<s>[INST] I had a 12 cm lump show up on my inner upper thigh almost overnight and have no idea what it may be.I know my immune system has been very much activated by all the alternative things I have been doing for my advanced prostate cancer and was thinking possibly dead cells and poisens looking for a another way to exit my body.Is this an absurd thought? [/INST] Hello! Thank you for the query. Your though is not quite correct. Cancer cells do not get from the body in such way. As the lump has appeared quite quickly some abscess or hematoma are the most probable reason. In both cases there should be pain and swelling around this lump. The best way to find out what you are dealing with is an ultrasound. Abscess and hematoma should be incised and Chat Doctor. Hope this will help. Regards. </s>