Severe Abnormal Mole vs. Melanoma in situ

Posted By
11/8/2018 9:31am
Replies: 4

I need some clarification. I had a mole shave (not punched) biopsy from my back by a dermatologist in September 2018 and her pathologist diagnosed it as a "Severe abnormal mole." I decided to go to a second dermatologist where I had it completely excised and received clear margins. Nothing alarming came back on the pathology report after the second dermatologist excised it, they just told me it was gone. The second dermatologist then had their pathologist (who only looks at skin apparently) review the initial slides of the shave biopsy and he diagnosed it as "Melanoma in situ." I'm not sure who/what to believe. It sounds like a difference of opinions with the pathologists. It doesn't change the was completely excised, regardless, and I need to watch myself closely and do 6 month follow ups. Right? I’m just confused as to why one pathologist would call it severe abnormal mole and one would call it melanoma in situ. Is there a difference?

Pathology is not an exact science.  Think of it on a scale.  You look at maybe 10 different factors.  One pathologist sees 6 factors he think are not cancer while the second sees 6 he thinks qualify as cancer.  They look at all the different aspects based on their experience and make a final determination. If you have another opinion, it might be either diagnosis.   Typically we prefer using dermatopathologists to read slides because skin is all they do.  A general pathologist would not likely see as much melanoma.  Having said that, some pathologists may be overly aggressive in saying something is melanoma to cover themselves.  Erring on the side of worst diagnosis rather than the other way around. 

Regardless of the diagnosis, both severely atypical lesions and melanoma in situ should both be excised with 5mm margins - for the very reason that there can be differences in interpretation.  If you had the wide excision with 5mm margins, you're good to go.  Differing opinions on pathology isn't uncommon but I wouldn't stress about it at all.  It's removed and you now move on.

Anonymous - (11/8/2018 - 4:05pm)

Thank you very much! I was curious if the lesion had Breslow thickness or depth of invasion. The nurse claims when they excised it, it did not. This was the only thing I was hung up on...if I still need some kind of lymph node biopsy. She said the initial shave biopsy slides showed "Superficial Melanoma."

By definition, in situ has no depth.  In situ is confined to the epidermis.  Breslow depth is the measure when the lesion becomes invasive and penetrates the dermis.  It is measured from the epidermal junction into the dermis and does not include the actual epidermal tissue.  The nurse probably said "superficial spreading" melanoma - that is the most common type of melanoma.

Anonymous - (11/15/2018 - 9:49am)

It appears there is a lot of debate and gray area when dianosing a mole as severe or Melanoma in situ. Biopsy results can differ worrying patients and there isn't one clear standard shared by everyone. Also, there is a lot of debate on whether or not in situ is cancer or pre-canerous cells. There's a lot of debate about whether or not it will come back in a different area or will never come back. At least this has been my experience and what I have found through research. It makes it very confusing for the patient.