What is Breslow’s depth?

This is a more precise way of measuring the level of invasion of primary malignant melanoma. An ocular micrometer is used to directly measure the distance that tumor cells have invaded. The distance of invasion is measured from the top of the granular layer of the epidermis, or in ulcerated lesions, the base of the ulcer to the point of deepest invasion by the tumor cells. This measurement appears to be more easily reproducible among institutions and more objective than Clark’s levels. The Breslow tumor thickness is the strongest predictor of survival.

Payette MJ, Katz M 3rd, Grant-Kels JM: Melanoma prognostic factors found in the dermatopathology report, Clin Dermatol 27:53–74, 2009.