Is this mole dangerous?

I have always had this round mole like birthmark on my arm.  When I was a young child it was small.  I could cover it up with a dime.  It has been a slow process, but over the years it has not only grown in size, but has become raised.  It is soft to the touch and squishy.  I have spent a lot of time in the sun over the years.  It does grow black coarse hair - that I have to shave off.  It is about 5.5cen. x 7.5cen. in size.  When I work out it sweats more than the rest of my body.  Long after I cool down it will still have beads of sweat that drip off and I am constantly wiping off the sweat...  I have questions about it.  Is it a mole?  Is there a chance that it will ever turn cancerous?  Is it going to continue to grow.  My worry is that if it's puffing up, is it rooting down?  Should it be removed?  If I remove it, can it grow back?

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[Vanessa Lacuesta]

Firstly , this does not sound like skin cancer. The skin condition has been present since birth and moles do change as one grows. Moles are affected by hormones and as one grows the mole also changes in size and appearance. I advice that you refrain from shaving the hair. This may accidentally cause a cut or nick on the skin's surface. I suggest that you seek consult with your physician so that this will be assessed. Some forms of laser therapy may help decrease or delay hair growth in the area. Hair in moles is a sign that this is a benign lesion. Skin cancer destroys cells that help generate hair. So this is a good sign.

Some moles however, may not present similarly as other moles. A differential will be an atypical nevus:

"Larger than normal moles (more than a half inch across), atypical moles are not always round. Atypical moles can be tan to dark brown, on a pink background. These types of moles may occur anywhere on the body. "

Source:http://www.umm.edu/dermatology-info/other.htm

The url above has a nice discussion on how to assess changes in a mole. If these changes are present, then I suggest that you seek immediate consult.