Basosquamous carcinoma

LAST UPDATED: Jan 20, 2026

Introduction

A basosquamous carcinoma (BSC) is a rare type of skin cancer with histological features of both basal cell carcinoma (BCC) and squamous cell carcinoma (SCC).

This chapter is set out as follows:

Aetiology
Clinical findings
Images
Management

Aetiology

Current evidence suggests that a BSC is derived from a BCC with genetic alterations that undergo squamous differentiation
BSC accounts for 2.1-4.8% of all non-melanoma skin cancers
Fitzpatrick type I–II and high levels of UV exposure are considered potent risk factors. The tumour usually develops in elderly individuals with a strong male preponderance

Clinical findings

Distribution
- UV-exposed areas of the head and neck are the most commonly affected sites (82–97%), especially the perinasal area and ears
Morphology
- The clinical appearance of BSC is notably ambiguous, with no discernible differences from a typical BCC. In fact, a persistent nodule that eventually transforms into an ulcer represents the most characteristic clinical presentation for BSC
Dermoscopic features
- Characterised by features of both BCC and SCC

Clinical Images

Please refer to notes on image rights at bottom of the page with regards to individual image ownership.

Management

According to many authors, BSC is characterised by a more aggressive biologic behaviour that is almost equal to that of SCC; any suspected or confirmed BSC should be referred on an urgent skin cancer pathway to Secondary Care
For most BSC the first-line treatment is surgical excision with margins wider than those for low-risk BCC

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