Regression in

medicine Medicine is the science and Praxis (process), practice of caring for patients, managing the Medical diagnosis, diagnosis, prognosis, Preventive medicine, prevention, therapy, treatment, Palliative care, palliation of their injury or disease, ...

is the partial or complete reversal of a disease's

signs and symptoms Signs and symptoms are diagnostic indications of an illness, injury, or condition. Signs are objective and externally observable; symptoms are a person's reported subjective experiences. A sign for example may be a higher or lower temperature ...

. *Clinically, regression generally refers to a decrease in severity of

symptoms Signs and symptoms are diagnostic indications of an illness, injury, or condition. Signs are objective and externally observable; symptoms are a person's reported subjective experiences. A sign for example may be a higher or lower temperature ...

without completely disappearing. At a later point, symptoms may return. These symptoms are then called recidive. *In

cancer Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Po ...

, regression refers to a specific decrease in the size or extent of a

tumour A neoplasm () is a type of abnormal and excessive growth of tissue (biology), tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tiss ...

. In

histopathology Histopathology (compound of three Greek words: 'tissue', 'suffering', and '' -logia'' 'study of') is the microscopic examination of tissue in order to study the manifestations of disease. Specifically, in clinical medicine, histopatholog ...

, ''histological regression'' is one or more areas within a tumor in which neoplastic cells have disappeared or decreased in number. In

melanoma Melanoma is the most dangerous type of skin cancer; it develops from the melanin-producing cells known as melanocytes. It typically occurs in the skin, but may rarely occur in the mouth, intestines, or eye (uveal melanoma). In very rare case ...

s, this means complete or partial disappearance from areas of the

dermis The dermis or corium is a layer of skin between the epidermis (skin), epidermis (with which it makes up the cutis (anatomy), cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from s ...

(and occasionally from the

epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and Subcutaneous tissue, hypodermis. The epidermal layer provides a barrier to infection from environmental pathogens and regulates the ...

), which have been replaced by fibrosis, accompanied by melanophages, new blood vessels, and a variable degree of inflammation.

References

Epidemiology Medical terminology {{disease-stub