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RCPath margin reporting datasets

RCPath skin cancer datasets · standardised histopathology reporting · structured pathology reporting

The Royal College of Pathologists (RCPath) publishes minimum datasets and appendices for histopathology reporting of skin cancers. These define which data items should appear in reports for melanoma, cSCC, BCC and MCC, supporting consistency, completeness and alignment with AJCC / UICC TNM, BWH and RCPath margin conventions. Surgeons reading a skin-cancer pathology report should know what to expect and what to query at MDT.

CurrentLast reviewed 18 May 2026

Overview

  • RCPath skin datasets are hosted on the cancer datasets and tissue pathways hub. The core skin datasets currently cited here are the February 2019 RCPath datasets: G125 melanoma, G124 cSCC, G123 BCC and G126 MCC; the hub also carries later TNM 9 / SNOMED appendices.
  • Datasets specify exact wording, units, definitions and ordering — facilitate audit and inter-pathologist consistency.
  • Embedded in laboratory information systems via SNOMED-CT coding; structured (form-based) entry recommended.
  • Use the current RCPath hub entry and any locally adopted network proforma; several legacy skin dataset pages are marked "currently on hold" while appendices are updated.

Melanoma dataset essentials

Minimum mandatory items include:

  • Specimen type: punch / shave / excisional / WLE / re-excision.
  • Tumour type: superficial spreading, nodular, lentigo maligna, acral lentiginous, desmoplastic, spitzoid, naevoid, etc.
  • Breslow thickness (mm to nearest 0.1).
  • Ulceration: present / absent.
  • Mitotic rate: per mm² in dermal component.
  • Clark level (optional in AJCC 8 era; retained for pT1).
  • Microsatellite metastases: present / absent.
  • Lymphovascular invasion: present / absent / suspected.
  • Perineural invasion: present / absent.
  • Tumour-infiltrating lymphocytes (TIL): brisk / non-brisk / absent.
  • Regression: extent.
  • Co-existent naevus: yes / no.
  • Margins: peripheral and deep in millimetres; involvement; closest margin location.
  • pT stage (AJCC 8).
  • BRAF V600 status (when tested).
  • RCPath dataset edition used.

cSCC dataset essentials

Minimum mandatory items include:

  • Specimen type.
  • Tumour size: maximum dimension in mm.
  • Histological type: keratinising, acantholytic, spindle-cell, desmoplastic, verrucous, lymphoepithelioma-like.
  • Differentiation: well / moderate / poor.
  • Maximum tumour thickness (mm).
  • Level of invasion: papillary dermis / reticular dermis / subcutis / bone.
  • Lymphovascular invasion.
  • Perineural invasion: nerve diameter (mm), named-nerve involvement, intra- vs extra-tumoural.
  • Tumour budding: emerging item.
  • Margins: peripheral / deep / closest in mm.
  • pT (AJCC 8) and BWH staging.
  • HPV status if relevant.
  • Comment field for adverse / risk features (BAD 2020 high-risk feature checklist).

BCC dataset essentials

Minimum mandatory items include:

  • Specimen type.
  • Tumour size.
  • Histological subtype: nodular, superficial, infiltrative, morphoeic / sclerosing, micronodular, basosquamous, fibroepithelioma of Pinkus, with combinations.
  • High-risk features: BAD 2021 — infiltrative / morphoeic / micronodular / basosquamous subtypes; perineural invasion; size >2 cm; recurrent.
  • Maximum tumour thickness.
  • Perineural invasion.
  • Margins: peripheral / deep / closest.
  • Comment on incomplete excision risk.

Margin convention

  • Reported in millimetres (or stated as involved if 0 mm or transected).
  • Peripheral margin (named direction with orientation suture) and deep margin reported separately.
  • Close margin: typically <1 mm cSCC; <0.5 mm BCC (centre-dependent).
  • For Mohs and en-face permanent sections: percentage of margin examined should be specified (100% with Mohs).
  • For re-excision: residual tumour status (none / in situ only / invasive).

Practical use for surgeons / MDT

  • If a dataset item is missing, request supplementary comment from pathologist before MDT.
  • Verify AJCC 8 / BWH stage from the dataset elements; do not rely on a stated pT alone.
  • Confirm the dataset and TNM appendix used — older reports may pre-date AJCC 8 changes (0.8 mm cut-point, T0), while new local templates may incorporate UICC TNM 9 appendices.
  • For research / audit: structured datasets enable batch extraction.
  • For training: trainees should be able to map dataset items to BWH and AJCC stage.

References

  1. Royal College of Pathologists. Dataset for histopathological reporting of primary cutaneous malignant melanoma and regional lymph nodes (G125). London: RCPath; February 2019.
  2. Royal College of Pathologists. Dataset for histopathological reporting of primary invasive cutaneous squamous cell carcinoma and regional lymph nodes (G124). London: RCPath; February 2019.
  3. Royal College of Pathologists. Dataset for histopathological reporting of primary cutaneous basal cell carcinoma (G123). London: RCPath; February 2019.
  4. Royal College of Pathologists. Dataset for histopathological reporting of primary cutaneous Merkel cell carcinoma and regional lymph nodes (G126). London: RCPath; February 2019.
  5. British Association of Dermatologists. UK guidelines for the management of basal cell carcinoma 2021. Br J Dermatol. 2021;185:899-920.
  6. Keohane SG et al. British Association of Dermatologists guidelines for the management of people with cutaneous squamous cell carcinoma 2020. Br J Dermatol. 2021;184(3):401-414.

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