Infiltrating Lipoma in Right Lower Back Muscle.

Yes, excision of the lesion is indicated. An MRI study may be useful prior to the procedure. The choice of surgeon will be important.

Best wishes.

Lipomas generally produce pain in the local area. It is more out to cause pain if the lipoma extends into the muscle. The lipoma can be removed even if it extends into the muscle. The recurrence rate is low providing the whole lipoma is removed initially.

Although the VAST majority of Lipomas are benign (non-cancerous), a small minority may be malignant. For this reason we need to submit a piece of the lipoma for Pathology examination to learn its exact identity.
If you want to remove this fatty tumor, the best way to do it is to surgically excise it with its surrounding wall. The cost of doing so is a permanent scar BUT only in doing it in this fashion can you be assured that the entire mass was removed. While liposuction will flatten the area and leave smaller scar, it will leave bits of the lipoma behind and these may eventually come back.
Dr. P. Aldea

There is a variant of the common lipoma which is called an infiltrating angiolipoma. The fact that you describe you lipoma as infiltrating leads me to think that you have had an MRI indicating that you have this type of tumor.
The infiltrating angiolipoma usually affects the area around the vertebrae, and sometimes the lower extremities (besides the well known angiolipoma of the kidneys).
Or you may have a more cellular variety of the common lipomas which can infiltrate into the muscle. Clinically, they can be differentiated by tenderness: the infiltrating angiolipoma can be quite painful while the regular lipoma which is infiltrating into the muscle is not.
The surgeon will most likely have to sacrifice some of your muscle to ensure total resection of your lesion. If this is done adequately, you will not have a recurrence.
I agree with Dr. Rand, that the sooner the better. It will be easier on both you and your surgeon.
Incidentally, I had a very cellular lipoma removed from my left shoulder about twenty years ago. Mine had infiltrated into the muscle and I use its removal as an excuse for my failure to develop prodigious muscles like that other Arnold.

Definitely do not consider liposuction for what you have.  A preop CT scan or MRI can determine if there is muscle infiltration or not.  An open surgical excision by an experienced surgeon is required and the relatively sooner the better so it doesn't continue to grow.