What type of skin cancer arises from the cells in the stratum spinosum?

Squamous cell carcinoma is a type of skin cancer that originates from keratinocytes, which are the primary cell type found in the stratum spinosum layer of the epidermis. This layer is involved in the structural integrity of the skin and plays a key role in the skin's barrier function. When keratinocytes in the stratum spinosum become malignant, they can proliferate uncontrollably, leading to squamous cell carcinoma.

This type of cancer can present as a firm, red nodule or a flat sore with a scaly crust, and while it may spread to other parts of the body if left untreated, it is generally regarded as less aggressive than malignant melanoma, which arises from melanocytes, the pigment-producing cells located primarily in the stratum basale. Other skin cancers such as basal cell carcinoma originate from the stratum basale, and keratoacanthoma is considered a variant of squamous cell carcinoma that typically has distinctive clinical features. Understanding these differences highlights why squamous cell carcinoma specifically arises from cells in the stratum spinosum.