Breslow index

Histological measure (measure of tumour thickness) in malignant melanoma, named after the US-American pathologist Alexander Breslow. The tumour thickness according to Breslow is suitable for assessing the stages of a malignant melanoma and the prognosis derived from it. The absolute thickness of the tumor parenchyma from the uppermost layer of the stratum granulosum of the epidermis to the deepest still detectable tumor tissue is measured on the formalin-fixed histological preparation. The tumor thickness was previously measured on a hematoxylin-eosin (HE) stained preparation. Today, preparations in which the tumour parenchyma was visualised by means of suitable antibodies (e.g. Melan A) are preferred. The tumour thickness according to Breslow is given in millimetres. In contrast to the Clark level, the tumour thickness according to Breslow is determined independently of the invasion of different skin layers.