Other than by feel, how do you tell the difference between lipoma and regular fat - is there a special test that can determine if it is lipoma?

Lipoma : In order to have a definite diagnosis on what a lesion or mass is it would need to be taken out and get a biopsy. Depending on the size and location either a primary physician, dermatologist or surgeon can perform the procedure.

Lipoma: The most definitive way to tell whether a tumor underlying your skin is a lipoma is by taking it out and having a pathologist examine the tissue specimen. Ultrasonography (ultrasound) and radiography (x-ray, ct-scan) are by no means as reliable.