Use of Aldara mean it's not actinic keratosis or squamous cell

[rene74]

Dr. Rockoff,
   I thought I posted with correctly last night but I will try again.
   I am a 47 y/o female with a history of dysplastic nevi, melanoma in-situ (on chest), multiple basal cell and actinic keratosis.     My question is about a lesion that appeared on my chest about 6 weeks ago that I showed to my dermatologist stating I thought it was another basal cell and should I treat it with Aldara like the others on my chest that have been popping up alot since January of this year.  She agreed that I do that.  It started out about 5.5mm with a crusty scab in it.  That fell off and another scab developed on it.  The base of it was reddish and inflamed looking.  It appeared to grow about a millimeter in the six weeks I had it until it was biopsied today.  I usually really have a reaction when I treat a basal cell with the Aldara yet this lesion did not react and after two weeks I discontinued treatment and followed up with the derm and she finally biopsied it today which was about two weeks after I stopped the treatment.  Is that aldara treatment going to affect the diagnosis?  I just wanted it off.   I asked her what she thought it possibly could be and she said maybe an actinic keratosis.  I asked her if that is what squamous cell looks like and she said sometimes.  If it was an AK, or a superficial squamous cell, wouldn't it have reacted to the Aldara since I usually respond so well to it?  I worry it could be something more than even squamous cell!  The only raised part about it was the scab and it was all one color, red.  
  Thank you so much in advance!

[Alan Rockoff, MD]

I don't think the Aldara will affect the biopsy diagnosis.  You are right that Aldara would have caused an actinic keratosis to react.  I guess that's why your dermatologist wants to get a definitive biopsy diagnosis.  But again, the biopsy should tell you what you need to know.

Take care.

Dr. Rockoff