My uncle is having various health problems that are being diagnosed. He just had a knot pop up on his shoulder and has one on his stomach as well.  Doctors are checking him for possible liver cancer (spot seen after a scan with contrast and xrays).  Hes also in pain with pinched nerve, hernia, and possible ulcers. I had heard that various cancers can cause knots under the skin.  Any ideas?
Hello dear, thanks for your question on Chat Doctor. Yes, you are right about cancers giving not under skin. It is known as spread of cancer in the skin. And many cancers cause this. The common ones are liver, lung,kidney and breast cancer. So possibility of cancer spread in skin in your uncles' case is high as He is having liver cancer. So better to get done biopsy of the skin lesion and get done histopathological examination to diagnose its cause. If it is malignant than your uncle is having stage 4 liver cancer. And it is having poor outcome.