Dr varsha v s/ Dr jayakumar/ Dr Praveena Fourteen years old girl presented with c/o pain in the left leg while walking and high grade intermittent fever of past 3 weeks duration. As she is noticed to have a progressive swelling in the distal region of thigh associated with limping, weight loss and persistent fever she was referred to AIMS .
She was tired looking, pale and febrile with stable vitals. Systemic examination was within normal limits. Local examination done showed diffuse swelling in the left distal femur with warmth and tenderness on palpation.
Labs
CRP (345mg/L),
ESR (140mm/hr)
CBC normal counts
Low HB (7.3g/dl).
LDH, SE, ALP and LFT were normal
Xray knee showed mouth eaten pattern.
Differential considered were:
1. Osteomyelitis
2. TB
3. Osteosarcoma
4. Chondrosarcoma
5. ALL
6. Ewing sarcoma
Mantoux was non reactive.
IgM brucella was negative.
Peripheral smear done showed Iron deficiency anemia with no atypical or blast cells.
She was started on IV antibiotics with symptomatic management.
Blood culture done was sterile.
MRI of knee was done hyperintense lesion on T2 weighted image.
Biopsy done showed neoplasm composed of oval to spindle cells with moderate eosinophilic cytoplasm, hyperchromatic pleomorphic nuclei and conspicuous nucleoli. Bizarre cells are seen.
Osteoid matrix is seen.
Focal necrosis present.
Suggestive of spindle cell neoplasm favoring osteosarcoma.
She was planned for radical surgical treatment with chemotherapy.
Description:
Osteosarcoma is the most common primary pediatric bone malignancy, derived from primitive bone-forming (osteoid producing) mesenchymal cells.
Etiology: It can be divided to primary and secondary causes.
Primary is associated with genetic syndromes like
Hereditary Retinoblastoma
Li-Fraumeni Syndrome
Rothmund-Thompson Syndrome
Bloom Syndrome:
Werner Syndrome
Secondary osteosarcoma in patients with Paget disease, electrical burns, trauma, exposure to beryllium, exposure to alkylating agents, FBJ virus, osteochondromatosis, enchondromatosis, fibrous dysplasia, orthopedic prosthetics as well as bone infarction and infection
Epidemiology: Osteosarcoma has a bimodal age distribution. The initial peak is in the 10 to 14 year age group, corresponding to the pubertal growth spurt. Next observable peak is in adults older than 65. Osteosarcoma accounts for approximately 2.4% of pediatric cancers, making it the eighth most common childhood malignancy.
Clinical features: Symptoms of osteosarcoma may be present for a significant amount of time, sometimes weeks to months. Most commonly the presenting symptom is bone pain, particularly with activity and may or may not be a reported history of traumatic musculoskeletal injury. The pain may manifest as a limp. A swelling or lump may or may not be reported, depending on tumor size and location. Systemic symptoms like fever, night sweats are rare
Physical examination findings are typically focused around the location of the primary tumor and may include:
A palpable mass may be tender and warm with or without an overlying pulsation or bruit, though these signs are nonspecific
Joint involvement with decreased range of motion
Local or regional lymphadenopathy (unusual)
Respiratory findings with metastatic forms.
Investigation:
MRI is the gold standard for diagnostic imaging of osteosarcoma, radiographs are generally the first study obtained when a potential bone mass is identified on the physical exam. Xray features of osteosarcoma are medullary and cortical bone destruction, moth-eaten cortex, “Sunburst” configuration (due to aggressive periostitis), “Codman triangle” configuration (due to elevation of the periosteum away from the bone), ill-defined “fluffy” or “cloud-like” osseous lesion, soft-tissue mass, calcification of osteoid matrix produced the tumor.
Magnetic Resonance Imaging – MRI is an indispensable tool for defining the extent of a tumor inside and outside the bone. The entirety of the involved bone, as well as one joint above and one joint below the tumor, should be included in the study so that “skip” lesions are not missed.
Computed Tomography – the role of CT is primarily to assist with biopsy planning and disease staging.
Nuclear Imaging
Positron Emission Tomography – It is an essential tool that is useful for determining tumor extent of lesion and valuable for the detection of recurrence.
Radionuclide Bone Scan – Technetium 99 methylenediphosphonate (Tc99 MDP) bone scan is an effective and readily available imaging modality for detecting bony metastasis. It is a less expensive but less specific alternative to PET imaging
3. Biopsy .
Treatment: Primary modality of treatment is surgery followed chemotherapy based on the grade and extend of the tumor
Prognosis: The prognosis of osteosarcoma depends on
. Age: Middle-age patients (over 40 years old) have considerably worse survival rates than younger adults.
. Gender: Men reportedly demonstrate less response to chemotherapy, a higher propensity for recurrence, and a four-fold increase in morbidity.
· Biomarker Levels: Serum alkaline phosphatase, a biomarker associated with bone turnover, has been found in elevated levels in patients with osteosarcoma.
· Tumor Location: Patients with tumors located in the axial skeleton tend to fare worse compared to those diagnosed in the appendicular skeleton.
· Tumor Burden Larger/bulky tumors: carry worse prognoses than smaller lesions.
· Histology
Preoperative Chemotherapeutic Response: Necrosis of 90% or more of the tumor is associated with an excellent prognosis.
Pathological Fracture
Body Mass Index: High BMI has correlations with reduced overall survival