The Upgrading Clinical Subtype Classification of Basal Cell Carcinoma is Useful to Correlate With Its Histologic...

The existing clinical subtype classification of basal cell carcinoma (BCC) does not adequately reflect tumor invasiveness or its relationship with histologic patterns.

To suggest the upgrading classification of clinical subtype of BCC and evaluate its correlation with histologic subtypes and tumor invasiveness.

This study enrolled 422 patients with 425 biopsy-proven BCC lesions. All of the patients were treated by Mohs micrographic surgery (MMS) at our hospital from January 2018 to October 2021. All BCCs were categorized according to upgrading clinical subtype classification we suggest: Basic subtypes (including nodular [N], papular [P], superficial-elevated [SE]/-flat [SF]/-depressed [SD] and infiltrative [I] subtype) and combined subtype. We conducted a retrospective study through medical record, clinical photographs, pathologic slide and MMS sheets.

The most common in basic subtypes was SE (23.1%), followed by N (22.1%) and I (12.0%) subtype. Nodulo-infiltrative (N-I) (8.7%) was the most common in combined subtype. In N, P, SE and SF subtype (non-aggressive group), the rate of tumor with pigmentation (63.1%) was high, non-aggressive pattern (91.4%) in histologic subtype was observed much more. In SD, I and combined subtype (aggressive group), pigmentation (24.0%) was relatively rare, aggressive and mixed pattern (74.4%) in histologic subtype was observed more. More wider surgical margin and more MMS stage number were required in aggressive group than non-aggressive group.

The upgrading classification of BCC clinical subtype can be not only described briefly and concretely for clinical appearance of BCCs but also highly correlated with histologic subtypes and tumor invasiveness.