Case Number : Case 2402 - 13 September 2019 Posted By: Dr. Richard Carr

Verrucous Carcinoma.

The nests in the dermis are too irregular to be verrucous carcinoma. Verrucous carcinoma usually has a pushing invasive borders. I do not see any in situ component, actually the superficial epithelium looks OK. I don't think I can call this SCC.

I called this an anal skin tag with pseudoepitheliomatous hyperplasia probably related to an allergic contact and / or irritant dermatitis. Striking eosinophilic spongiosis with myeloid dendritic cell clusters in the epidermis (used to be considered Langerhan's cells  but they are CD1a+, S100-, Langerin- as far as a recent paper on the eczemas). They have been called pseudopautrier's microabscesses but can also be seen in MF.

The patterns on p16 (checker-board pattern of cyto-nuclear staining) and p53 (peripheral wild type) are "reactive". EVG shows absolutely no entrapment (consistent with a non-invasive lesion in the setting of carcinoma but probably not relevant in this case).