In our case, diffuse osteopenia with osteolysis of phalanges on both
sides and osteoporotic change in vertebrae was observed but no
osteolytic lesions were seen in axial skeleton, unlike in MM, which is
characterized by the presence of osteolytic lesions of the axial
skeleton(2,3).
Plasma cells express osteoprotegrin (OPG) which blocks the interaction
between RANKL and RANK receptor on osteoclast surface leading to
impaired osteoclast resorption and preservation of bone structure(2).
Unfortunately, OPG levels could not be investigated in our patient.
SSc treatment includes non-steroidal anti-inflammatory drugs,
corticosteroids and immunosuppressants such as methotrexate,
azathioprine, mofetil mycophenolate, and cyclophosphamide. Nintedanib,
an antifibrotic agent, tocilizumab, an anti-interleukin-6 receptor
antibody, and rituximab, an anti-CD20 antibody were approved for
interstitial lung disease related to SSc and had showed improvement in
both modified Rodnan skin score(17).
Thalidomide is used for the treatment of MM, as it acts as an
anti-proliferative, antiangiogenic and inhibits myeloma tumor growth
(15-17). The previously reported cases showed that systemic sclerosis
symptoms were improved greatly by the treatment used for MM (when the
two conditions were associated) (18).
In our case the patient showed a substantial improvement of her symptoms
after 6 months of MM treatment