Case Number : Case 2656 - 10 September 2020 Posted By: Saleem Taibjee

The low power appearance suggests an ulcerated basal cell carcinoma.  However, palisading is not well seen and there is no retraction artefact.  Some cells show bubbly cytoplasm.  I suspect this is a BCC mimic such as sebaceous carcinoma or basaloid SCC.  IH should help.

The other thing is there is a pronounced lymphocytic infiltrate as far down as the fat.  Perhaps there are two pathologies going on here such as CLL?

3 hours ago, Richard Logan said:

The low power appearance suggests an ulcerated basal cell carcinoma.  However, palisading is not well seen and there is no retraction artefact.  Some cells show bubbly cytoplasm.  I suspect this is a BCC mimic such as sebaceous carcinoma or basaloid SCC.  IH should help.

The other thing is there is a pronounced lymphocytic infiltrate as far down as the fat.  Perhaps there are two pathologies going on here such as CLL?

Agree!

There are some palisades, but not in infiltrating solid aggregates. Instead I see a lobular, in situ, intra-sebaceous growth in superficial dermis, as well as it does the ocular sebaceous carcinoma. But this isn’t an ocular-periocular case( isn’t it?). Difficult, but favor a poorly differentiated sebaceous carcinoma. And agree with the CLL guesswork, also. 

BCC vs Basaloid SCC. I favor the first but IHC would be usefull (EMA, BerEP4)

it's a little bit weird, however it looks with neuroendocrine differentiation to me.

I would also keep the differential of sebaceous carcinoma, BCC and basaloid SCC.

I would also keep the differential of sebaceous carcinoma,  basaloid SCC but thinking of CLL from the lymphocytes i dont know, i will get a CBC done

some limited immunos below:

So it's BCC with neuroendocrine differentiation.  Is the degree of lymphocytic infitration significant, or just reactive to the tumour?

Yes, well done, this is a BCC with neuroendocrine differentiation. These can be spotted at low power as basaloid tumours that show a BCC architecture, but with cells showing these larger 'high grade' nuclei. I suspect they are not uncommon, but get readily missed during busy routine sign-out.

As far as I'm aware, there are no reported cases of metastasis (?), and hence this may be a rather academic observation, but probably still worthwhile mentioning within the histology report but clearly indicating the distinction from Merkel cell carcinoma, etc.

After the comments above, I did go back and double-check the accompanying infiltrate on the glass slide. This comprises mostly mature plasma cells with normal morphology, with admixed lymophocytes. Hence I believe it is reactive. The patient has a normal ful blood count.

Nice and educative case. Thanks Dr Saleem. 

Thanks a lot Dr for this interesting case

On 15/09/2020 at 14:56, Saleem Taibjee said:

Yes, well done, this is a BCC with neuroendocrine differentiation. These can be spotted at low power as basaloid tumours that show a BCC architecture, but with cells showing these larger 'high grade' nuclei. I suspect they are not uncommon, but get readily missed during busy routine sign-out.

As far as I'm aware, there are no reported cases of metastasis (?), and hence this may be a rather academic observation, but probably still worthwhile mentioning within the histology report but clearly indicating the distinction from Merkel cell carcinoma, etc.

After the comments above, I did go back and double-check the accompanying infiltrate on the glass slide. This comprises mostly mature plasma cells with normal morphology, with admixed lymophocytes. Hence I believe it is reactive. The patient has a normal ful blood count.

What made you do chromogrannin?