# Keratinocyte cancer (and why 'non-melanoma skin cancer' is being retired)

Source: https://onco.cc/terms/keratinocyte-cancer/  
OnCo record `keratinocyte-cancer` (Term). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The two commonest cancers in the world, basal cell carcinoma and cutaneous squamous cell carcinoma, both arise from keratinocytes, the cells that make up most of the outer layer of skin. They used to be lumped together as non-melanoma skin cancer, a name defined by what they are not; dermatologists have agreed to call them keratinocyte cancers instead.

## Summary

Basal cell carcinoma and cutaneous squamous cell carcinoma are about 75 percent and 25 percent respectively of the group (Cancer Research UK). Both come from keratinocytes in the epidermis, both are overwhelmingly caused by ultraviolet light, both occur mostly on the head, neck, forearms and hands, and both are cured in the great majority of people by removing them. Melanoma comes from a different cell, the melanocyte, behaves differently and is on its own pages here.

The old name, non-melanoma skin cancer, has two faults. It defines a group by what it is not, and it quietly includes things that are not keratinocyte cancers at all: the ICD-10 code it is usually read as, C44, is a site code covering all malignant neoplasms of skin other than melanoma, so Merkel cell carcinoma and the adnexal carcinomas fall inside it too, and mortality figures published for 'non-melanoma skin cancer' may include them. A European consensus group of dermato-oncologists voted unanimously in 2024 for the consistent use of keratinocyte cancer instead, on the ground that it is more precise and correct by cause, and that this should help patients and doctors understand each other (Philipp-Dormston 2024). Their definition of the group includes the precursors, actinic keratosis and Bowen's disease, as keratinocyte-derived.

The practical consequence for anybody reading statistics is that the two names do not cover quite the same thing, and that C44 is a site code rather than a diagnosis: basal cell carcinoma and squamous cell carcinoma are told apart only by the morphology code the pathologist adds, not by the ICD-10 code. This matters more than it sounds, because it is one of the reasons the counting is as difficult as it is.

## Fields

- Kind: Term
- Last checked: 2026-09-25
- Also known as: keratinocyte cancer; keratinocyte carcinoma; KC; keratinocyte skin cancer; non-melanoma skin cancer; NMSC; non melanoma skin cancer; keratinocyte-derived skin cancer; C44; ICD-10 C44

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Skin_cancer
- Philipp-Dormston et al., Acta Dermato-Venereologica 2024;104:adv40601: a European consensus on the consistent use of the term 'keratinocyte cancer': https://doi.org/10.2340/actadv.v104.40601
- Cancer Research UK: types of non-melanoma skin cancer: https://www.cancerresearchuk.org/about-cancer/skin-cancer/types
- WHO ICD-10 (2019): C43 to C44 melanoma and other malignant neoplasms of skin; D04 carcinoma in situ of skin; L57.0 actinic keratosis, under skin changes due to chronic exposure to nonionizing radiation: https://icd.who.int/browse10/2019/en
- van Bodegraven et al., British Journal of Dermatology 2023;188(6):777 to 784: 'Get Data Out' Skin, national cancer registry incidence and survival rates for all registered skin tumour groups for 2013 to 2019 in England: https://doi.org/10.1093/bjd/ljad033
- Kwiatkowska et al., Skin Health and Disease 2021;1(4):e61: an updated report on the incidence and epidemiological trends of keratinocyte cancers in the United Kingdom 2013 to 2018: https://doi.org/10.1002/ski2.61

## Connected records

- terms: [Actinic keratosis (solar keratosis): sun damage, not cancer](https://onco.cc/terms/actinic-keratosis/), [Carcinoma](https://onco.cc/terms/carcinoma/), [Carcinoma in situ (CIS)](https://onco.cc/terms/carcinoma-in-situ/), [How skin carcinoma is staged in Britain: UICC TNM, and why it is not the American system](https://onco.cc/terms/tnm-skin-carcinoma/), [Inherited syndromes that cause skin cancer: Gorlin syndrome and xeroderma pigmentosum](https://onco.cc/terms/inherited-skin-cancer-syndromes/), [Keratoacanthoma: the tumour that may be a squamous cell carcinoma](https://onco.cc/terms/keratoacanthoma/), [Squamous cell carcinoma](https://onco.cc/terms/squamous-cell-carcinoma/), [The growth pattern on a basal cell carcinoma report: nodular, superficial, infiltrative, basosquamous](https://onco.cc/terms/bcc-growth-pattern/), [The subtype and grade on a cutaneous squamous cell carcinoma report](https://onco.cc/terms/cscc-subtype-and-grade/), [Why nobody knows how many skin cancers there are: the counting rule behind every figure](https://onco.cc/terms/keratinocyte-cancer-counting/)
- pathways: [Field cancerisation](https://onco.cc/pathways/field-cancerisation/)
- cancers: [Basal cell carcinoma](https://onco.cc/cancers/basal-cell-carcinoma/), [Bowen's disease (squamous cell carcinoma in situ)](https://onco.cc/cancers/bowens-disease/), [Cutaneous squamous cell carcinoma](https://onco.cc/cancers/cutaneous-scc/), [Merkel cell carcinoma](https://onco.cc/cancers/merkel-cell-carcinoma/), [Skin cancer (all types)](https://onco.cc/cancers/skin-cancer/)
- fronts: [Diagnostics & Biomarkers](https://onco.cc/fronts/diagnostics/)

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