Bone tumors More than 80% of bone tumors are either secondary or its multiple myaloma, and primary bone tumors accounts for less than 20% of all bone tumors.

Secondary bone deposits can reach the bone from any body malignancy but most commonly from: 1.Ca-lung 2.Ca-thyroid 3.Ca-breast 4.Ca-prostate 5.Ca-kidney 6.Colo-rectal carcinoma

The primary bone tumors are those arising from bony tissues itself and can be classified according to the cell of origin as below:

The commenst presenting symptoms are: Pain Swelling Local tenderness Accidentally diagnosed Pathological fracture

Signs that may suggest malignancy includes: Rapid growth Warmth Tenderness Ill-defined edges

Important investigations: Good x-ray CT-scan MRI Bone scan Good biopsy All must be done before planning for treatment or surgery

Types of biopsy: Fine needle aspirate cytology (FNAC): cells of the suspected tissue for CYTOLOGICAL exam looking for malignant cells. Wide-bore needle (CORE) biopsy; the wide needle used to recover a tissue piece for HISTOPATHOLOGICAL exam.

Incisional biopsy: surgical approach we aim at cutting small pieces of the tumor to be send for histopathology Excisional biopsy: for small accessible tumors where complete surgical excision is possible and the whole tumor mass send for histopathology

Types of surgical excision of a tumor: The final decision about type of tumor excision depends on its histopathological appearance whether benign or malignant and if its localized or metastasized.

Tumor excision can be: Intralesional excision (curettage): for benign lesions we open the capsule and curate the lesion. Marginal excision (local excision): also for benign lesions where the whole lesion with its capsule and few mm. Of the surrounding tissues is removed.

Wide local excision: for more aggressive tumors, its like marginal excision but here we remove few centimeters of the surrounding tissues EN-BLOCK with the tumor. Radical resection: it’s used for malignant tumors that are only locally invasive but not metastatized.it means amputation of the limb through the proximal joint.

Malignant tumors also need adjuvant treatment with radiotherapy and/or chemotherapy before and/or after amputation or excision if they are sensitive.

Benign bone tumors

Osteoid osteoma: Benign tumors consist of primitive osteoid tissue with neurovascular tuft (the nidus), its surrounded by a very thick sclerotic bone reaction. Round or oval in shape, less than 1cm. In size. Common in metaphysis or diaphysis, usually affects femur or tibia. Patient age usually below 30.

Pain is the main symptom, mainly at night and can be very severe sometimes relieved by aspirin. X-ray shows a small radiolucency (nidus=tumor) surrounded by thick sclerotic bone (bone reaction). Treatment by local excision of the nidus and surrounding bone.

Osteochondroma (cartilage capped exostosis): Commonest benign tumor of bone. Occurs during bone growth in adolescence.

Starts as cartilaginous overgrowth at the edge of the epiphysis and grow outside the bone on the same direction (towards diaphysis). its base later on ossify and show on x-ray as an exostosis (either narrow base- pedanculated or wide base-sessile).

Its growth continues with the bone and stops as the bone stops growing. any enlargement after that (specially if associated with pain) considered serious and regarded as malignant transformation until proved otherwise.

It can be single or multiple (multiple familial osteochondrom, congenital achlasis). Incidence of malignant transformation is about 1% in single and 6% in multiple osteeochondroma.

Pain or lump is the usual presentation. Sometimes accidentally discovered by x-ray or it may affect nearby joint or tendon function, sometimes it press on nearby important structures as vessel or nerve.

X-ray shows well-defined exostosis at the bone ends mainly around the knee. Any increase in size or pain after puberty must be concederd malignant transformation until proved otherwise. It can change to chodrosarcoma or osteosarcoma. Treatment is by local excision of the exostosis.

Chondroma Benign cartilage tumor. Single or multiple (Olliers disease). Occurs most usually in small bones of hands or feet also may occur in long bones.

It may grow inside the bone or on its outer surface. Patient may present with pain, swelling or pathological fracture. X-ray shows well-defined lucent area of bone contains specks of calcification.

Differential diagnosis includes bone cyst and chondrosarcoma. It usually affects patients above 30. Treated by excision or curettage +/- bone graft.

