Case Number : Case 2824- 4 May 2021 Posted By: Uma Sundram

Absence of umbrella sign in an 80year old with sun damaged skin, i think its a Melanoma. I cant figure out the in-cohesive scatter.

Lentigo malligna melanoma. The invasive component seems to be desmoplastic but there are some epithelioid cells as well- so may a mixed type if not pure desmoplastic. There is also perineural invasion. 

Very nice demonstration of a "negative umbrella sign" suggesting a lesion of recent onset.  Also beautiful example of perineural invasion on H+E and MART1. Agree that the pattern of the invasive component is unusual - the forearm is not a common site for desmoplastic melanoma.

Yes, it's an amazing case of invasive melanoma, mixed type. Perineural invasion highlighted by MART 1.

Melanoma with regression

Invasive melanoma with perineural invasion