Case Number : Case 1654 - 27 October Posted By: Guest

An interesting case from Arti Bakshi, what do you think of this one?

Cheers, Geoff - DermpathPRO Projects

Bowen/SCC with sebaceous diff?

Reticulated acanthoma with sebaceous diff ( alias eccrine poroma with seb diff ).

On October 27, 2016 at 14:32, vincenzo polizzi said:

Reticulated acanthoma with sebaceous diff ( alias eccrine poroma with seb diff ).

 

Vincenzo, you have just preceded me by 9 minutes !!!!

I was just going to write reticulated acanthoma with sebaceous differentiation when I got an interrupting phone call !!!! I do not perceive any malignant features. 

Sorry for this setback, Mona, but you know...the best champions are sometimes and fortuitously preceded by someone...but they remain the best! And sincerely I really appreciate a lot your comments. Thanks very much :-)

At low power view, the broad anastomosing trabeculae connected to the epidermis make me think of poroma. Moreover, lesion comprises small basaloid cells and squamoid cells, and there are round spaces lined by an eosinophilic cuticle and small intracytoplasmic vacuoles reminiscent of ductal differentiation. So I favor poroma with sebaceous differentiation.

Nice and challenging case, Arti. And thanks to welcome me back.

Favor reticulated acanthoma with sebaceous differentiation over poroma with sebaceous differentiation. Nice case.

Reticulated acanthoma with sebaceous differentiation

Waiting for final answer...

This was diagnosed as a Poroma with sebaceous differentiation. Reticulated acanthoma with sebaceous differentiation is a perfectly reasonable d/d. Robeldo's arguments for favouring poroma are spot on! I agree that there is an admixture of poroid and squamoid cells with ductal differentiation, all of which favours poroma. Also the architecture is more poroma like with fairly deep downward extensions, whilst RASD would probably be more superficial and broad  in its silhouette.

The case actually belongs to my colleague Dr Mikhail (many thanks to her for sharing this case) and she had taken a second opinion from Dr Thomas Brenn, who also thought it was a poroma with sebaceous differentiation.

Nice Arti, what about superficial epithelioma with seb diff. According to McKee's, it shows ductal formations and it says that RESD falls in the spectrum of superficial epithelioma with seb differentiation?

@Mona, I think that these are related (if not the same) entities. Acc to Kazakov's textbook, RESD was a term introduced by Steffen and Ackerman to replace the previous designation of 'superficial epithelioma with seb diff'. The picture in Mckee does show clear ductal differentiation, (as can any lesion showing sebaceous differentiation). so I suppose that does not help to differentiate from poroma. 

Kazakov lists 3 features to distinguish RESD from poroma with seb differentiation: poroid cells, intracytoplasmic lumina and enlarged squamoid cells. But I agree that the distinction is not so clear cut in this case!