Case Number : CT0076 Adam_Bates

I think we r having a follicle (and apocrine duct) related interface changes, spongiosis, exocytosis, secondary acantholysis, dyskeratotic cells, vesiculation and related dermal inflammatory cell infiltrate with overlying hyperkeratosis and parakeratosis. This together with the clinical presentation, I am thinking of fox fordyce disease (apocrine miliaria), but the strange thing is that fox fordyce is usually pruritic?

In my oppinion the most striking feature is the presence of numerous Langerhans cells. Although the first idea is Langerhans cell histiocytosis, the first images suggest lichen planus. There are foci of epidermal hyperplasia, hyperkeratosis and hypergranulosis associated with band-like lymphohistiocytic infiltrates and vacuolar alteration of dermo-epidermal junction. I think this could be lichen planus pigmentosus inversus with associated Langerhans cell hyperplasia.
 

Folliculocenteric Langerhans cell histiocytosis mimicking lichen planus.
 

This was a case from far afield but I noted that the patient was taking citalopram.
 

Miliarial spongiosis and acantholysis. ?Acrosyringeal Grover's disease vs. drug reaction
 

Citalopram is a SSRI anti- depressant. These drugs are effective in controlling severe and chronic pruritus. Looking at the images again, I still think this is apocrine miliaria and may be the lesions are asymptomatic because of the citalopram... May be..
 

I was struck by the acrosyringeal centric location of this flexural lichen planus-like reaction and raised the posibility of a a drug (citalopram) induced lichen planus. The marked individual cell necrosis in addition to numerous Langerhan's cells and spongiosis to me together with the odd clinical features are good for a drug reaction. I was able to ascertain some evidence of reports of Citalopram induced lichen planus. Whether the drug is somehow being concentrated by the sweat ducts at the acrosyringium is obviously speculative but an interesting idea. I do not think this is Langerhan's cell histiocytosis because of the mixed infiltrate and clear cut lichenoid reaction pattern.