Case Number : Case 1739 - 26 January - Dr Arti Bakshi Posted By: Guest

Dr Arti Bakshi has a great case to tickle your brain cells.

Geoff Cross - DermpathPRO Projects

I would perform some more t cell markers to see if there is loss of expression and check for tcr rearrangement. But I thought of primary cutaneous cd4 positive small/medium cell lymphoma although they will change the name of this entity soon

T-cell rich B-cell Follicular Cell Lymphoma. K/Lambda to confirm.

I don't know if this is primary cutaneous. BCL2?

Agree with Raul, I think this is best suited as the short-lived Primary cutaneous CD4+ small/medium pleomorphic T-cell lymphoma.

I will call it also small/medium pleomorphic T cell lymphoma with this phenotype presented (it can show lots of reactive B cells), but only after performing TCR gene rearrangement and proving thst these T cells are monoclonal. 

I prefer SMPTCL with the L meaning "lymphoproliferation". I don't believe it's a lymphoma although I guess it's a grey zone lesion (literally and figuratively). If solitary probably harmless. If clinically multiple and progressive would probably be treated as a low-grade cutaneous lymphoma i.e. local radiotherapy I guess.

Well done all....this is small/medium pleomorphic T cell lymphoma or  'lymphoproliferation' as Richard would prefer it! Agree with all the comments made above regarding this entity. It was included as a provisional entity in the last EORTC and awaits final categorisation.

Further immunos showed PD1 positivity in the T cells, CD30 was negative and TCRPCR showed monoclonality. I put this case in, particularly to highlight that these cases can have quite a proportion of B cells, leading to confusion with B cell lymphomas. @Vincenzo, if its any consolation, our haematopathologist (with whom we share our cutaneous lymphoma cases) was also worried about a B cell lymphoma initially but came around to SMPTCL once the full immunopanel and history was at hand. The lesion was excised and no other lesions have since developed.

Great case, Arti, thanks. I was thinking of a B cell neoplasm because of many large CD20+ cells, but yes, this is a SMPTCL, I'm convinced now...

And I've better learned this entity.