Looks like there is squamous cell carcinoma in situ. Infiltrative nests of malignant basaloid or squamous cell are seen in the dermis. The last two figures appear to show duct differentiation in the nests of tumor cells. 

Squamoid eccrine ductal carcinoma vs. basal cell carcinoma with ductal differentation. Favor the former.

Eccrine Porocarcinoma

Agree with above. Porocarcinoma!

Agree with porocarcinoma. The clue that it is arising from the acrosyringium is in fig 4.

Happy new year my friends!!!

Squamous cell carcinoma.

I'm awaiting some IHC to be posted.

I vote for porocarcinoma too.

Porocarcinoma.

I called it a high grade cutaneous carcinoma, basaloid (looks a little "bowenoid" i.e. undifferentiated to me) with focal ductal differentiation. I don't argue with calling it a porocarcinoma (high grade) or adenosquamous carcinoma (high grade).  Not sure if the focus of Bowen's at the edge is separate incidental as it was p16 rather diffuse c/w less staining in the rest of the tumour. I will ask again for the IHC to be posted (I did try!).

Looks like the IHC is now posted. On p63 we seen the central ductal differentiation losses the staining and is focally positive for Cam5.2 (low molecular keratins that are NOT normally seen in cutaneous SCC. I managed to loose the BerEP4 slide which also showed focal ductal luminal staining). Bowen's or bowenoid actinic keratosis is almost invariably diffusely nuclear p16 positive not the case in the invasive tumour here although both lesions are "positive" for p53.