# The subtype and grade on a cutaneous squamous cell carcinoma report

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## TL;DR

A squamous cell carcinoma report carries two separate things: a subtype, which is the shape the tumour grows in, and a grade, which is how much it still looks like normal skin. Most are of no special type and well differentiated. Four subtypes and the poorly differentiated grade are counted as high risk in Britain.

## Summary

**The subtype.** The UK dataset uses a modified WHO classification and recognises that a squamous cell carcinoma may come from surface epidermis or from hair follicle epithelium, either of which can be in situ or invasive and low or high risk (RCPath G124). If none of the named subtype features are present, the tumour is reported as **no special type**, also called classic, and that is what most are. The subtypes national guidelines and NICE treat as clinically high risk are **acantholytic** (cells falling apart from one another, leaving pseudoglandular spaces), **desmoplastic** (defined as having more than 30 percent desmoplastic stroma) and **spindle cell** or sarcomatoid. The dataset notes a real disagreement about spindle cell tumours: the Armed Forces Institute of Pathology accepts spindle cell carcinoma arising after radiotherapy as high risk but regards spindle cell tumours on sun-exposed skin as not carrying the same aggressive potential. **Adenosquamous** carcinoma is high risk to WHO. Invasive squamous cell carcinoma with adjacent Bowen's disease is usually treated as high risk, although there is increasing debate about whether that should be restricted to areas not exposed to ultraviolet light. **Basaloid** squamous cell carcinoma is uncommon in skin, must be told from basal cell carcinoma with immunohistochemistry (BerEP4 and EMA), may arise in pre-existing basaloid Bowen's disease, and is poorly differentiated by definition.

**The grade.** Both UICC and AJCC equate grades 1 to 4 with well, moderately, poorly and undifferentiated, and accept that 3 and 4 can be combined. The UK dataset considered the original Broders method, which scores the percentage of well-differentiated tumour present, and after consultation adopted a three-grade system instead. Well differentiated tumours show easily recognisable and often abundant keratinisation, obvious squamous cells with visible intercellular bridges, minimal pleomorphism and mostly basal mitoses. Moderately differentiated tumours are more disorganised, with more nuclear and cytoplasmic pleomorphism, more and abnormal mitoses, and keratin limited to keratin pearls, horn cysts and scattered single keratinised cells. In poorly differentiated tumours it may be hard to establish the nature of the lesion at all unless intercellular bridges or small foci of keratinisation are found; rarely the tumour is completely anaplastic and keratin immunohistochemistry is needed.

The grading rule matters and is not obvious. AJCC gives no guidance on what percentage of a differentiated component sets the grade, so the UK dataset follows the widely used approach of classifying a tumour by **its most poorly differentiated region, irrespective of the percentage present**. A tumour that is 95 percent well differentiated with one poorly differentiated focus is a poorly differentiated tumour on a British report. Recording the percentages of each component is optional. Loss of differentiation correlates with clinical risk, which is the whole reason the grade is there.

## Fields

- Kind: Term
- Last checked: 2026-09-25
- Also known as: acantholytic squamous cell carcinoma; desmoplastic squamous cell carcinoma; spindle cell squamous cell carcinoma; sarcomatoid squamous cell carcinoma; adenosquamous carcinoma of skin; basaloid squamous cell carcinoma; well differentiated squamous cell carcinoma; moderately differentiated squamous cell carcinoma; poorly differentiated squamous cell carcinoma; cSCC grade; cSCC subtype; Broders grade; no special type squamous cell carcinoma; classic squamous cell carcinoma

## Notes

- Two of the UK's high-risk subtypes are not WHO subtypes at all. The fourth edition of the WHO skin classification (2018) listed squamous cell carcinoma with acantholytic, spindle cell, verrucous, adenosquamous and clear cell subtypes, plus a group of other uncommon variants. The fifth edition (2025) lists verrucous, acantholytic, lymphoepithelial, clear cell, spindle cell and squamous cell carcinoma with sarcomatoid differentiation, and made four deliberate changes: adenosquamous carcinoma is no longer a subtype of cutaneous squamous cell carcinoma, because evidence of ductal differentiation supports classifying most of these tumours as squamoid eccrine ductal carcinoma; pseudovascular squamous cell carcinoma is no longer a subtype and is not recommended as a term for acantholytic carcinoma; sarcomatoid differentiation is now the only acknowledged uncommon subtype; and lymphoepithelioma-like is not recommended for lymphoepithelial carcinoma. Desmoplastic squamous cell carcinoma, which the UK singles out as high risk and defines by more than 30 percent desmoplastic stroma, has never had a WHO heading in either edition: it is an AJCC, BAD, NICE and SIGN construct. So is the UK's treatment of adenosquamous carcinoma as a high-risk subtype of this cancer, which the fifth edition has now moved elsewhere. Where a British report and an international reference disagree about what the tumour is called, this is usually why.
- Why the report may say 'no special type'. It is not a shrug. The dataset defines it as the default for a surface-epidermal squamous cell carcinoma with none of the high-risk subtype features present, and diagnostic uncertainty about the subtype is entered separately as 'uncertain'. Reading 'no special type' on a report is reading that the pathologist looked for acantholytic, desmoplastic, spindle cell and adenosquamous features and did not find them.
- A grade is not a stage and neither is a risk band. The grade says how abnormal the cells look; the stage says how big the tumour is and where it has reached; the risk band is what a clinician or a multidisciplinary team makes of both together plus the site, the immune state and the margins. A well-differentiated 5 cm tumour and a poorly differentiated 5 mm one are the same grade question answered differently and the same stage question answered differently again.

