Case Number : Case 1746 - 6 February - Dr Richard A Carr Posted By: Guest

Get your week off to a great start with this lovely case from Dr Richard A Carr

Geoff Cross - DermpathPRO Projects

crateriform lesion, thickened epidermis with upper layers showing HPV-like features, haemorrage in stratum corneum, no inflammation, no obvious elastic fibres in the epidermis and I couldn't see any convincing epidermodysplasia. considered regressed KA but to me this looks like an HPV induced lesion ?odd verruca.

Agree verruca

Verruca vulgaris

only differential i can think of is trichilemmal horn although for me this case is better classified as a verruca as you guys mentioned

Eosinophilic nuclear inclusions of keratinocytes of stratum corneum and infolding of elongated rete ridges towards a virtual central point of the base are in keeping with an old Viral Wart, I think. Not atypia nor glassy cytoplasmic changes as clues to KA, nor dermal scarring

Verruca.

Agree. Thought about an EV acanthoma, but the cytoplasm lacks the slate grey colour.

Looks like Verruca.

This lesion reminded me of a subset of the epidermal proliferative lesions we see in the patients on BRAF inhibitors for metastatic melanoma. I think as you all agreed it's just a viral wart and I also think it probably is HPV associated. However I do find the term "benign verrucous keratosis" quite an appealing appellation for such lesions especially when one cannot always force it easily into a viral wart. I think there is clearly a subset of sporadic verrucous keratoses (akin to the lesions seen in BRAFi receiving patients) that are probably HPV associated but that don't always have clearly diagnostic cytological features for HPV with certainty.  It seems the BRAFi associated lesions are often associated with the Beta type HPVs so perhaps Urmilla and Nitin are on to something.  Obviously this lesion grew rapidly so it is clinically mimicking the pattern seen in BRAFi induced lesions. I wonder if it might also have a mutation in a RAS or epidermal growth receptor gene etc.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4452444/