Osteosarcoma
- most common bone malignancy in children overall
- more likely to occur during the second decade of life
Associated syndromes
- hereditary retinoblastoma
- associated with irradiation
- Li Fraumeni syndrome
- Rothmund Thomson syndrome
- short stature, skin telangiectasia, small hands and feet
- hypoplasticity and absence of thumbs
- also associated with
- craniospinal irradiation for brain tumors
- osteosarcoma
- paget disease
- enchondromatosis
- multiple hereditary exostoses
- fibrous dysplasia
Histopathology
- highly malignant pleomorphic spindle cell neoplasm
Types
pathological subtypes of conventional osteosarcoma
- fibroblastic
- chondroblastic
- telangiectatic
- osteoblastic
Other subtypes
- parosteal osteosarcoma
- low grade and well differentiated tumor
- found in the posterior aspect of femur
- surgical resection alone is often curative
- Periosteal osteosarcoma
- rare variant
- arises on the surface of bone
- higher rate of metastatic spread
- intermediate prognosis
Clinical manifestations
- pain
- limp
- swelling
- limitation of motion
- joint effusion
- tenderness
- deep bone pain with night time awakening
Diagnosis
- mixed blastic and lytic appearance on radiography
- sunburst pattern on Xray
- biopsy to confirm the histopathology
- MRI to be done before biopsy to evaluate for the proximity of nerves and blood vessels
Differential diagnosis
- histiocytosis
- ewing sarcoma
- lymphoma
- bone cyst
Treatment
- chemotherapy f/b surgery
- 60-70% disease free survival rate
- Chemotherapy regimen
- MAP - Methotrexate, Doxorubicin, Cisplatin
- additionally ifosfomide and etoposide can be used
- early prosthetic fitting and gait training followed by surgery and to avoid pathological fracture
Ewing Sarcoma
- second most common bone tumor in children
- most common bone tumor under the age of 10
- can arise from bone or from soft tissue
Clincial manifestation
- pain
- limp
- swelling
- limitation of motion
- joint effusion
- tenderness
- respiratory distress if chest wall tumor
- systemic manifestations
- fever
- weight loss
- elevated inflammatory markers
Diagnosis
- small round blue cell tumor
- immunohistochemical staining to differentiate from other tumors like lymphoma, rhabdomyosarcoma, neuroblastoma
- S100
- neuron specific enolase
- absent reactivity with muscle markers like
- MIC2 (CD99) staining positive
- FISH and PCR analysis for chimeric fusion protein EWS/FL11
- X-ray - onion skin appearance
- biopsy from at least two sites
- MRI to determine the extension of tumor and proximity to neurovascular structures
differential diagnosis
- primary lymphoma of bone
- Langerhans cell histiocytosis
- metastatic neuroblastoma
- rhabdomyosarcoma
Treatment
- multiagent chemotherapy + radiotherapy / surgery
- standard chemotherapy regimen
- cyclophosphamide
- etoposide
- ifosfomide
- radiosensitive tumor - but radiation is associated with the risk of induction of osteosarcoma
- surgical resection for local control