Orthopaedic Surgery - Tumors

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Basics

A neoplasm is an abnormal proliferation of cells characterized by:

Unregulated growth.

Neoplasms are broadly classified as:

Benign

or

Malignant.

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Benign Neoplasms

A benign neoplasm generally demonstrates:

Localized growth

without the ability to:

Metastasize to distant organs.

Although benign tumors do not metastasize, some may still become locally aggressive and can:

Compress

Replace

or

Damage adjacent tissues.

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Malignant Neoplasms

Malignant tumors have the capacity for:

Local invasion

and

Metastatic spread.

Tumor cells may enter:

Blood vessels

or

Lymphatic channels

and disseminate to distant:

Organs and tissues.

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Important Pathologic Distinction

The distinction between benign and malignant neoplasms is based on features such as:

Local invasiveness

Cellular atypia

Growth behavior

and

Metastatic potential.

The concept of crossing a basement membrane is particularly relevant to:

Epithelial malignancies

but is not a universal defining feature of all musculoskeletal tumors.

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Epidemiology

Both benign and malignant neoplasms arise through accumulation of:

Genetic and epigenetic abnormalities.

Tumor development usually requires multiple alterations affecting cellular:

Growth

Survival

and

Genome regulation.

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Genetic Instability

Neoplastic cells frequently demonstrate increasing:

Genetic instability

as the tumor evolves.

Historically, approximately:

4–6 important genetic alterations

have been described as sufficient to contribute to malignant transformation in some tumor models.

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Hallmarks of Malignancy

Classic biologic characteristics of cancer include:

Sustained proliferative signaling

Resistance to growth-suppressive signals

Avoidance of programmed cell death

Replicative immortality

Angiogenesis

and

Tissue invasion with metastatic potential.

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Incidence

Primary malignant tumors of bone are:

Rare.

Historical estimates in the United States have been approximately:

3,000 new malignant primary bone tumors per year.

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Soft-Tissue Sarcoma

Primary malignant soft-tissue tumors are more common than primary bone malignancies but remain:

Uncommon.

Historical estimates have been approximately:

9,000 new cases annually in the United States.

Incidence estimates vary by:

Year

Tumor definition

and

Data source.

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Risk Factors

For most neoplasms, particularly benign musculoskeletal tumors, the exact cause is:

Unknown.

Some malignant tumors have identifiable:

Genetic

Environmental

or

Infectious risk factors.

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Genetic Risk Factors

Important tumor suppressor abnormalities include:

TP53

and

RB1.

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TP53

Germline TP53 mutation is associated with:

Li-Fraumeni syndrome

and an increased risk of multiple malignancies, including some:

Sarcomas.

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RB1

Germline mutation of:

RB1

causes hereditary:

Retinoblastoma

and also increases the later risk of certain:

Bone and soft-tissue sarcomas.

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Environmental Risk Factors

Environmental exposures associated with malignancy include:

Tobacco use

Excessive alcohol consumption

Obesity

and

Ultraviolet radiation.

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Tobacco

Tobacco exposure is strongly associated with malignancies such as:

Lung cancer.

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Alcohol

Heavy alcohol consumption increases the risk of several cancers, including:

Esophageal malignancy.

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Obesity

Obesity is associated with increased risk of several malignancies, including:

Colorectal cancer.

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Ultraviolet Exposure

Excessive ultraviolet light exposure increases the risk of:

Skin malignancy.

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Infectious Risk Factors

Some malignancies are associated with specific:

Infectious agents.

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Human Papillomavirus

High-risk HPV strains are strongly associated with:

Cervical cancer

and several other:

Anogenital and oropharyngeal malignancies.

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Epstein-Barr Virus

EBV is associated with several malignancies, including certain:

B-cell lymphomas.

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Hepatitis Viruses

Chronic:

Hepatitis B

and

Hepatitis C

infection increase the risk of:

Hepatocellular carcinoma.

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Helicobacter pylori

Chronic infection with:

Helicobacter pylori

is associated with:

Gastric adenocarcinoma

and

Gastric MALT lymphoma.

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Pathophysiology

Both benign and malignant tumors demonstrate:

Abnormal cellular proliferation.

Their biologic behavior differs primarily in:

Local invasiveness

Growth rate

Histologic aggressiveness

and

Ability to metastasize.

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Benign Tumor Behavior

Benign tumors generally remain:

Localized.

However, some may become locally destructive because of:

Expansion

or

Pressure on surrounding structures.

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Malignant Tumor Behavior

Malignant tumors can invade surrounding tissues and may disseminate through:

Bloodstream

Lymphatics

or other anatomic pathways.

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Hematogenous Metastasis

Many primary bone sarcomas spread predominantly through the:

Bloodstream.

A common metastatic destination is the:

Lung.

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Associated Conditions

Certain inherited disorders predispose patients to specific tumor types.

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Gardner Syndrome

Gardner syndrome is associated with:

Familial adenomatous polyposis

and may include:

Osteomas

Desmoid tumors

and other:

Soft-tissue lesions.

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Neurofibromatosis

Neurofibromatosis may be associated with:

Neurofibromas

and an increased risk of:

Malignant peripheral nerve sheath tumors.

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Diagnosis

Evaluation begins with:

History

Physical examination

and appropriate:

Imaging.

Definitive diagnosis often requires:

Tissue biopsy.

