Desmoplastic trichoepithelioma

Clinical features

•Asymptomatic, slowly growing less than 1.0 cm white or yellow lesion with a predilection for the cheek, chin & forehead 

•Lesions are indurated and the extent is difficult to delineate clinically similar to microcystic adnexal carcinoma)

•Asymptomatic

•Does not ulcerate

•Rarely multiple

•Often associated with a central dell

.4F=1M

Histological features

•Consists of narrow epithelial strands & keratocysts embedded in a dense stroma

•Generally involves superficial & mid dermis but does not extend into the subcutaneous fat

•No evidence of glandular differentiation

•Calcification, foreign body giant cell reaction to keratin & bone are inconstant findings

•Epithelial stands may arise from follicular epithelium

•Can rarely see matricial differentiation

•CK20 highlights Merkel cells

•Perineural infiltration is documented but is exceptional & makes differentiation from MAC difficult

•Co-existence with a dermal nevus is sometimes encountered

. EMA & CEA show no evidence of ductal differentiation

BerEP4
CD10
CK20 positive Merkel cells
CK20
Desmoplastic trichoepithelioma with co-existing dermal nevus
Keratin stain highlighting perineural infiltration
Keratin stain highlighting perineural infiltration

2 responses to “Desmoplastic trichoepithelioma”

  1. marietjievaswegen avatar
    marietjievaswegen

    Dear Prof McKee, This must be a labour of love! Thank you so much for these blog posts – they are the highlight of my day and of immeasurable value! (I have tried to like them on the website – but will have to create an account first)

    I am a young dermatologist in private practice in South Africa with an interest in dermpath. As you know, it is not (yet) regarded as an entity in SA. I have had the pleasure to attend your lectures arranged by Dr Wayne Grayson and I have spent some time at the ISDP training centre in Pilsen with Prof Michal and Prof Kazakov.

    I am involved in training of our dermatology registrars at the university of the Free State and have strongly advised them to subscribe to your blog posts. Thank you for making dermpath seem so easy and giving us access to your wealth of knowledge.

    May you have a lovely day. Warmest regards Marietjie van Aswegen

    >

    Liked by 1 person

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    1. Phillip McKee avatar
      Phillip McKee

      Thank you so much. A lovely message. They are a labour of love!!

      Liked by 1 person

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