Case Number : Case 2154 - 11 September 2018 Posted By: Uma Sundram

Actinic keratosis. Would like to do Melan A, just in case....

Malignant Melanoma, sperficial spreading type, II Clark level. 

LM or LMM.  Obscured by inflammation.  Sox10 to assess dermis

Thanks for posting this case Uma! Nevi on the ear are very confusing to me. Some publications suggest that benign nevi on ear can have very atypical features, while some authors believe that these are probably melanomas (can quote exactly when I access David Elder's AFIP book on melanocytic lesions when I get to my office tomorrow). I often send these cases for more studies such as gene-expression based Mypath melanoma test by Myriad Genetics. Without such tests I would classify the above lesion as a melanoma, because of its architectural disorders and upward spread.

Agree, melanoma for me too

This is a very difficult case. My biggest concern would be the atypical features on the ear in a 65 year old male. Lesion is MART1 and SOX10+. My former mentor, Sabine Kohler, used to have a very high threshold for calling melanoma in special sites, and would call them all nevi, even in older individuals. I, on the other hand, had one of these lesions recur, so am convinced that if the atypia is striking, these lesions should 1) never be called nevi and 2) always be treated conservatively. This is especially true of individuals over the age of 50. Sun exposed sites, such as the ear, are particularly problematic, which is why I chose this case. In this case, because of the size of the lesion (it was less than 0.5 cm), we stopped short of melanoma, but suggested conservative treatment to ensure complete removal of this markedly atypical lesion.

Agree atypical thin Spitzoid lesion on special site. Thin MELTUMP low risk for metastasis. Watchful waiting if out or modest re-excision are both options given close margin.