Hmmm...I would want to investigate "other possibilities." I was diagnosed in September with "osteonecrosis of the left femoral head and neck" via MRI without contrast. In February I recieved my diagnosis of "pleomorphic lobular carcinoma with neuroendocrine features." ER (95%) and PR (70%) positive HER2 negative, Ki67~70%(Pathology went to Cleveland Clinic for second opinion.) Tumor size by ultrasound 3.1 cm, initially grade III. Started letrozole and Ibrance on March 2 & March 9 respectively to shrink the tumor and halt disease progression prior to CT scan and surgery.

CT scan showed this:

MUSCULOSKELETAL ABDOMEN PELVIS: Mixed lucent and sclerotic appearance of the
anterior aspect of the left femoral head, with slight cortical collapse, in
keeping with osteonecrosis. No right femoral osteonecrosis. Slight leftward
curvature in the lower lumbar spine. Severe disc degeneration at L3-4 and
L4-5. Small densely sclerotic foci in the right iliac bone are almost
certainly bone islands.

Of course, I already had a comparison MRI and diagnosis. My onco and radiologist were not concerned about the "lytic and sclerotic lesions". So..this could be and example of the "other possibilities" that could masquerade as bone mets.

I am 69. Had lumpectomy on April 5, reexcision (only to find NOTHING) on April 19. Lymph node negative. Currently on an Ibrance holiday until after radiation (15 whole breast 5 targeted to tumor site). I start Ibrance again in July for a year...(😪) Letrozole probably for 10 years.

I would never venture to discount a Cleveland Clinic tumor team, but they do look at everything through a cancer lens, which might cause them to rule out the other possible reasons for those sclerotic lesions. My husband had a bone biopsy when he had prostate cancer that showed healed trauma from a slip on the ice and subsequent contact with the brick steps when he was in high school. Not a fun way to confirm what he already told the docs.

My post surgical tumor size was 2.3 cm. The Ibrance/letrozole was effective in shrinking the tumor by 20% in just one cycle. I fully expected to be stage 4, but my current stage, (according to the radiologist) is IB...

I hope this helps a little. Feel free to contact me privately.