Case Number : Case 2742 - 8 January 2021 Posted By: Richard Logan

dermal sclerosis, vascular damage with panniculitis

could it be dego's disease, CPC needed

Did you do a Congo red to rule out amyloid?

Wedge shape ulceration and dermal hyalinization. I´m think Degos it´s a good possibility.

Is this just a single lesion, any other vasculopathy history?the images are a little blurred on my useless laptop, any calcium in the vessel ealls. i would do a mucin stain and congo red

?Amyloidosis. 

This is an example of radionecrosis.  The patient had previously had a non-melanoma skin cancer on the side of her knee treated with orthovoltage radiotherapy some years previously.  The histology is rather bland and uninteresting with a washed-out, hyalinised dermis, devoid of adnexae, and abnormal dilated blood vessels.  Presumably the scarring following radiotherapy damages the blood supply.  The epidermis becomes hypoxic, necroses, ulcerates and is replaced by an eschar. 

Typically if a patient who has had radiotherapy develops an ulcer at the site, in my experience it is more likely to be due to radionecrosis than recurrence of the original tumour, especially if the lesion is painful. 

Radionecrosis is much more common on the distal limbs such as here rather than on the trunk, head or neck, which is why Radiotherapists try to avoid treating these areas.  With the increase in surgical skills of dermatologists over the last 30 years or so, radiotherapy is much less often used to treat common skin tumours, so cases like this are becoming less common, and almost always arise in older patients.

There is one other example of this phenomenon on the website, a rather better example in fact.  It was posted by Saleem Taibjee on 28th November as case 2454.

Radionecrosis.docx

Nice case Richard

Nice case!