Breslow thickness
Oncology, staging and radiology
Also known as: Breslow depth · Tumordicke nach Breslow · Breslow-Dicke · Breslow kalınlığı · Breslow tumour thickness (cutaneous melanoma) and AJCC 8th edition T category
What it is for
Breslow thickness is the vertical depth of an invasive cutaneous melanoma in millimetres, measured with a calibrated ocular micrometer from the top of the granular layer of the epidermis (or from the base of an ulcer) to the deepest invasive tumour cell. Microsatellites are not included. Under the 8th edition it is reported to the nearest 0.1 mm.
Classification
| Category | Description |
|---|---|
| Tis | melanoma in situ. |
| T1 | ≤1.0 mm. T1a: <0.8 mm without ulceration. T1b: <0.8 mm with ulceration, or 0.8–1.0 mm with or without ulceration. |
| T2 | >1.0–2.0 mm (T2a without, T2b with ulceration). |
| T3 | >2.0–4.0 mm (T3a without, T3b with ulceration). |
| T4 | >4.0 mm (T4a without, T4b with ulceration). |
| TX / T0 | TX thickness cannot be assessed (e.g. curettage); T0 no evidence of primary tumour (unknown or fully regressed primary). |
| Note | the mitotic rate is no longer a T1 criterion in the 8th edition (it was in the 7th); rounding means e.g. 0.75 mm is reported as 0.8 mm (T1b). |
Source
Thickness, cross-sectional areas and depth of invasion in the prognosis of cutaneous melanoma
Ann Surg 1970;172:902–908 (Breslow A)
DOI: 10.1097/00000658-197011000-00017
PMID: 5477666
- Edition
- Breslow 1970; T categories per AJCC Cancer Staging Manual 8th edition (2017)
- Checked on
Summary of the published classification in our own words. Not a substitute for the original publication.
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