Breslow Thickness
Pronunciation: BRES-low
The measurement of tumor depth from the granular layer to the deepest point of invasion, used for melanoma staging.
Full Definition
Breslow thickness is the most important prognostic factor in melanoma staging, representing the vertical measurement of tumor depth from the granular layer of the epidermis (or base of ulceration if present) to the deepest point of tumor invasion. Measured in millimeters using an ocular micrometer, this measurement guides treatment decisions including surgical margins and the need for sentinel lymph node biopsy. The current staging system categorizes melanomas as T1 (≤1.0mm), T2 (1.01-2.0mm), T3 (2.01-4.0mm), or T4 (>4.0mm), with further substaging based on ulceration and mitotic rate.
Usage
Usage note: Always express in millimeters to two decimal places; capitalize 'Breslow' as it is an eponym.
In Context
- "The melanoma showed a Breslow thickness of 2.3mm with ulceration present." — Pathology report
- "Surgical margins of 2cm were planned based on the Breslow thickness of 3.1mm." — Surgical planning note