Does a positive Melan A stain on a pathology report equal a melanoma?

Question

I recently had a shave biopsy and am a bit confused by the pathology report. The final diagnosis is atypical junctional melanocytic proliferation. The pathologist noted that immunoperoxidase analysis and multiple level sections were examined, and a markedly irritated dysplastic nevus (moderate to severe atypia) is favored. It then notes that it is Melan A positive. I am curios about the stain being positive, yet the final diagnosis being atypical melanocytic proliferation. Thank you for advising!

Nelson Castillo, MD · Answer

Thank you for your question.  Always best to have the surgeon who removed the biopsy explain your pathology results in order to provide you with reassurance or the recommended treatment plan, but Melan A stain is used to identify cells of the melanocytic lineage (the pigment producing cells) and can be found in both melanomas as well as non-melanoma moles.  Because dysplastic nevi are thought to be precursors towards melanoma your surgeon will likely favor excision - removal - of the mole in its entirety.  Hope this helps.

Arlo J. Miller, MD, PhD · Answer

Melan-A is a protein found in melanocytes (pigment producing cells) as well as a few other cell types (which aren't in the skin).  It will be found in normal melanocytes that you'd see in completely normal moles and it will be found in most, but not all melanomas.  Antibodies to Melan-A are used to identify melanocytes in pathology specimens-basically to help make sure that what they think are melanocytes really are melanocytes.  Sometimes they may also be looking at whether the cells are losing Melan-A.  So, whether the stain is + or - truly does not equate to whether or not its melanoma.  It really is better to think of it as an additional tool that they can whip out and use if the diagnosis is not a slam dunk.We wish that when we sent in specimens we'd get a clear cut answer.  Is this melanoma or not?  Seems easy, right, sort of like asking is that a butterfly or a bird?  Many times, though, its a lot more like asking, "Is that a Monarch or a Viceroy butterfly?"  If you know your butterflies well, you can tell them apart.  But nature's not perfect, so what if you had a freakishly ugly orange butterfly that's old, survived an encounter with a sparrow and has whatever the butterfly equivalent of buck teeth and bow-legs; and you had to figure out, "Is that a messed up Monarch or a messed up Viceroy butterfly?"When pathologists render a diagnosis, the pathologist is taking a lot of factors into account, such as the appearance of the cells; including their size, shape, what their nucleus looks like, what their cytoplasm looks like; as well as the way the cells are grouped in the skin-sort of like whether they are symmetric, asymmetric, crazy.....  Then, they can also look at staining patterns with antibodies like Melan-A/Mart1, another one called HMB-45, and another one called MITF.  There are even more tests beyond these that can be done when necessary.

Does a positive Melan A stain on a pathology report equal a melanoma?

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Does a positive Melan A stain on a pathology report equal a melanoma?

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Everything you need to know about Mole Removal

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