Nodular; centred in dermis; sheets-fascicles of spindle cells
Eosinophilic cytoplasm
Ovoid nuclei with occasional multinucleation and areas of marked pleomorphism; conspicuous mitotic activity
Marked solar elastosis; chronic inflammation
IHC: (-) keratins and p63
Many consider these tumours to represent dedifferentiated squamous cell carcinoma (PMID: 24705313)