Case Number : Case 890 - 15th November Posted By: Guest

Desmoplastic Trichoepithelioma

May i add morpheic BCC to the DD

I favor columnar trichoblastoma over morpheaform basal cell carcinoma because this well-circunscribed lesion has a depression in the center of its surface. Also I didn't find solar elastosis below the lesion.

I favour an infiltrative basal cell carcinoma. There is peripheral palisading (the first photo), retraction artifact and absence of horn cysts (although there is a foreign-body giant cell in the third photo). What does CK20 show?

Infiltrattive BCC
CK20 is usually positive in TE and not BCC
BCL-2 and CD10 ARE usually positive in THE BASALOID cells OF BCC and not TE( only the basaloid cells of the periphery of TE will BE cd10 POSITIVE

Nice tricky case.
It is going to come down to a vote of infiltrative BCC versus DTE.
I favour DTE here based on criteria including overlying dell, quality of stromal reaction, granulomatous reaction. However, there does seem to be increased mucin, and immunos might sway me either way i.e. Merkel cells or otherwise.

on first impression I thought DTE. However looking at the pics closely, there does seem to be a retraction artefact around the nests favouring a BCC. Also in the first pic towards the top right edge, I think Richard might be hiding the superficial BCC component of the tumor!. It is suspicious of that anyway. However, I agree that immunos would be helpful.

Having said that, I believe that BCC and DTE are children of the same mother! They might have a different father though

Infiltrative BCC.

Syringoid eccrine carcinoma

infiltrative BCC

I have asked the dermpathpro team to post the IHC at 4pm GMT. I am the father of this case by the way. Another father (of dermatopathology) once said the diagnosis of DTE is one of the most difficult in dermatopathology.

[quote name='Dr. Richard Carr' timestamp='1384517030']
I have asked the dermpathpro team to post the IHC at 4pm GMT. I am the father of this case by the way. Another father (of dermatopathology) once said the diagnosis of DTE is one of the most difficult in dermatopathology.
[/quote] who is the mother?

Dear All, please view the case of the week if you have a moment - it is a new feature of the site and we hope it will generate some discussion.

[quote name='Iskander H. Chaudhry' timestamp='1384519240']
Dear All, please view the case of the week if you have a moment - it is a new feature of the site and we hope it will generate some discussion.
[/quote]
Please post the link and include the link in the blog menu/ home page Iskander. Can't find it!

Favour infiltrative BCC,,,, waiting for the immunos!!

The presence of large epitelial islands, considerable nuclear atypia in some foci, retraction artifact and lack of concentric bands of collagen enveloping elongated epitelial strands favour morpheaform BCC.

Dear All, you can access the case of the week from the home page or by clicking on the link below:

[url="https://dermpathpro.com/case_of_the_week.html/_/case-1-r3"]https://dermpathpro.com/case_of_the_week.html/_/case-1-r3[/url]

[img]https://dermpathpro.com/uploads/spot_diagnosis_comment_img/CASE890_RAC6317x10_CK20_MR.jpg[/img]





[img]https://dermpathpro.com/uploads/spot_diagnosis_comment_img/CASE890_RAC6316x5_BerEP4_MR.jpg[/img]





[img]https://dermpathpro.com/uploads/spot_diagnosis_comment_img/CASE890_RAC6316x20b_Ki67_MR.jpg[/img]




[img]https://dermpathpro.com/uploads/spot_diagnosis_comment_img/CASE890_RAC6316x10b_Bcl2_MR.jpg[/img]




[img]https://dermpathpro.com/uploads/spot_diagnosis_comment_img/CASE890_RAC6316x10_CD34_MR.jpg[/img]




[img]https://dermpathpro.com/uploads/spot_diagnosis_comment_img/CASE890_RAC6316x10_CD10_MR.jpg[/img]

Waaaaaaaaaaao !!!!!!
As I expected,,,,, beautifully demonstrated immunos....
I love this :-))

infiltrative BCC

Because there is nuclear pleomorphism, some nuclear palisading and retraction artifact, I favor infiltrative BCC. Of course, the classic differential includes DTE, but the stroma and the cytologic features don't look great for it, and MAC, for which I don't see the classic stratification, with keratocysts on top. I would still perform IHC to rule these two out.

Oops, immunohistochemistry changed my mind. It's basal cell carcinoma.

Mona you just made my day! Yes it is a basal cell
[quote name='Romualdo' timestamp='1384527431']
The presence of large epitelial islands, considerable nuclear atypia in some foci, retraction artifact and lack of concentric bands of collagen enveloping elongated epitelial strands favour morpheaform BCC.
[/quote]
Says it all - IHC is helpful if you have any doubt. Merkel cells limited to trapped follicles (and perifollicular dermis). Ki67 is nearly 50% (should be ~5% in DTE). BerEP4 just highlights the abnormal larger irregular foci not allowed in DTE. Remember DTE has the nice curvilinear cords only 2 to 3 cells in width although this case does have some cords mimicking the pattern closely. Dr Bernard Akerman was the father of dermatopathology who said DTE can be one of the most difficult diagnoses in dermatopathology.

On H&E, additional features that suggested infiltrative BCC was the definitive mucinous stroma surrounding nests in the lowest high-power photo, and presence of mitotic activity and/or hyperchromatism in the same.

The immunostains in this case are neat and nicely light up the diagnosis. Another marker I got to work with these days is TDAG51, a follicular stem cell marker that reliably differentiates between trichoepithelioma and BCC. For similar cases, usually a panel made of TDAG51 and BerEP4 is enough to put one on the right track.