.

Classification is broad. By location: cutaneous versus internal. By morphology: masses, plaques, ulcers, erosions, vesicles, pustules, cysts. By etiology: traumatic, infectious, inflammatory, autoimmune, ischemic, or neoplastic.

Common cutaneous lesions include macules, papules, vesicles, bullae, plaques, crusts, ulcers, and scars. Internal lesions include infarcts, necrosis, cysts, abscesses, hematomas, tumors, and edema.

Diagnosis combines history and examination with imaging (ultrasound, X-ray, CT, MRI) and laboratory tests. Biopsy with histology is often required to determine cause and differentiate benign from malignant processes.

Management depends on the cause and may include observation, drainage or excision, wound care, antibiotics or antivirals, antifungals, anti-inflammatory therapy, and treatment of the underlying condition.

Prognosis varies with lesion type and response to treatment; benign lesions may remain stable, while malignant lesions require timely intervention.