ALL YOU NEED ABOUT BENIGN BONE TUMORS
Introduction
Benign tumors means it is not malignant not cancer not spread or invasion to other organs not causes serious problems like cancers rare to recur after complete excision sometimes the benign tumors acts as locally malignant tumors in some aggressive benign tumors and can recur after excision but they don not spread or metastasis to other structures
The benign bone tumors are more common than malignant bone tumors
The benign bone tumors are common to occurs in children and young age this related to bone growth at this age
Classifications of benign bone tumors
The benign or bone tumors in general are classified according to the site of origin or arising of the tumor from the mesenchymal bone tissue like from the bone ,cartilage, fat ,fibrous tissue, or endothelium
So the histogenic type of the tumour is depend on the tissue of origin
Specific tumors tend to occurs in particular bone or area of
bone as in the area of maximal growth or remodelling
Classified as follow
Bone forming tumors
Osteoid osteoma
Osteoma
Osteoblastoma
Cartilage forming tumour
Echondroma
Osteochondroma
Periosteal or paraosteal enchondroma
chondroblastoma
chondromyxoidfibroma
Fibrous tumor
Non ossifying fibroma
Fibrous dysplasia
Desmoplastic fibroma
Desmoid bone tumour
Vascular tuomour
Haemangioma
Miscellaneous or others
Brown tumour of hyperparathyroidism
Gaint cell tuomur
Bone cystic lesion
Unicameral(solitary) bone cyst or simple bone cyst
Common benign bone tumours
Bone forming tumours
Osteoid osteoma
• Age affects ages 5-30 years common in male than in female
Site: commonly In shaft of long bones (especially femoral neck) Also tibia, humerus and spine
Pathology: benign bone-forming tumour
• Presentation: pain that is worse at night. Pain relieved by aspirin ) caused by excess prostaglandin E2 production)
• Imaging: small less than 2 cm) radiolucent nidus, composed of osteoblastic tissue laying down woven bone, surrounded by reactive bone formation. Bone scan positive. CT scan can be diagnostic shows nidus
• Treatment: may heal or regress over a period 5-10 years. Resection or radiofrequency ablation (if non-operative treatment fails or is not acceptable
Osteoblastoma
Age affect primarily children and adult
Site any bone can be affected but the spinal vertebrae particularly its posterior elements is most often affected
It differentiated from osteoid osteoma which based on clinical and radiographic criteria as the lesion greater than 1 cm on diameter without or less reactive cortical sclerosis
Pathology vascular stroma woven bone formation gaint cells and osteoid may be present cellular lesion can easily be confused with osteosarcoma and careful evaluation is essential to avoid misdiagnosis
Presentation may present with pain
Imaging appear on plain X rays like the lesions are expansile and have a mixed lytic and blastic radio-graphic appearance
Treatment surgical marginal resection or curettage and bone grafting
Osteoma
This is small sessile benign bone tumour occurs most commonly in skull bone
may have no any symptoms also not required treatment
Consists of excrescence of surface bone
Similar lesions like as post-traumatic on the femur in the area of the adductor magnus muscle insertion(rider,s bone) or in relation to the medial collateral ligament of the knee Pellegrini Stieda lesion
Cartilage forming tumours
Osteochondroma or exostosis
Most common benign tumours of the bone
Age between 10-30 years peak incidence in 20 years
Site most common site at the growing ends or metaphysis of long bone including the distal femur proximal tibia and proximal humerus pelvis scapula and ribs
Pathology like bone outgrowth or exostosis from the surface of bone capped with a layer of cartilage may be single or multiple growth is slowly and the growth of the lesion usually ceases or stopped with skeletal maturity.
