MULTIPLE MYELOMA
MULTIPLE MYELOMA
- It is a malignant neoplasm derived from plasma cells.
Pathology:
- The neoplasm characteristically affects flat bones i.e.,
- the pelvis
- vertebrae
- skull, and
- ribs
It may occur as a:
- solitary lesion (plasmacytoma),
- multiple lesion (multiple myeloma),
- extra-medullary myelomatosis or diffuse myelomatosis.
- The lesions are mostly small and circumscribed.
- The bone is simply replaced by tumour tissue and there is no reactive new bone formation.
- Grossly, the tumour is soft, grey and friable.
- Microscopically, it consists of sheets of closely packed cells.
- Typically, the tumour cells have an eccentric nucleus with clumped chromatin.
Clinical features:
- The tumour affects adults above 40 years of age.
- Men are affected more often than women.
- Usual presentation is that of multiple site involvement.
- Common presenting complaint is increasingly severe pain in the lumbar and thoracic spine.
- Pathological fractures, especially of the vertebrae and ribs may result in acute symptoms.
- The patient is weak, and will have loss of weight.
- Neurological symptoms may result if the tumour presses on the spinal cord or the nerves in the spinal canal.
Investigations:
Radiological examination:
Characteristic radiological features are as follows:
- Multiple punched out lesions in the skull and other flat bones.
- Pathological wedge collapse of the vertebra, usually more than one, commonly in the thoracic spine.
- Diffuse, severe rarefaction of bones.
- Erosions of the borders of the ribs.
Other investigations:
Blood:
- Low haemoglobin,
- high ESR (usually very high),
- increased total protein,
- A/G ratio reversed,
- increased serum calcium,
- normal alkaline phosphatase.
- Urine: Bence Jones proteins are found in 30% of cases.
- Serum electrophoresis: Abnormal spike in the region of gamma globulin (myeloma spike) is present in 90% of cases.
- Sternal puncture: Myeloma cells may be seen.
- Bone biopsy from the iliac crest, or a CT guided needle biopsy from the vertebral lesion may show features suggestive of multiple myeloma.
- Bone scan: This may be required in cases presenting as solitary bone lesion, where lesions at other sites may be detected on a bone scan.
- Open biopsy: An open biopsy from the lesion may sometimes be required to confirm the diagnosis.
Treatment:
- It consists of control of the tumour by chemotherapy, and splintage to the diseased part by PoP, brace etc.
- Radiotherapy plays a useful role in cases with neurological compression, localised painful lesions, fractures and soft tissue masses.
Chemotherapy:
- Melphalan is the drug of choice.
- It is given in combination with Vincristine, Prednisolone, and sometimes Cyclophosphamide.
Exam Important
- Most common primary malignant bone tumor Multiple myeloma.
- Commonest site of lytic lesion in multiple myeloma is Vertebral column.
- Bone marrow plasmacytosis in multiple myeloma is characteristically more than 30%.
- Multiple myeloma will lead to increased viscosity of blood.
- Multiple punched out lesions on X-ray is seen in Multiple myeloma.
- Russell bodies are found in Multiple Myeloma.
- Increased ESR is seen in Multiple myeloma.
- Increased serum calcium is seen in Multiple myeloma.
- The immunoglobulin least commonly involved in Multiple Myeloma is IgD.
- The immunoglobulin most commonly involved in Multiple Myeloma is IgG.
- The most common translocation seen in patients with Multiple Myeloma is t(11;14).
- Excretory urography should be cautiously performed in Multiple myeloma.
- Drugs used in chemotherapy of multiple myeloma is Melphalan is the drug of choice
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