CLASSIFICATION OF BONE TUMOUR

A. Primary bone tumour
Origin
Benign
Malignant
        1.         
Cartilage
Osteochondroma
Chondroma
Chondreoblastoma
Chondromyxoid fibroma
Chondrosarcoma
        2.         
Bone
Osteoid osteoma
Osteoblastoma
* Osteochondroma (Commonest benign bone tumour)
* Osteosarcoma
(Commonest in adolescent)
        3.         
Bone marrow
Parosteal osteosarlomia
*Multiple Myeloma
(Commonest primary bone tumour in old age) Malignant hymphoma
        4.         
Fibrous tissue
Fibroma
Fibrosarcoma
        5.         
Vascular tissue
Aneurysmal bone cyst
Haimagioma Angioima
Malignant haemangioma
        6.         
Unknown origin
Giant cell tumour Fibros histocystoma
Malignant giant cell tumour
Ewing’s tumour adamantinoma
        7.         
Synovium
Synovioma
Synovial sarcoma

B. Secondary bone tumour
Metastatic tumour usually comes from
1.    Thyroid
2.    Breast
3.    Lungs
4.    Kidney
5.    Prostate

The Principle of management of bone tumour:
1.    Diagnosis of bone tumour either benign asymptomatic, benign symptomatic or malignant
2.    Treatment of the tumour
3.    Follow-up.
Diagnosis depends on:

1. History- Age incidence
Young adult (osteosarcoma)
Children (Ewing sarcoma)
Old age (Multiple myloma, secondary bone tumour)
Slowly growing growth- Benign
Rapidly growing growth- Malignant
History of Trauma (though trauma is not the cause) osteosarcoma

2. Clinical Feature
ü Size & shape regular- Benign; irregular- malignant
ü Margin- well defined- Benign; ill-defined- malignant
ü Over lying skin normal- Benign; fixed- malignant
ü Local temperature normal- Benign; Raised- malignant (Osteosarcoma)
ü Over lying structure free- Benign; fixed- malignant
ü Regional lymphode-not enlarged- Benign; May be enlarged- malignant
ü Usually no pain & tenderness-Benign; Pain & tenderness- malignant
ü No systemic features- Benign; Systemic features- malignant

Investigations:
I.       X-ray- small radiolucent nidus- osteoid osteoma
          well defined exostosis emerging from the meaphysis- osteochondroma
          Sun ray appearance + Codman’s triangle- Osteosarcoma
          Onion peel appearance- Ewing sarcoma
          Soap Bubble appearance- Giant cell tumour.


1.      CT  *     Show cortical crosion or fracture
                 *     Show intraosseons and extraosseons extension of tumour and the relation ship to surrounding structure.
                 *     Can detect pulmonary metastasis.
2.      MRI- The best method for evaluation soft tissue tumour
3.      Radionuclide scanning with 99m Tc- HDP
4.      Blood for i) Hb%- decreased  ii) ESR- raised
5.      Unire for Bence- jonces protein (i.e. multiple myeloma)
6.      Scrum alkaline phosphatase- increased
7.      Scrum acid phosphatase (in case of ca. prostate which cause secondary bone tumour)
8.      Biopsy       - FNAC
                             - Open biopsy- tissue is taken from boundary zone.
          Histopathological findings will confirm the diagnosis either benign or malignant. If malignant what type of the lesion is.

Treatment:
a)      Benign, asymptomatic tumour-treatment in not required; excision or curettage of the lesion can be done.
b)      Benign, symptomatic or enlarging tumour- They can generally be removed either by local (marginal) excisionor (in case of benign cysts) by curettage.
c)      Suspected malignant tumours- Treatment regions amputation, limb sparing operations and different types of adjuvant therapy.
Methods of Treatment:
1. Tumour excision-
a. Intra-capsular (intralesional) excision and curatase
b. Marginal excision
c. Wide excision
d. Radical resection
e. Limb sparing surgery
f. Amputation – for high grade tumour.
The preferred method for intra-capsular lesion is now wide excision together with pre and postoperative chemotherapy.

The resulting defect is dealt with in one of several ways:
1.    Vascularized or nonvascularized bone graft.
2.    Custom made implants
3.    Large allografts
4.    Custom made prosthesis
5.    Allograft prosthetic composites
6.    Extendible implants
7.    Grafting and arthrodesis
8.    Distraction osteosynthesis.

2. Multi-agent Chemotherapy:
This is now the preferred neoadjuvant and adjuvant treatment for malignant bone and soft tissue tumours. Modern chemotherapy regimes effectively reduces the size of the primary lesion. Prevent metastatic seeding and improve the chances of survival.
Drugs currently in use are methotrenate doxorubicin (adriamycin), cyclophosphamide, vincristine and cisplatin, Treatment is started 8-12 weeks preoperatively and the effect is assessed by examining the resected tumour. If there is little or no neurosis a different drug is selected for postoperative treatment. Maintenance chemotherapy is continued for another 6-12 months.
3. Radiotherapy:
High energy irradiation has long been used to destroy radio scrsitive tumour or as adjuvant therapy before operation. indications- for
1.    Highly sensitive tumours (such as Ewing sarcoma)
2.     Tumours in inaccessible sites
3.    Metastatic deposit and marrow cell tumour (i.e. myeloma & malignant lymphoma).
 OSTEOCHONDROMA
(Cartilage capped exostosis)
Mushroom like or cauliflower like tumour with degeneration and calcification in the canter of the cartilage cap. – osteochondroma.
Ø Origin- from epiphyscal cartilage.
Ø It is the commonest benign fumour of bone.
Ø The stalk and part of base of the tumour are of bone, but it is capped by cartilage.
Ø Tumour appears to migrate along the shaft towards its centre as the bone grows in length.
Ø Theory of histogenesis- ‘perichondrium’ perverted activity of periousteum which form cartilage & bone or accumulation of embryonic connective tissue at the points of tendinous insertion.

Clinical Features:
Ø Circumscribed hard swelling near a joint of a (knee, Ankle, hip, shoulder, elbow) teenager or young adult.
Ø Pain and tenderness suggests bursitis, malignant change, fracture of bony stalk, pressure on nerve etc.
Ø Any further enlargement often the end of the growth suggestive of malignant transformation.

Differential Diagnosis
1.    Hereditary multiple exostosis
2.    Ivory exostosis (compact osteoma)

Investigations
X-ray:
Ø Well defined exostosis emerging from the metaphysic.
Ø It looks smaller than it fells because the cartilage cap is not seen on X-ray.

Indication of Operation:
i.                   Joint interference- large osteochondroma obstruct joint movement
ii.                Painful bursitis
iii.             Of bony stalk due to traum
iv.             Malignent change
v.                Pressure on the neighboring vessels & nerves give rise to neurovascular complications.

Operation- Excision of the tumour along with its periosteal cover to prevent recurrence of the tumour.
Sudden increase in size & pain suggests malignancy.