Case Number : CT0049 Adam_Bates

Herpes folliculitis.
 

Agree with HSV, but i think this clinical aspect of the lesion is somewhat odd.
 

Yes looks like herpetic folliculitis, very weird clinical impression...
 

Undoubtedly, there are signs of herpes virus infection. But the peculiar clinical presentation makes me think of development of herpes virus infection in a previous inflammatory skin disease, like a spongiotic dermatitis or a burn, hence it would be eczema herpeticum or Kaposi's varicelliform eruption.

I would include chemotherapy effect, sun burn, porokeatsi., GVHD, and most preferably, actinic keratosis in my long differential.
 

Herpetic folliculitis with strange clinical feature
 

Herpes zoster. Affection of hair follicle is a clue for diagnosis of HZ by H&E as in this case that confirmed by histochemistry

I wonder if this is an incidental finding given its focality, at the edge of a broad, superficial shave. There is also an inflammatory infiltrate across the entire biopsy and a focus of calcification on the opposite side of the biopsy. Perhaps deeper levels into this block or a deeper biopsy would identify a cause for the clinical-pathological discrepancy.
 

Great! Thanks for the follow-up. Certainly an odd clinical presentation.!
 

gree with Noonshin that there might be more at work than isolated VZV, given the 2-year history of a translucent isolated forehead plaque, and clinical absence of classic zoster features. In first image, dermis does show some sclerosis and possible patchy depletion of basophilic elastotic fibers in the center, reminiscent of a superficially represented actinic granuloma (annular elastolytic giant-cell granuloma).

Given the unusual clinical context of long-term plaque, I'd wonder if this case represented one of the following scenarios:
1) incidental zoster developing in a previous isolated inflammatory dermatosis,
2) a inflammatory dermatosis that may be a direct result of previous zoster