Malignant change to low grade chondrosarcoma can occur but rare especially with multiple lesions but it is very rare in solitary lesions
Presentation mostly discovered accidentally either following minor trauma routine examination if there is pain it may suggests possibility of malignant transformation also it may be a causes of impingement symptoms as nerve , tendon or muscle flick over the prominence of the osteochondroma and that need surgical excision
Multiple osteochondroma or multiple exostosis known as diaphyseal aclasis and may be hereditary or familial called multiple hereditary exostosis
Imaging on plain X rays they look like a mushroom with calcified stalk and radiolucent cap and typically grow away from joint it is size range from 2-15 cm
Treatment resection of the tumour if it is give rise to become symptomatic if asymptomatic lesions it is should be watched and investigated to exclude malignant transformation if they become painful
The lesion have a bony base and cartilaginous cap which may be broad (sessile osteochondroma ) or narrow called pedunculated osteochondroma
Chondroma or echondroma
Benign cartilage tumour arise from intramedullary cartilage compartment of bone
Age common in the first and fifth decades
Site within metastasis of long bone commonly hands and feet humerus femur and tibia
Pathology appear as well defined lesion of lobulated hayline cartilage with some area of ossification malignant transformation are rare to chondrosarcoma
Presentation commonly are discovered accidentally or incidentally finding pain may suggestive of malignant transformation may present with pathological bone fractures
Imaging on plain X rays appear as elongated oval lytic areas. well defined with narrow zone of transition . cortex preserved . area of calcification appear with age
Ollier,s disease this disease characterized by multiple enchondromatosis due to non hereditary developmental abnormality. may result in growth disturbance or deformity of affected bones high risk to change into malignant transformation to low grade chondrosarcoma
Maffucci,s syndrome this disease characterized by multiple enchrondromatosis in association with multiple haemangioma like Ollier,s disease it is non hereditary developmental abnormality with high risk of malignant transformation
Treatment if the tumour give rise symptoms it should be intralesional surgical resection or curettage and bone graft .asymptomatic tumour should be watched and investigated to exclude malignant transformation if they become painful it suspected malignancy and should be resected en bloc
Chondromyxoid fibroma
• Age common in children and adult Peak incidence in 40s.very rare tumour Typically in males it has local aggressive behavior with high rate of local recurrence and spread
• Site: epiphysis and metaphysis of long bones, commonly proximal tibia and femur
• Pathology: chondroid areas resemble hyaline cartilage. Tumour often lobulated, some times with small satellite tumours that are missed on plain films (but seen with MRI). Chondroid components and variable histological features mean this tumour may be mistaken for chondrosarcoma or chondroblastoma
• Presentation: vague aches and pains
• Imaging: round or oval, with rim of sclerotic reactive bone. May cause cortical expansiona and has three cellular component cellular fibroblastic area chondroid areas and myxoid areas with typical stellate tumour cell
• Treatment: surgical wide or marginal en bloc resection with bone grafting or bone cement to fill the residual defect also aggressive curettage with bone grafting also has been associated with good result
Chondroblastoma
Age and site common in the first and second decades of life 10-20 years this is one of the few epiphyseal tumours when the growth plate is still open
Pathology the lesion is composed of chondroblasts cartilage gaint cells and vascular stroma clear cell chondrosaecoma probably represented the malignant degenerative counterpart of chondroblastoma
Presentation the patient may present with pain joint effusion or contractures
Imaging plain X rays showing a lytic lesion with calcification in the epiphysis
Treatment surgical curettage and bone grafting
Parosteal chondroma or juxracortical chondroma
Age common in 20-30 years it is rare benign bone cartilage tumour
Arise from subperiosteum
Site common in humerus femur and small bones of the hand and feet
Pathology it showing halyine cartilage formed below the periosteum dosnot breach the cortex
More aggressive tumour can be locally recur after excision
Imaging plain X rays showing erosion and saucerisation of the cortex with buttresses of periosteal new bone formation
Treatment by surgical marginal or wide excision and bone grafting Fibrous forming tumours
Fibrous tumours
Fibroma
Also called Metaphyseal fibrous defect (fibrous cortical defect and non-ossifying fibroma
Fibroma Small intracortical fibrous lesions, referred to as fibrous cortical defects
Age common in children
Site common in metaphysis of long bone typically distal femur proximal tibia or distal tibia and tend to disappear spontaneously at skeletal maturity
Presentation are common incidental radiographic findings Larger variants. which can progressively enlarge into the medullary cavity and cause pathological fractures. are referred to as non-ossifying fibromas
Pathology The tumor consists of bland fibroblastic and histiocytic cells, with osteoclasts and cholesterol clefts from lipid-laden macropbages
• Imaging: eccentric, well-defined lucencies in cortex. Sclerotic rim, but no periosteal
A variant of this tumor that ossifies occurs in the mandible (ossifying fibroma). in larger or symptomatic lesions,
Treatment by surgical curettage and bone grafting is indicated, and recurrences after this treatment are uncommon.
