Breslow Thickness
A histological measurement, in millimetres, of the vertical depth of a melanoma from the granular layer of the epidermis to the deepest tumour cell.
Full Definition
Breslow thickness is the primary prognostic parameter for primary cutaneous melanoma, measured by a pathologist using an ocular micrometer on a stained tissue section. It is named after pathologist Alexander Breslow, who described the method in 1970. In editorial contexts, values must be expressed in millimetres to two decimal places (e.g., 1.50 mm) and should not be converted to centimetres. Breslow thickness directly informs the T-staging category under the AJCC Cancer Staging Manual and must be accurately transcribed from pathology reports into clinical summaries.
Usage
Usage note: Always capitalise 'Breslow' as it is an eponym. Express values in millimetres; do not use centimetres. Distinguish from Clark level, which is a now-deprecated depth classification system.
In Context
- "A Breslow thickness of 0.75 mm was recorded, placing the tumour in the T1a category." — Oncology MDT report
- "Proof-check that Breslow thickness values are in millimetres and carry two decimal places throughout the manuscript." — Copy-editing checklist