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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.
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.
Each skin cancer comes from a different cell layer: melanocytes and basal cells at the base of the epidermis, keratinocytes above them, Merkel cells and blood vessels in the dermis; depth of invasion decides the risk.
Same organ: Melanoma, Basal cell carcinoma, Cutaneous squamous cell carcinoma, Merkel cell carcinoma, Kaposi sarcoma, BRAF V600-mutant melanoma, Stage III melanoma (after surgery), Stage IIB and IIC melanoma, Advanced melanoma (unresectable stage III and stage IV), Mucosal melanoma, Acral melanoma, Advanced cutaneous squamous cell carcinoma, Locally advanced and metastatic basal cell carcinoma, Bowen's disease (squamous cell carcinoma in situ), Dermatofibrosarcoma protuberans
Showing the organ this term concerns: Skin cancer (all types).
Shares The growth pattern on a basal cell carcinoma report: nodular, superficial, infiltrative, basosquamous, Inherited syndromes that cause skin cancer: Gorlin syndrome and xeroderma pigmentosum, The subtype and grade on a cutaneous squamous cell carcinoma report, How skin carcinoma is staged in Britain: UICC TNM, and why it is not the American system.
Shares The subtype and grade on a cutaneous squamous cell carcinoma report, How skin carcinoma is staged in Britain: UICC TNM, and why it is not the American system, Cutaneous squamous cell carcinoma, Skin cancer (all types).
Shares The subtype and grade on a cutaneous squamous cell carcinoma report, How skin carcinoma is staged in Britain: UICC TNM, and why it is not the American system, Bowen's disease (squamous cell carcinoma in situ), Cutaneous squamous cell carcinoma.
Shares Field cancerisation, Cutaneous squamous cell carcinoma, Basal cell carcinoma, Skin cancer (all types).
Shares Carcinoma, Keratoacanthoma: the tumour that may be a squamous cell carcinoma, The growth pattern on a basal cell carcinoma report: nodular, superficial, infiltrative, basosquamous, Squamous cell carcinoma.
Shares Actinic keratosis (solar keratosis): sun damage, not cancer, Bowen's disease (squamous cell carcinoma in situ), Field cancerisation.
Shares The growth pattern on a basal cell carcinoma report: nodular, superficial, infiltrative, basosquamous, Bowen's disease (squamous cell carcinoma in situ), Cutaneous squamous cell carcinoma, Basal cell carcinoma.
Shares Field cancerisation, Cutaneous squamous cell carcinoma, Basal cell carcinoma, Skin cancer (all types).