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Malignant Tumors of Bone (Overview & MM)

•Primary bone tumors are very rare.

•Osteosarcoma, Ewing’s sarcoma and Fibrosarcoma are primary malignant tumours of bone, they rarely present as a multifocal disease.

•Multiple malignant lesion usually indicate metastatic disease


•Bone tumours are defined as those conditions of the skeletal system that are neoplastic or could be mistaken for a neoplastic condition on the basis of radiological and/or pathological evidence.




Clinical presentation

1.Painless bony mass (usually benign)

2.Painful bony mass (usually malignant except Osteoid osteoma)

3.Soft tissue mass (feature of malignant and aggressive lesion)

4.Bone tumor as incidental finding

5.Pathological fracture


Approach to the Bone Tumour




Enneking Staging of Malignant bone tumours

•Grade (G) – Histological - G1 means low grade cancer ; G2 means high grade cancer; G0 means a benign tumour

•Stages 1 and 2 are divided into A and B:

•A means the cancer is still within the bone. Tumour is still completely inside the bone in which it started. It may press on the bone wall and cause swelling. - Intracompartmental

•B means the cancer has grown through the bone wall. – Extracompartmental.




Common Malignant tumors of bone

1.Multiple Myeloma

2.Osteosarcoma

3.Ewing’s Sarcoma

4.Chondrosarcoma

5.Malignant GCT

6.Fibrosarcoma

7.Histiocytic Lymphoma

8.Liposarcoma

9.Adamantinoma

10.Chrodoma


1. Multiple Myeloma

•Most common primary malignant bone tumor

•40% of primary bone tumor

•Male : Female = 2:1

•Peak at 7th decade

•Etiology :

•Not known

•Commonly seen in farmers, wood workers, leather workers, and those exposed to petroleum products

•Chromosomal abnormalities

•Pathogenesis :

•Plasma cell ( Terminally differentiated cell of B-cell lineage)

•Clonal neoplastic plasma cell transformation

•Over production of single antibody that appears in plasma (M-Protein)

•This clonal plasma cell activate osteoclasts by release of chemokines

•It is also associated with increased generation of osteoclast from monocyte precursors.



Skeletal Distribution :

Ribs, Skull, Pelvis, Long bones, Spine

In long bones : Metaphysis

In Spine : Body of vertebrae

Patho:

•Gross – Marrow is replaced by soft, gelatinous, radish grey or fleshy white tissue

•Histo – Atypical Plasma cells replacing normal fatty & hematopoietic marrow

•round plasma cells with an eccentric nucleus, prominent nucleolus, and cartwheel organization of chromatin

•characteristic clear area (Hoffa clear zone) next to the nucleus represents the prominent Golgi apparatus involved in immunoglobulin (protein) production

percentage of plasma cells on bone marrow aspirate

plasmacytoma (10-30% plasma cells) vs.

multiple myeloma (>30% plasma cells)

normal < 2%



Clinical Features :

•Bone pain – dull aching, intermittent, mostly localized to lower back, upper spine, pelvis, ribs, sternum

•Persistent pain indicates pathological fractures

•Bony lesion may expand and may be palpable ( especially on skull, clavicle, sternum)

•Susceptibility to infection

•Renal Failure ( d/t Hypercalcemia, BJ Proteins, Amyloidosis)

•Anemia

•d/t M protein interference :

•Clotting abnormalities (with clotting factor)

•Raynaud’s Phenomenon (cryoglibins)

•Hyper viscosity

•Constitutional symptoms


•Investigation :

CBC

•Unine - BJ Proteins

•Bone scan

•Bone marrow examination ( Sternum/ Iliac crest)

•Serum Protein Electrophoresis

•Cytogenetics

•Xrays

•CT Scan

•MRI


Xray in MM

•Generalized reduction in bone density

•Localized are of radiolucency

•Skull – Rain drop lesion, punched out, lytic lesion

•Marked bone expansion – “ballooned” appearance

•In spine – collapse of vertebral bodies, multiple level compression #


Treatment

•Chemotherapy

•Bone marrow transplant

•Corticosteroids

•MELPHALAN ( Alkylating Agent)

•Plasmapheresis

•ORTHO:

•Treatment of impending or actual pathological fracture of spine, acetabulum, proximal femur, proximal humerus

•ORIF with packing of cavities with bone cement

•Spine fractures needs immediate stabilization

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