Case Number : Case 2741 - 7 January 2021 Posted By: Saleem Taibjee

I see a focal area of modest, psoriasiform epidermal hyperplasia with overlying parakeratosis.  The affected epidermis shows mild dysplasia and an increase in mitotic activity, which together make me think this is a solar keratosis.  I would do a PAS stain, expecting it to be negative.

In addition there is a modest perivascular lymphocytic infiltrate (some might call it lymphocytic "vasculitis") which may be a reflection of the underlying Behcet's disease.  The dermal collagen looks rather fragmented which might be due to systemic steroid treatment.

Maybe I´m out of track but I´m thinking in Grover disease.

Focal Psoriasiform epidermal changes with dermal perivascular lymphocytes

Get a PAS done to rule out fungus

I am not able to think beyond this, there is no granuloma or tumor in the dermis

On 08/01/2021 at 08:48, Alex-Ventura-Leon said:

Maybe I´m out of track but I´m thinking in Grover disease.

Yes, I am also suspicious of Grover's ds.

3 more levels and a pasx3 strip please

Not sure, but favor Grover’s disease. 

For a diagnosis of Grover's wouldn't you expect to see some acantholysis?

Not sure, Richard, but I seem to see a subtle acantholysis in fig 4...

Grover disease can have patterns with minimal acantholysis. Here a relevant paper: https://pubmed.ncbi.nlm.nih.gov/20526170/

I had the same impression as Vincenzo and interpreted figure 4 as subtle acantholysis.

However, i´m speculating and i´m looking forward for the final answer

Yes this is Grover’s disease. I did request levels, which did not significantly differ on this biopsy i.e. the rather subtle acantholysis did not become more prominent. However, in fact the patient had 2 biopsies. The histology from the second biopsy is shown below. As you can see it clearly showed acantholytic dyskeratosis.

The important lesson here is that elongation of rete ridges (solar lentigo-like) is a useful clue to ‘early’ Grover’s, and is highlighted in at least 2 publications – see below, as well as receiving a mention in Weedon’s textbook.

BW

Saleem

Thank you everyone.  I thought acantholysis was a sine qua non for Grover's disease.  With the eye of faith looking through a retrospectoscope I can see the very subtle changes of acantholysis in image 4.  Certainly acantholysis is much more obvious in the second biopsy Saleem.