Läsion

A lesion is any abnormality of body tissue that can be observed, palpated, or detected by diagnostic tests. The term is deliberately non-specific and refers to a change in structure or function rather than a particular disease. Lesions can affect any organ or tissue and may result from injury, inflammation, infection, ischemia, degenerative processes, or neoplasia.

Lesions are commonly categorized by location and by underlying process. By location, examples include skin lesions, brain lesions, and dental lesions. By process, they may be traumatic, inflammatory, infectious, vascular, or neoplastic. Morphology also helps description, with terms such as solid, fluid-filled, or ulcerated, and in dermatology terms like macule, plaque, vesicle, or ulcer. In radiology, a lesion may be described as radiolucent or radiopaque.

Diagnosis typically combines clinical examination with imaging studies (such as X-ray, MRI, or CT) and, when needed, histopathological examination of a biopsy. A lesion is a sign or marker of an underlying condition rather than a diagnosis in itself; many lesions are benign, while others may indicate cancer or pre-cancerous changes.

Management depends on the underlying cause and may range from observation and medical therapy to surgical or interventional procedures. Prognosis varies with etiology, size, location, and whether the lesion is benign or malignant. Understanding the nature and cause of a lesion is essential for appropriate treatment and follow-up.