Case Number : Case 1593 - 03 August Posted By: Guest

I thought of large cell transformation in MF and I think that the fact that the same clone was demonstrated actually favours large cell transformation over LyP. Clnicopathologic correlation really important also....

Actually I read a bit more and same clone can be present in both entities, the most important is the clinical setting. If clinically is more suggestive of LyP it should be LyP but if patient is clinically in bad shape and worsening should be called transformed MF. By the way, correct me if im wrong but I think if the clinical is rather benign we could call it CD30+ lymphoproliferative disorder as it could also be primary cutaneous anaplastic large cell lymphoma (also indolent as LyP); the most specific feature for favouring LyP would be the classic recurrent self-healing papules.

Raul's second comment summarises this case very well!

Yes, the distinction is heavily dependent on the clinical presentation and course of lesions. Purely from a histological point of view, this is basically a CD30 rich T cell lymphproliferation which could be compatible with a transformed MF, primary cutaneous ALCL or LyP, type C... ( @Vincenzo, the infiltrate was quite deep in another section and the surface is ulcerated rather than showing epidermotropism, so would classify as type C rather than Type B LyP).

At our MDT, I was informed that 2 of the lesions have started showing spontaneous regression, the third is still persistent. Remember, Lyp may not always present with crops of lesions but may be oligolesional and the regression period may be over weeks to months. There was some concern amongst our haematologists that an identical clone implies transformed MF, but as you all have rightly commented LyP often shows the same clone as the associated MF. (thanks for the reference Vincenzo, I quoted the same one in my report and to the concerned haematologists!).