My 18 yr old daughter just showed me a small lump under her armpit that is painful to touch.  It has a black spot in the center. she said it has been there for a long time, but she noticed the black spot is larger, lump is the same size.  What could this be?  Hopefully not cancer?
Hi. Thanks for your query and an elucidated history. Why do you suspect cancer in a girl of just 18 years old. This is by far not known to have cancers in this age group. This is a classical sebaceous cyst and excision by a Surgeon is the best way to get the lump cured.