Case Number : Case 1816 - 15 May - Dr Limin Yu Posted By: Guest

Start your week off with a lovely case from Dr Limin Yu.

Geoff Cross - DermpathPRO Projects

A PPD-like rash, with eosinophils and chronic-like dermal fibrosis, but with acute-like epidermal features ( no parakeratosis/hyperkeratosis ) makes me think of fixed drug eruption. 

I also thought of drug adverse effect Vincenzo

Would like to R/O MF first and check drug history.. could be T cell pseudolymphoma (Lymphomatoid drug reaction) or MF

A superficial perivascular and interstitial inflammation of lymphocytes and plasma cells, with rare eosinophils, associated to wiry bundles of collagen and some extravasated erythrocytes in the papillary dermis. There's also lymphocyte tagging along dermoepidermal junction in the absence of spongiosis, disturbance of the stratum corneum, or another epidermal reaction pattern. I favor some sort of drug eruption, perhaps the fixed type, although prominent vacuolar change with apoptotic keratinocytes, deeper extension of the infiltrate, and neutrophils scattered interstitially are lacking.

Could this be an early changes of extragenital lichen sclerosus mimicking a CTCL histologically. There is epidermal atrophy with changes of the collagen bundles at the most superficial part of papillary dermis. Clinically such plaques are highly distinctive and a simple genital examination can be rewarding rather than attempting to diagnose CTCL on the histology alone. While lesions of MF can occur at any part of the skin, isolated arm involvement will be slightly unusual as well clinically (if this is the sole site of the lesion).

My first thought was inflammatory stage of Lichen sclerosus. Kept quiet as no one else mentioned it! 

11 hours ago, Saman Fatah said:

Could this be an early changes of extragenital lichen sclerosus mimicking a CTCL histologically. There is epidermal atrophy with changes of the collagen bundles at the most superficial part of papillary dermis. Clinically such plaques are highly distinctive and a simple genital examination can be rewarding rather than attempting to diagnose CTCL on the histology alone. While lesions of MF can occur at any part of the skin, isolated arm involvement will be slightly unusual as well clinically (if this is the sole site of the lesion).

Very good suggestion of inflammatory LS !!

LS was my "spot diagnosis" but curious amount of haemosiderin! There are reports of vascuolopathic changes in genital LS.

Answer??

My differentials are LS and a drug reaction. I have had a case where LS had unusual amounts of hemosiderin.

I hope you enjoyed this case, the diagnosis is: Pigmented Purpuric Dermatosis