Plasmocytoma: Diagnostic Tests

Mandatory medical device diagnostics.

  • Radiograph of the skull, thorax (radiograph thorax in two planes), pelvis, skeleton (here: humeri/upper arm bones and femora/thigh bones), and if necessary of the sternum (sternum) and ribs; spine in 3 sections, each in 2 planes – to exclude osteolysis (spatially circumscribed dissolution or degeneration of bone tissue) [skull image shows typical “shot skull”; in the early stages occasionally inconspicuous]Note: The contrast agent-free whole-body computed tomography in “low-dose” technique is superior to conventional X-ray imaging in terms of sensitivity and specificity.

Optional medical device diagnostics – depending on the results of the history, physical examination and obligatory laboratory parameters – for differential diagnostic clarification.

  • CT, MRI, and PET-CT are superior to conventional imaging:
    • Computed tomography (CT): whole-body CT (low-dose CT); indications:
      • Detailed examination of the bones for early detection of osteolysis, assessment of the stability risk of osteolysis, or differentiated fracture diagnosisNote: Approximately 20% of patients who are unremarkable according to X-ray already require therapy due to osteolysis on CT.
      • For planning radiotherapy
    • Magnetic resonance imaging (MRI) of bone marrow-forming structures; indications:
      • In cases of suspected bone marrow infiltration and/or compression of the bone marrow.
    • If necessary, positron emission tomography/computed tomography (PET-CT); combined nuclear medicine (PET) and radiological (CT) imaging procedure in which the distribution pattern of radioactive substances (tracer: here: 18-fluorodeoxyglucose (18F-FDG)) can be localized very precisely using cross-sectional imaging techniques)Note:
      • The sensitivity of PET and MRI is mostly comparable, but MRI seems to have an advantage in detecting diffuse involvement.
      • PET may show false-positive lesions, which may be inflammatory, infectious, or postoperative.
      • PET can also be performed in renal insufficiency.

Further notes

  • Skeletal scintigraphy is not suitable for detecting bone manifestations because osseous (“belonging to the bone”) plasmacytoma foci do not store the radioactive markers.
  • At the time of diagnosis of plasmacytoma (multiple myeloma), MRI and PET-CT (see above) provide comparable findings (MRI: 95%; PET-CT: 91%). At the start of maintenance therapy, PET-CT showed normalization in 62% of patients, whereas MRI showed normalization in only 11%.Further results of the study show:
    • Normalization in PET-CT during the further course of therapy represents an important prognostic variable.
    • Patients with negative MRD findings and normalized PET-CT before maintenance therapy have a particularly favorable disease course.