Case Number : Case 1541 - 20 May Posted By: Guest

Large cell acanthoma. 

Yes agree, large cell acanthoma. Probably a variant of solar lentigo as it is stated since some time http://www.ncbi.nlm.nih.gov/pubmed/24917472

Large cell acanthoma

large cell acanthoma

My report:

Slightly pigmented large cell acanthoma. No frank dysplasia.

I agree from personal experience that they often appear to be closely related to solar lentigo (all be it the "keratosis" outweighing the pigmentation).  The point is they are rather subtle and nice to have in your diagnostic armamentarium. I have always discussed with dermatology colleagues that solar lentigo is on a spectrum with thin seborrhoeic keratosis (and not a lentiginous melanocytic proliferation at all). In that sense LCA and thin seborrheoic keratosis are not really alike as the former is composed of larger and paler keratinocytes without significant cellular hyperplasia compared with the latter. Perhaps LCA is worth keeping as a separate entity.

Slightly radical thought, perhaps solar lentigo should be renamed pigmented LCA! and reported as follows:

Pigmented large cell acanthoma (formerly known as solar lentigo).