subungual melanoma / melanonychia

Hi

Hope somebody can help with advice. About a month ago I noticed a light black streak on my thumb.

I saw a dermatologist who used a dermascope to examine the nail. The consultant wasn't too worried and was happy to wait and see if it got worse, but also offered a biopsy.

Being worried I went for the biopsy. The entire thumbnail was removed, when the surgeon pulled back the skin behind the cuticle no lesion was present, he was confident it was completely fine but I insisted on the biopsy so a random sample was taken, which came back normal.

I recently saw the dermatologist again as a couple more lines have appeared one on the other thumb and one on the index finger of the same hand as the original  thumb streak.

While there he also looked (dermascope)
at the healing thumb. The nail has partly regrown one month on.

He said he could see pigment again, but seeing as I had now developed other streaks he would be inclined to think it was more likely be racial longitudinal melanonchia (I am dark skinned).

My research had led me to believe that you could get longitudinal melanonchia either due to melanocytic activation or melanoncytic hyperplasia. The latter (hyperplasia) causing a mole or lesion.

I didn't think there HAD TO BE a mole or lesion, to cause the black line (melanonchia) and it was just pigmentation in the nail.

However when I reminded the dermatologist that no lesion was visible when the surgeon removed the nail he (the dermatologist) implied there had to be a mole or lesion to cause the line.

So he said either we had to be happy with the result of the biopsy or assume the surgeon missed the right area as nothing was found and repeat it again on the same thumb. Again he was happy to wait and see and wasn't worried.

Questions:

Is longitudinal melanonchia always caused by a mole or lesion regardless of whether it is benign or malignant?

Can anybody suggest the name of a consultant who specialises in longitudinal melanonchia / subungual melanoma.

Also would I be right in thinking that if there was a lesion it would start just below the skin behind the nail cuticle and work down rather than the other way round i.e. start deep in the finger/thumb and work its way up to the surface

Also are there any nutritional reasons for it.

Any help would be appreciated.

Yours
Very stressed.