Case Number : Case 2477 - 2 January 2020 Posted By: Saleem Taibjee

Reminds me of something we published in the vulva a while ago.

Perianal Bronchogenic Cyst?

Benign mucinous metaplasia

Agree, benign mucinous metaplasia. I don´t see any atypia for a bowen disease plus metaplasia. Nice case, I have never seen this diagnosis.

Yes. Agree with Mona. I didn’t know this. 

On 02/01/2020 at 15:10, Dr. Mona Abdel-Halim said:

Benign mucinous metaplasia

 

Agree. Never seen before.

Yes, well done, this is mucinous metaplasia. The Alcian blue stain is shown below.

I first became aware of this from a case which Richard Carr had co-authored: Extensive mucinous metaplasia of the vulva
arising within Zoon’s vulvitis. British Journal of Dermatology 2007;156:748–91.

This has also been reported on the penis. However, this is the first such case which I have come across on perianal skin. I reported the case as a backlog case for another hospital, but have not heard further from the clinician.

Funnily enough, after submitting this case, just last week I came across another example of focal mucinous metaplasia arising in a background of balanitis xerotica obliterans the in my routine pile! Some images also follow below.

BW Saleem

Here is another useful reference which I forgot to include earlier:

Boer-Auer A, et al. Benign mucinous metaplasia of the genital mucosa: histomorphological and immunohistochemical features and criteria for differentiation from extramammary Paget disease. British Journal of Dermatology 2011 165;1263–1272

I guess this is a progression from Zoon's. Needs a dermatologist to assess for underlying irritant or lichenoid dermatosis including lichen sclerosus & lichen planus etc.

Nice case Saleem and nice to see the paper getting a mention!