Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

Featured on Channel NewsAsia

Tumor

Basics

Description
  • Bone tumors can be divided into 4 categories:
    • Benign primary:
      • Common, usually in young patients
      • Most common forms: Osteochondromas, osteoid osteoma, and giant cell tumors
    • Malignant primary:
      • Rare, but more common in the 2nd and 3rd decades than at other ages
      • Responsible for <1% of deaths from cancer
      • Most common forms in patients 10-25 years old: Osteosarcoma and Ewing tumor
      • Most common forms in older patients: Chondrosarcoma and MFH
    • Metastatic:
      • The most common destructive tumors encountered in adults, usually in the 4th-8th decades
    • Lesions that simulate bone tumors:
      • Uncommon
      • In children: Infection, EOG, and stress fracture
      • In adults: Paget disease, hyperparathyroidism
      • Myeloma and lymphoma are common malignancies that occur in bone but are not of mesenchymal origin.
      • Soft-tissue tumors are benign or malignant and rarely metastasize to bone.
      • Although primary soft-tissue sarcomas are twice as common as all bone sarcomas combined, together they constitute <1% of all cancer deaths.
Epidemiology
Incidence
  • 3,000 bone sarcomas per year
  • 9,000 soft-tissue sarcomas per year
Risk Factors
Genetics
Ewing tumor is associated with translocation t(11;22)(q24;q12).
Associated Conditions
  • Conditions in which bone malignancies may develop:
    • Multiple hereditary exostoses
    • Solitary osteochondroma
    • Paget disease
    • Bone infarcts
Diagnosis
Signs and Symptoms
  • Pain:
    • Most patients with bone tumors present with musculoskeletal pain.
    • Typically, it is described as dull, deep, aching pain.
    • It often becomes constant and occurs at night.
  • Swelling
  • Loss of function at the involved site
  • Weight loss occurs with metastatic disease.
  • Acute symptoms of a pathologic fracture: In up to 5-10% of patients, pathologic fracture is the 1st evidence of the underlying disease.
  • Soft-tissue tumors:
    • More common than bone tumors
    • Patients may present with a small lump or a large mass.
    • The lesion often enlarges and may be painful or painless.
Physical Exam
  • Perform a complete musculoskeletal examination.
  • Inspect the affected site for soft-tissue masses, overlying skin changes, and adenopathy.
  • When metastatic disease is suspected, examine the thyroid gland, lungs, abdomen, prostate, and breasts.
Tests
Lab
  • These tests often are nonspecific, but routine studies should be obtained in any patient with a suspected tumor.
    • Patients 5-30 years old:
      • Complete blood count with differential
      • Peripheral blood smear
      • ESR
    • Patients >40 years old:
      • Complete blood count with differential
      • Peripheral blood smear
      • ESR
      • Serum calcium and phosphate
      • Serum or urine protein electrophoresis
      • Urinalysis
    • Biopsy:
      • Key to diagnosis
      • It is beneficial to the pathologist and surgeon to have a narrow working diagnosis at the time of the biopsy.
      • The biopsy should be done at the center where the treatment is to be given.
Imaging
  • Plain radiographs in 2 planes of the affected area are the 1st imaging examinations indicated.
    • Determine the matrix characteristics (bone, cartilage, or amorphous).
    • Determine the anatomic location within the bone (epiphyseal, metaphyseal, or diaphyseal).
    • Determine the number of lesions.
    • Determine the effect of the lesion on bone.
    • Determine the bone’s response to the lesion.
  • A chest view also should be obtained when malignancy is suspected.
  • Technetium bone scanning is indicated for clinical suspicion of malignancy in the presence of normal plain radiographs.
  • A skeletal survey is indicated for patients with myeloma for whom the bone scan may be negative.
    • AP and lateral views of the cervical spine, thoracic spine, and lumbosacral spine
    • AP views of the pelvis, femora, tibiae, fibulae, humeri, radii, and ulnae
  • MRI:
    • Preferred modality for screening the spine for occult metastases, myeloma, or lymphoma
    • For soft-tissue tumors, best imaging modality for defining anatomy and precisely depicting lesion
Differential Diagnosis
  • Based on clinical and radiographic findings
  • Patient age:
    • Young patients (10-25 years old)
      • Benign: Infection, EOG, enchondromatosis
      • Malignant: Osteosarcoma, Ewing sarcoma, leukemia, or lymphoma
    • Older adults (>25 years old):
      • Benign: Paget disease, hyperparathyroidism, enchondroma
      • Malignant: Metastatic bone disease, multiple myeloma, lymphoma, primary mesenchymal tumors, chondrosarcoma, MFH
  • Matrix characteristics:
    • Cartilage calcification may appear stippled with apparent rings, whereas bone may be cloudlike and may show trabeculae.
    • Cartilage-forming tumors include enchondroma, osteochondroma, chondromyxoid fibroma, chondroblastoma, and chondrosarcoma.
    • Bone-forming tumors include osteoid osteoma, osteoblastoma, and osteosarcoma.