Desmoid tumor
This is a rare aggressive fibrous tumor of bone that is analogous to its soft-tissue counterpart Aggresive fibromatosis,
. Treatment by surgical marginal to wide resection is indicated rather than curettage because of the tendency for local recurrence. With aggressive fibromatosis of soft tissues, local invasiveness causes frequent and progressively problematic recurrences
Good better results have been obtained by marginal to wide local resection in conjunction with moderate-dose (45 to 55 Gy) radiation therapy. Systemic therapy with methotrexate also has been reported to control or cause regression of aggressive fibromatosis
Fibrous dysplasia
• Age common present i ages less than 30 years
• Site: any bone can affected but commonly ribs, facial bones, proximal tibia, humerus and femur can affect one bone called monostatic) or many called polyostatic)
• Pathology: fibro-osseous abnormality of unknown aetiology. Fibrous tissue and disordered bone replace bone marrow, Malignant change very rare . Fibrous dysplasia is
, features of Albright syndrome
Presentation pathological fracture deformity or growth disturbance
• Imaging: diaphyseal lytic lesion with well-defined margins and ground glass appearance
• Treatment: self heals or disappear spontaneously or Internal fixation or curettage and bone grafting for symptomatic lesions
Vascular forming tumours
Haemangioma
• Age: common in young adults
• Site: common sites of skeletal involvement include the vertebral column, the ribs and long bones
• Pathology: typically cavernous haemangioma in the skeleton. Dilated blood-filled vessels lined by endothelium the lesion appear cystic and well marginated
• Presentation: usually incidental finding. May present with pain. Occasionally pathological vertebral wedge fractures
• Imaging: thickening of the vertebral trabeculae with (honey comb) appearance and showing increased local perfusion on bone scanning and angiography
• Treatment: surgery by wide local resection or curettage and radiotherapy in some cases also embolization of symptomatic lesions can be used
Cystic bone lesions
Unicameral(solitary) bone cyst or simple bone cyst
• Age: common occurs children and adult in 1st and 2nd decades
• Aetiology: unknown cause. Possibly due to high intra-osseous pressure and focal bone necrosis
• Site: metaphysis. 90% in proximal humerus and proximal femur also radius calcaneus and tibia can be affected
• Pathology: thin walled cavity with cuboidal cell lining. Filled with straw-coloured or blood-stained fluid with high levels of bone resorptive cytokines the cyst tend to disappear at skeletal maturity in older children and young adult the lesion become latent stage I and not progress stage II active stage recurrence after surgical treatment
• Presentation: often asymptomatic. and usually painless May present after pathological fracture
• Imaging: plain X rays showing multi-loculated appearance (only one cavity, but ridges give loculated appearance). Thinning, but no expansion of cortex. May see fragment of cortex if fractures (fallen-crescent sign
Treatment: may resolve spontaneously. Tend to heal following fracture. If symptomatic or impending fracture consider aspiration or curettage and bone grafting
Injection of steroid drugs like methylprednisolone may causes partial or complete healing with good results
Aneurysmal bone cyst ABC
• Age: most common occur in children and young adult aged less 20 years
• Site: metaphysis of long bones and vertebrae. Typically proximal humerus, distal femur and proximal tibia
• Pathology:cystic cavity with multiple blood-filled spaces. Surrounded by thin layer of bone and periosteum. Association with other bone tumours. Some ossify spontaneously but most are progressive and destructive
• Presentation: pain and swelling
• Imaging: plain X rays showing expanding radiolucent cyst
• Treatment:preoperative embolization of large lesions is helpful to decrease the risk of haemorrhage curettage or better local resection and bone grafting, to prevent recurrence with local adjuvant therapy (eg phenol) or resection for higher grades
Embolization has been used in unresectable spinal or pelvic lesions
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