Case Number : Case 1870 - 28 July - Dr Richard Carr Posted By: Guest

wondering if there is vasculitis, don't know if the dense pink stuff is fibrin. patient may be immunocompromised (given the history) so stains for bugs; ? reaction to drugs. doesn't look like lymphoma to me but then i have little expertise in this area.

My feeling was that the main pattern is that of an acute folliculitis with pustular formation and some lichenoid infiltrate. I would perform some serial sections, special stains for microorganisms, and of course check for herpes and other viruses. The lichenoid infiltrate puzzles me, that is why I think is wise to remark that a drug reaction cannot be discarded. There was this term used in the past: follicular toxic pustuloderma for some drug reactions but they are actually cases of AGEP, and as we know this is generalized and not localized like in this case.

What about an arthropod bite reaction in patient with Richter syndrome ( cll in DLBCL transformation )?

Looks folliculitis, may be viral? 

Definitely acute folliculitis. To rule out bugs. In addition there is almost an interface in images 3 & 5. Drug induced folliculitis?

Dear All 

Images 7- 11 added at the request of Dr Carr. 

DermpathPRO Admin

Happy Weekend!

Viral folliculitis

Intra-epidermal collection of mixed inflammatory cell + necrotic keratinocytes overlying a clear folliculitis. At DEJ, the individual lymphocytes seems to be surrounded by a clear halo "lymph in holes" they are aligned along DEJ, I couldn't see convincing apoptosis at this level. 

If colleagues agree that this is interface/lichenoid, would appreciate if they elaborate on why? 

Infective cause is crucial to exclude especially herpes folliculitis in the current context. Aware IHC for HSV/VZV is an option but from Clinician point of view, viral swab from the plaque for PCR is  a sensitive and extremely easy to do with results in 1-2 days. 

Herpes infection is one of the well known lymphoma mimicker which may fit well with some of the changes in this biopsy. 

Just for record, I have seen the first 6 photomicrographs only when posted the earlier comment and my screen was no refreshed whilst busy with typing so was not really aware of them! 

Yes, agree with HSV/VZV

nice case. 

Dr Richard Carr

Final Diagnosis: Herpes zoster folliculitis.

Thanks Admin for posting the diagnosis (I was on leave). I thought this was a nice example of prominent necrotic follicular keratinocytes with sparse multinucleate cytopathic changes in keeping with VZV folliculitis. In fact the clinical was of numerous pustules erupting on the chest and face on an erythematous base with a large vesicular plaque on the cheek ?varicella zoster. This case demonstrates the pseudolymphomatous pattern (presumably exaggerated here due to immune suppression) and interface reaction pattern that can be seen and if you miss the follicular involvement or subtle cytopathic changes (both absent in re-cut sections) you may not make the diagnosis. Well done to those for thinking of zoster on the first set of images.