Non-ossifying fibroma (fibrous cortical defect)

Lucent fibrous tissue lesion (benign) inside bone cortex. Mostly accidentally discovered by x- ray. Seen in children and may disappear spontaneously with time during growth. X-ray shows eccentrically located lucent small defect in the bone

Seen mostly in the cortex of the metaphysis of long bones. Rarely if large may cause pathological fracture. Usually does not need treatment unless there is pathological fracture.

Fibrous dysplasia Developmental disorder whereby normal bone is replaced by fibrous tissue with flecks of osteoid. It may affect one bone (monostotic) or multiple bones (polystotic).

The lesion may be very large causes bone expansion and cortical thinning with progressive deformity and sometimes pathological fracture. Lesions occur in metaphysis & diaphysis, proximal femur is a common site it gives characteristic deformity called (shepherd’s-crock deformity(عصا الراعي.

X-ray shows lucent cystic lesion sometimes large and multilocular with bone expansion and cortical thinning it contains multiple calcific spots giving the ground-glass appearance, there is always possible deformity or pathological fracture. About 5-10% of polyostotic forms get malignant, while only rarely occurs in monostotic lesions.

Treatment depends on tumor size and possible deformity; –Small lesions may need no treatment, just follow up. –For larger lesions we do curettage and bone graft or cement. –Sometimes we need internal fixation. –Deformities may need corrective osteotomy. –Always there is tendency for recurrence.

Osteoblastoma (giant osteoid osteoma)

It’s benign and similar to osteoid osteoma but its larger and more cellular. It occurs in young adults, males more than females. Its commoner in the spine and flat bones& usually presents as pain or muscle spasm.

X-ray shows well-defined lytic lesion surrounded by thin zone of sclerosis, it may contain flecks of calcification. Treatment is by local excision and bone graft. Always there is tendency for recurrence and malignant changes are reported.

Bone cysts (tumor like conditions) Simple bone cyst Anurysmal bone cyst

Simple bone cyst (solitary or unicamerial bone cyst)

It’s not a tumor but it’s a tumor like condition. Common in upper humerous, femur and tibia. Seen in children up to the age of puberty. Presents as local pain or pathological fracture.

Occurs in the metaphysis and directed towards diaphysis. X-ray shows translucent cystic lesion in the metaphysis and shaft of bone with bone widening and cortical expansion and thinning with possible pathological fracture.

It may show bridges of calcification inside as a result of healing of micro fractures that commonly occurs, by this way it may gradually disappear and heals later in life; sometimes we use this criteria as a method of treatment by frequent aspiration and local steroid injections aiming at induction of such micro fractures that aids healing

Small cysts treated as above, for larger cysts we do curettage and bone graft.

Aneurysmal bone cyst Tumor-like cystic lesion forms of multiple cavities full with blood. Mostly seen in spine or eccentrically located in the metaphysis of long bones of young adults.

X-ray shows well-defined irregular eccentric lucent lesion in the metaphysis that does not reach the articular surface, it may show ballooning, cortical widening and thinning. Important differential diagnosis is giant cell tumor.

Treatment is by curettage and bone graft.

Giant cell tumor (osteoclastoma): (Sometimes-malignant tumor - Intermediate tumor)

Pathology: This tumor contains multinucleated giant cells and large number of stromal cells. Its soft friable tumor seen in the soft cancellous subarticular bone and never reach the articular surface. It’s a tumor of young adults occurs after bone maturity in the epiphysial region.

Its intermediate type of tumor (neither benign nor malignant) –About 1/3 of it remains benign, –1/3 is locally aggressive, –1/3have distant metastasis.

Clinical features: Patient aged There is pain or swelling near a joint, 10% presents with pathological fracture. O/E vague swelling at the bone end and signs of joint irritation.

X-ray: Rarefied area of the bone end reaching just below the articular surface. Eccentric lesion with bone expansion and ballooning with cortical thinning, sometimes pathological fracture. There may be calcific trabiculations inside the lesion giving it the commonly known saop-bubble appearance.

Treatment: For well-defined small and rather benign lesion, we can do curettage and burr-down with bone graft. Larger more aggressive lesions may need local excision and bone graft or prosthetic replacement.