Clark's level is a
staging system, which describes the level of anatomical invasion of the
melanoma in the skin. It was developed by
Wallace H. Clark Jr.
Wallace H. Clark Jr. (May 16, 1924 – November 28, 1997) was an American dermatologist and pathologist. He is best known for devising the " Clark's level", or Clark Level, system for classifying the seriousness of a malignant melanoma skin c ...
at
Harvard University
Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of high ...
and
Massachusetts General Hospital
Massachusetts General Hospital (Mass General or MGH) is the original and largest teaching hospital of Harvard Medical School located in the West End neighborhood of Boston, Massachusetts. It is the third oldest general hospital in the United State ...
in the 1960s.
Levels
Five anatomical levels are recognized, and higher levels have worsening prognostic implications. These levels are:
*Level 1: Melanoma confined to 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 epidermis layer provides a barrier to infection from environmental pathogens and regulates the ...
(melanoma in situ)
*Level 2: Invasion into the
papillary dermis
The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided in ...
*Level 3: Invasion to the junction of the
papillary and
reticular dermis
The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided in ...
*Level 4: Invasion into the
reticular dermis
The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided in ...
*Level 5: Invasion into subcutaneous tissue.
National usage
In the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...
, the current staging system adopted by the
American Joint Committee on Cancer {{Short description, Organization standardising cancer staging
The American Joint Committee on Cancer (AJCC) is an organization best known for defining and popularizing cancer staging standards, officially the AJCC staging system.
The American Joi ...
(AJCC) no longer considers Clark's level, because it is less prognostic and more subjective than other alternatives.
However, it is a mandatory component for melanoma pathology in
Sweden.
See also
*
Staging of melanomas
*
Breslow's depth
In medicine, Breslow's depth was used as a prognostic factor in melanoma of the skin. It is a description of how deeply tumor cells have invaded. Currently, the standard Breslow's depth has been replaced by the AJCC depth, in the AJCC staging sy ...
References
{{reflist
External links
Melanoma Staging Systems National Cancer Institute. A resource on Clark's levels and Breslow's depth.
Original article from Breslow Cancer res, 1969.
Histopathology
Melanocytic nevi and neoplasms
Dermatologic terminology
Cancer staging