subtypessquamous

Subtypes of squamous cell carcinoma (SCC) describe variations in differentiation and morphology of squamous neoplasms, as well as their anatomical location. This includes patterns seen in tumors arising from keratinized skin versus non-keratinized mucosal surfaces.

In normal tissue, stratified squamous epithelium is keratinized on the skin, forming a cornified epidermal layer, and non-keratinized on mucosal surfaces such as the oral cavity and esophagus, where cells retain nuclei to a greater extent.

Within SCC, common subtypes include keratinizing (well-differentiated) SCC, characterized by keratin pearls and abundant keratin; non-keratinizing SCC, with minimal keratinization and higher-grade appearance; basaloid SCC, composed of nests of basaloid cells and aggressive behavior; verrucous SCC, a well-differentiated, exophytic, slow-growing variant with local invasion but low metastatic potential; spindle cell (sarcomatoid) SCC, showing spindle-shaped cells and sarcoma-like features; adenosquamous carcinoma, containing both glandular and squamous components; papillary SCC, with papillary architectural projections.

These subtypes occur in multiple organs, including the skin, head and neck, esophagus, cervix, and lungs. Diagnosis relies on histology and immunohistochemistry; markers such as p40 and p63 support squamous differentiation, while cytokeratins help define subtype. HPV status is relevant for some mucosal sites.

Prognosis and treatment vary by subtype and stage; management commonly includes surgical resection with or without radiotherapy and chemotherapy. Some variants, like verrucous SCC, may have favorable local control but rare metastasis, whereas basaloid and spindle cell variants may be more aggressive.