If your puppy has a lump it needs to be needle aspirated, with the sample sent off to a Pathology lab. Sometimes a Vet can see fatty globules on the slide, and make a diagnosis of a fatty tumor. But outside of that it should be read by a Pathology lab. What a Vet can not do is just feel or look at a lump and make an accurate determination as to what it might be.

Since the growth has been present for a year it is most likely to be a cyst, or a non-malignant Fibrosarcoma. Although one can not eliminate a very slow growing Hemangiopericytoma. Again your friend needs a sample sent off to a Pathology lab.