Case Number : Case 2469 - 19 December 2019 Posted By: Saleem Taibjee

I think we r dealing with a recurrence yes, involving the surface epidermis but predominantly involving the follicular epithelium what is called: follicular malignant melanoma (in this case, it will be MIS with extensive follicular involvement). Waiting for beautiful IHC images! 

https://onlinelibrary.wiley.com/doi/full/10.1111/cup.12851

Difficult!  It could be an atypical actinic melanocytic hyperplasia...

Recurrente of LM with deep extension trought the follicular epithelium. Agree with Mona.

Agree on recurrent LM.

I would like to see SOX10 or MelanA to verify follicular involvement.

Yes, this is recurrent lentigo maligna, it is quite possible that the recurrence has arisen from persistent deeper follicular involvement. There also appears to be micro-invasion within the follicular involvement. My only hesitation in this case was the relatively bland cytology. However, the finding of PRAME positivity (overlying epidermis with positive control of sebaceous glands, then separate image of follicle) also supports melanoma. Melan-A and PRAME are shown below.

To be honest, I nearly missed the follicular involvement - it was only present in the tip of the specimen.

Mona, thanks for the useful reference which I was not aware of.

Festive greetings to everyone, back in touch after the New Year!

Saleem

additionally

Mona got the beautiful images. Nice case Saleem.