Breslow thickness

How deep a melanoma has grown into the skin, in millimetres. The single strongest predictor of whether it will spread.

Measured from the granular layer to the deepest tumour cell. Drives T stage (T1 ≤1 mm to T4 >4 mm), sentinel node biopsy decisions (generally offered from ~0.8 mm or with ulceration), and adjuvant eligibility. Ulceration upstages within each thickness band.

Pathology: what this kind of term is about · animated schematic, not to scale