    P.475
  • Number of bone lesions:
    • Indicates whether the process is monostotic or polyostotic
    • Multiple destructive lesions in patients >40 years old are most likely metastatic bone disease, multiple myeloma, or lymphoma.
    • In younger adults, multiple lytic lesions are most likely a vascular tumor, multiple enchondromatosis, or LCH (EOG).
    • In children <5 years old, multiple destructive lesions may represent metastatic neuroblastoma, Wilms tumor, or LCH.
  • Anatomic location:
    • Chondroblastoma most commonly occurs in the epiphysis of long bones.
    • Ewing tumor often involves the diaphysis.
    • Osteosarcoma most commonly is seen at the metaphysis of the distal femur and the proximal tibia.
  • Effect of the lesion on bone:
    • A lytic (radiolucent) lesion is less dense than surrounding bone.
    • An osteoblastic (radiopaque) lesion is more dense than surrounding bone.
  • High-grade malignant lesions:
    • Usually spread rapidly through the medullary canal
    • Cortical bone is destroyed early, and the tumor may spread to the soft tissues.
    • Often, the host bone has little ability to contain the process, and it may appear diffuse or permeative.
  • Low-grade malignant lesions:
    • Tend to spread slowly
    • Host bone often can contain the lesion with a thickened cortex or rim of periosteal bone, to give a well-circumscribed appearance.
    • Reactive new bone formation with periosteal elevation into an onion skin pattern may suggest Ewing sarcoma, osteosarcoma, or osteomyelitis.
Treatment
General Measures
  • Immediately after diagnosis:
    • Referral should be made to a musculoskeletal oncologist for proper staging, biopsy, and treatment as appropriate.
    • An improperly placed biopsy needle or biopsy incision can have a severely adverse affect on the patient’s clinical course, and thus patients should be referred only to orthopaedists who specialize in tumor management.
    • A team approach to treatment includes an orthopaedic tumor surgeon, pathologist, medical or pediatric oncologist, radiation oncologist, social worker, and physical therapist.
    • For diagnosis of a malignant primary sarcoma, a pulmonary CT scan is performed to evaluate for metastases, which helps complete the staging and determine the treatment plan and prognosis.
  • Treatment:
    • The diagnosis, histologic grade, and the size of the tumor:
      • Essential for determining treatment and prognosis
      • Helpful for determining whether adjunctive treatment (chemotherapy or radiation therapy) is to be given before surgical treatment
    • Options:
      • Neoadjuvant (preoperative) chemotherapy has a substantial impact on the efficacy of limb salvage and disease-free survival for patients with osteosarcoma and Ewing tumor.
      • External-beam irradiation is used for local control (Ewing tumor, lymphoma, myeloma, and metastatic bone disease) and adjunctively (in combination with surgery, for the treatment of soft-tissue sarcomas); the ionizing irradiation can be delivered preoperatively, perioperatively with brachytherapy after loading tubes, or postoperatively.
Special Therapy
Radiotherapy
  • Used to destroy any cells that may have escaped surgical treatment
  • In some cases, used to shrink the tumor preoperatively in locations where it is difficult to determine tumor margins clearly
Follow-up
Prognosis
  • Depends on the specific lesions (in general, 5-year survival:
    • Low grade: >90%
    • High grade: 40-60%
Complications
  • Cauda equina syndrome:
    • True orthopaedic emergency that can occur with metastatic tumors
    • Massive, central lumbar disc herniation with saddle anesthesia
    • Bowel and bladder paralysis (unable to void, rectal incontinence)
    • Emergency MRI and discectomy or decompression needed
Patient Monitoring
  • The pulmonary system is monitored closely after treatment of primary sarcomas:
    • First 2 years: Every 3-4 months
    • From 2-5 years: Every 4-6 months
    • From 5-10 years: Every 6 months
Miscellaneous
Codes
ICD9-CM
238.0 neoplasm of uncertain behavior of other and unspecified sites and tissues (bone and articular cartilage)
Patient Teaching
Patients are apprised of the staging strategy and the treatment based on the diagnosis.
FAQ
Q: What are the most important presenting symptoms of a malignant bone tumor?
A: Bone pain at rest and at night are the most common symptoms. The pain often progresses from intermittent to constant and is not relieved by NSAIDs or weak narcotics.
Q: What is the prognosis for the common malignant bone tumors in young patients?
A: Multiagent chemotherapy in both osteosarcoma and Ewing tumor has improved the 5-year disease-free survival to 60-70%.
Q: Is a biopsy necessary to confirm the diagnosis of a malignant bone tumor?
A: In general, a needle or open biopsy is necessary to establish the diagnosis and to plan treatment.

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