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Skin-Melanocytic Tumors

Clark’s levels of invasion

 

Last major update: November 2008 - next update November 2009

Revised: 22 September 2009

Author: Nat Pernick, M.D., PathologyOutlines.com, Inc.

Copyright: (c) 2002-2009, PathologyOutlines.com, Inc.

 

Uses

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● Used to define subcategories of T1 melanomas (1 mm or less in thickness) (J Natl Cancer Inst 1989;81:1893)

● NOT useful for melanoma of palm or sole

● Clark’s levels are related to incidence of nodal metastases but only consider primary tumor, not nodes or metastases

● Less prognostic significance than T classification (J Craniofac Surg 2007;18:1353)

Less reproducible than Breslow’s system (J Pathol 1991;163:245); also not always uniform due to variation in depth of skin layers

● 5 year disease free survival is 100% with level II, 88% with level III, 66% with level IV, 15% with level V

● Must recognize that deep collection of malignant melanocytes may be attached to a pilosebaceous unit

 

Definition

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I: not penetrating basement membrane (in situ)

II: in papillary dermis (difficult to differentiate II versus III (SEER)

III: filling and expanding the papillary dermis and stopping at the interphase between the papillary and reticular dermis

IV: in the reticular dermis

V: in the subcutaneous tissue

 

Diagrams

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image                             

Diagram of skin layers                      Clark’s levels

 

End of Skin-Melanocytic Tumors > Clark’s levels of invasion

 

 

 

This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must also be interpreted in the context of a patient's clinical data using reasonable medical judgment.  This website should not be used as a substitute for the advice of a licensed physician.

 

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