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Squamous-cell_carcinoma_of_the_skin
- Royal College of Pathologists G124: dataset for histopathological reporting of primary invasive cutaneous squamous cell carcinoma and regional lymph nodes, version 4, February 2019 (Slater and Barrett): https://www.rcpath.org/resourceLibrary/g124datasetsquamous-pdf.html
- Cancer Research UK: squamous cell carcinoma of the skin: https://www.cancerresearchuk.org/about-cancer/skin-cancer/types/squamous-cell-carcinoma
- Keohane et al., British Journal of Dermatology 2021;184(3):401 to 414: British Association of Dermatologists guidelines for the management of people with cutaneous squamous cell carcinoma 2020: https://doi.org/10.1111/bjd.19621
- WHO Classification of Tumours Editorial Board: Skin tumours, 5th edition, volume 12 (IARC, Lyon, 2025), ISBN 978-92-832-4535-3: https://publications.iarc.who.int/Book-And-Report-Series/Who-Classification-Of-Tumours/Skin-Tumours-2025
- Elder, Massi, Scolyer and Willemze (eds): WHO Classification of Skin Tumours, 4th edition, volume 11 (IARC, Lyon, 2018): https://publications.iarc.who.int/Book-And-Report-Series/Who-Classification-Of-Tumours/WHO-Classification-Of-Skin-Tumours-2018
- Histopathology 2026;88:555 to 568: WHO classification of skin tumours, key updates in the fifth edition (open-access summary of what the 2025 volume changed): https://doi.org/10.1111/his.15562
- IARC and the International Association of Cancer Registries: ICD-O-3.2 morphology and behaviour codes (actinic keratosis 8070/0; Bowen disease 8081/2; keratoacanthoma a related term under 8071/3; micronodular basal cell carcinoma shares 8097/3 with nodular, and sclerosing or morphoeic shares 8092/3 with infiltrating): http://www.iacr.com.fr/index.php?option=com_content&view=category&layout=blog&id=100&Itemid=577

## Connected records

- terms: [Actinic keratosis (solar keratosis): sun damage, not cancer](https://onco.cc/terms/actinic-keratosis/), [Grade](https://onco.cc/terms/tumour-grade/), [Histology](https://onco.cc/terms/histology/), [How skin carcinoma is staged in Britain: UICC TNM, and why it is not the American system](https://onco.cc/terms/tnm-skin-carcinoma/), [Keratinocyte cancer (and why 'non-melanoma skin cancer' is being retired)](https://onco.cc/terms/keratinocyte-cancer/), [Keratoacanthoma: the tumour that may be a squamous cell carcinoma](https://onco.cc/terms/keratoacanthoma/), [Perineural invasion (PNI)](https://onco.cc/terms/perineural-invasion/), [Squamous cell carcinoma](https://onco.cc/terms/squamous-cell-carcinoma/), [The Brigham and Women's Hospital staging system, and why squamous cell carcinoma has two](https://onco.cc/terms/bwh-staging-cscc/), [The growth pattern on a basal cell carcinoma report: nodular, superficial, infiltrative, basosquamous](https://onco.cc/terms/bcc-growth-pattern/), [Tumour differentiation (well / moderately / poorly differentiated)](https://onco.cc/terms/tumour-differentiation/), [What makes a skin cancer high risk: the UK feature lists](https://onco.cc/terms/skin-cancer-high-risk-features/)
- cancers: [Advanced cutaneous squamous cell carcinoma](https://onco.cc/cancers/advanced-cutaneous-scc/), [Bowen's disease (squamous cell carcinoma in situ)](https://onco.cc/cancers/bowens-disease/), [Cutaneous squamous cell carcinoma](https://onco.cc/cancers/cutaneous-scc/), [Skin cancer (all types)](https://onco.cc/cancers/skin-cancer/)
- fronts: [Diagnostics & Biomarkers](https://onco.cc/fronts/diagnostics/)

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