Plasma Cell Disorder
| A | Heavy chain disease | |
| B |
Monoclonal gammopathy of undetermined significance |
|
| C |
Multiple myeloma |
|
| D |
Plasmacytoma |
Biopsy of a reasonably well-demarcated mass of the nasopharynx from a 30 year old man, Kapoor, demonstrates a plasma cell proliferation. Serum electrophoresis shows a small monoclonal IgG spike. Bone marrow evaluation fails to demonstrate plasma cell proliferation and no lesions are seen on extensive skeletal x-rays. Which of the following is the most likely diagnosis?
| A |
Heavy chain disease |
|
| B |
Monoclonal gammopathy of undetermined significance |
|
| C |
Multiple myeloma |
|
| D |
Plasmacytoma |
Plasmacytoma (solitary myeloma) involving soft tissue (lungs, nasopharynx, nasal sinuses) is a plasma cell proliferation resembling multiple myeloma but without significant metastatic potential.
In contrast, some plasmacytomas involving bone eventually (up to 10 to 20 years) develop into frank multiple myeloma.
| A |
Multiple myeloma |
|
| B |
Indolent myeloma |
|
| C |
Monoclonal gammopathy of unknown significance |
|
| D |
Waldenstorm’s macroglobulinemia |
Answer is C (Monoclonal gammopathy of unknown significance)
‘Patients with monoclonal gammopathy of uncertain significance have < 10% bone marrow plasma cells, and < 3g / dl of M component’,
Presence of 8% bone marrow plasma cells and 1.5 gm/dl of M component in the form of IgG in this patient thus lead us to the above diagnosis.
Plasma cell dyscrasia : Monoclonal gammopathies : Paraproteinemias : dysproteinemias
These are monoclonal neoplasms characterized by expansion of a single clone of immunoglobulin secreting cells (plasma cells) and result in increase in serum levels of a single homogenous ‘immunoglobulin’ or – its fragments (light chains or heavy chains).
The most important differential diagnosis in patients with multiple myeloma involves their distinction from individuals with MGUS or Benign monoclonal gammopathy:
|
Parameters |
Multiple myeloma |
Monoclonal gammopathy of undetermined significance |
|
I. Age Q |
> 50 years |
> 50 years |
|
2. Incidence Q |
Less common |
More common |
|
3. Plasma cells Q (%age) |
> 10% |
< 10% |
|
4. M component Q (concentration : g/dl) |
> 3g/dl |
< 3g/di |
|
5. Benze Jones Q proteins |
Present |
No urinary Bence Jones proteins |
|
6. Clinical features Q |
Lytic bones lesions Hypercalcemia Renal failure Anemia |
No Lytic bony lesionsQ No hypercalcemiaQ No renal failuree No anemiae |
|
7. Labelling index Q (Thymidine) |
> 1% |
< 1% |
|
8. Plasma cell – acid phosphatase – glucoronidase |
High High |
Low Low |
|
9. Treatment |
Required |
No therapy required |
Woldenstorm’s macroglobulinemia: is also a monoclonal gammopathy and is characterized by neoplasm of lymphoplasma cytoid cells that secrete IgM
M component is only IgM and not IgG.
| A |
Multiple Myeloma |
|
| B |
Plasmacytoma |
|
| C |
MGUS |
|
| D |
Smoldering Myeloma |
Answer is A (Multiple Myeloma):
Plasmacytoma on tissue biopsy and Bone marrow plasmacytosis with >30 percent plasma cells are two major criteria for the diagnosis of Multiple Myeloma. Presence of ant’ two major criteria is believed to confirm the diagnosis of multiple myeloma.
The clinical complex of bone pain and renal failure together with diagnostic observation of skeletal destruction, hypercalcemia, monoclonal ‘Al’ spike, tissue plasmacytoma and bone marrow plasmacytosis >30 percent confirms a diagnosis of Multiple Myeloma
MGUS is typically associated with < 10 % plasma cells on bone marrow biopsy.
Solitary Plasmacytoma and Smoldering myeloma are by definition/criteria not associated with any myeloma related symptoms (Anemia, Hypercalcemia, and Renal Failure)
| A |
Multiple Myeloma |
|
| B |
Plasmacytoma |
|
| C |
Smoldering Myeloma |
|
| D |
Lymphoma |
Answer is B (Plasmacytoma)
Presence of a solitary lytic lesion of the bone with monoclonal plasma cells suggests a diagnosis of Solitary Plasmacytoma of Bone. A small M spike may be identified in some patients but Bone Marrow biopsy taken some distance away from the primary site is typically not involved typically showing < 10 percent plasma cells
Solitary Bone Plasmacytoma
The diagnosis of SBP requires histologic evidence of a monoclonal plasma cell infiltrate in a single bone lesion, absence of other bone lesion on skeletal survey, and lack of marrow plasmacytosis elsewhere. Furthermore, there should be no evidence of anemia, hypercalcemia, or renal dysfunction that could be attributed to the plasma cell proliferative disorder spike may be identified in some patients hut Bone Marrow biopsy taken some distance away from the primary site is not involved typically showing < 10 percent plasma cells.
Diagnostic criteria for Solitary Plasmacytoma of bone and Extramedullary Plasmacytoma
- Solitary Osseous lesion or Extramedullary lesion due to clonal plasma cell proliferation
- Normal marrow with no evidence of clonal plasma cells or aneuploidy by flow-cytometry.
- Normal skeletal survey with proximal humeri and femora and a
- Normal magnetic resonance image of the axial skeleton (for Solitary Plasmacytoma of Bone); or a
- Normal regional computed tomographic scan (for Extramedullary Plasmacytoma).
- Absent or low serum or urinary concentration of monoclonal protein.
- No anemia, hypercalcemia, or renal insufficiency attributable A myeloma.
