This thread will be interesting as there are so many little miscellaneous lumps and bumps all over the body that are hard to define.
This one is such a case, I am not sure what the diagnosis is going to be.
It is in the subcutaneous fat layer.
It looks to contain fat,
Could it simply be fat?
It does not look typical of fat necrosis , but this should get a mention.
AVM is another possibility, although I would not expect it to be that firm on palpation. Some AVM’s have lots of Doppler flow but others have very little.
Ingrown hair?
Epidermoid?
Let me know if you discover anything,
Steve