Case Number : Case 1910 - 25 Sept - Dr Limin Yu Posted By: Guest

Acquired perforating disorder

Agree with Anil.    There are 4  perforating disorders, usually diabetes-associated: Kyrle's disease, perforating folliculitis, elastosis perforans serpiginosa, and reactive perforating collagenosis. I think this perforating material is collagen, so favor acquired reactive perforating collagenosis. But I'm not able to distinguish between Kirle's disease and ARPC. CPC is important of course.

 Very nice case.

The pictures are fantastic. Agree with the colleagues, acquired perforating dermatosis, probably acquired reactive perforating collagenosis for CPC.

Very nice example of perforating dermatosis, likely RPC as transepidermal elimination of collagen can be seen in some of the photos.

Relatively straight to Spot diagnose but no so easy to treat.

Agree, perforating collagenosis. Lovely pictures!

The last image shows vertically orientated light pink collagen (I think) in the centre and I'm pretty sure I can see some subtle more basophilic collagen in the crust too (polarising microscopy or trichrome will show it nicely - not required). The slender darker pink (hmm I'm struggling for the best colour for elastic fibres!) are elastic fibres. Collagen is a lighter pink than elastic (perhaps "bubble gum" pink). The elastic fibres are wavy in the dermis but often look vertical and straighter when perforating. The basophilic change to the collagen and neutrophils in the crust is highly typical of perforating collagenosis. EVG will show the elastic but again not sure it's required here.

Thank everyone for insightful discussion. I agree with all of you. This is a perforating disease and acquired reactive perforating collagenosis is the diagnosis. 

I emailed trichrome stain images to Admin. He/she didn't post them, I guess, not to make it too straightforward.  The stain shows the blue colored collagen perforation.  Unfortunately I can't attach the image file in this reply due to the low limit of file size (less than 0.11 MB) in attachment. 

Thanks!