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Signs and Symptoms

Possible systemic or local symptoms include:

Fever

Night sweats

Unintentional weight loss

Bone pain

Soft-tissue mass

Abdominal pain

Visual symptoms

Abnormal bleeding

and

Persistent cough.

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Bone Pain

Persistent unexplained bone pain, particularly when:

Progressive

Nocturnal

or unrelated to activity, warrants further:

Evaluation.

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Soft-Tissue Mass

A newly enlarging or persistent soft-tissue mass should be assessed carefully, particularly when it is:

Deep

Firm

Painful

or

Progressively enlarging.

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Physical Examination

Examination should be directed by the patient’s:

Symptoms

and

Tumor risk profile.

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General Examination

The examination may include assessment of:

Skin

Lymph nodes

and other organ systems where clinically appropriate.

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Musculoskeletal Examination

For suspected orthopaedic tumors, assess:

Mass size

Location

Depth

Mobility

Tenderness

Neurovascular status

and relationship to surrounding:

Bone and soft tissue.

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Laboratory Tests

There is no single blood test that reliably diagnoses most:

Bone or soft-tissue tumors.

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Selected Laboratory Studies

Depending on the suspected diagnosis, testing may include:

CBC

ESR

CRP

Serum calcium

Alkaline phosphatase

SPEP/UPEP

or other disease-specific:

Studies.

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Imaging

Imaging plays a central role in:

Detection

Characterization

Local staging

and

Metastatic assessment.

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Plain Radiographs

Plain radiographs should be obtained for areas of:

Persistent focal bone pain

or suspected:

Bone lesions.

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Radiographic Assessment

Important features include:

Lesion location

Margins

Pattern of bone destruction

Matrix mineralization

Periosteal reaction

and presence of:

Soft-tissue extension.

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Chest Imaging

Chest radiography or, more commonly for sarcoma staging:

CT of the chest

may be used to assess for pulmonary:

Metastases.

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CT

CT is useful for:

Cortical detail

Mineralized matrix

and staging of:

Chest, abdomen, and pelvis

when clinically indicated.

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MRI

MRI with and without contrast is the preferred local imaging study for many:

Soft-tissue masses

and complex:

Bone tumors.

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Role of MRI

MRI helps define:

Tumor extent

Relationship to neurovascular structures

Marrow involvement

and

Soft-tissue extension.

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Staging

Staging systems vary according to:

Tumor type.

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Staging Methods

Staging may incorporate:

Clinical findings

Imaging

and

Histopathology.

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Primary Tumor Assessment

Local tumor extent is commonly evaluated using:

MRI

or

CT.

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Metastatic Evaluation

Metastatic staging may include:

CT chest

Bone scintigraphy

PET/CT

or other imaging tailored to the:

Specific malignancy.

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Biopsy

When malignancy is suspected, biopsy should generally be performed:

After complete imaging

and ideally planned by the team that will perform definitive:

Tumor resection.

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Biopsy Principles

The biopsy tract should be positioned so that it can be:

Removed during definitive surgery.

Poorly planned biopsy can contaminate:

Uninvolved tissue planes

and complicate future:

Limb-sparing surgery.

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Differential Diagnosis

A bone or soft-tissue lesion may represent:

Benign neoplasm

Primary malignancy

Metastatic disease

Hematologic malignancy

Infection

or a:

Tumor-like condition.

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Benign Bone Lesions

Common benign or incidental bone lesions include:

Bone islands

Enchondromas

and

Bone infarcts.

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Treatment

The primary goals of cancer treatment are:

Local tumor control

and prevention or treatment of:

Metastatic disease.

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Multidisciplinary Care

Treatment often requires collaboration among:

Orthopaedic oncology

Medical oncology

Radiation oncology

Pathology

and

Radiology.

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Chemotherapy

Chemotherapy is important for selected malignancies such as:

Osteosarcoma

Ewing sarcoma

and many:

Hematologic cancers.

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Immunotherapy

Immunotherapy may be effective for selected tumors with appropriate:

Biologic or molecular targets.

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Radiation Therapy

Radiation may be used for:

Definitive local control

Adjuvant treatment

or

Palliation

depending on tumor type.

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Surgical Resection

Surgery remains central to treatment of many:

Primary bone and soft-tissue sarcomas.

The goal is usually complete removal with an appropriate:

Oncologic margin.

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Limb Salvage

When possible, malignant musculoskeletal tumors may be treated with:

Limb-sparing resection

followed by reconstruction.

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Amputation

Amputation remains appropriate in selected cases involving:

Extensive neurovascular invasion

Uncontrollable infection

or when limb salvage would not provide acceptable:

Function or oncologic control.

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Follow-Up

Patients require ongoing:

Clinical surveillance

and

Restaging imaging.

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Purpose of Surveillance

Follow-up aims to detect:

Local recurrence

and

Metastatic disease

at an early stage.

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Duration of Follow-Up

The frequency and duration of surveillance depend on:

Tumor type

Grade

Stage

and time since:

Treatment.

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Prognosis

Prognosis varies widely according to:

Histologic diagnosis

Tumor grade

Tumor size

Location

Resectability

and presence or absence of:

Metastatic disease.

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Patient Monitoring

Surveillance may include:

Physical examination

Local imaging

and imaging of common metastatic sites such as the:

Lungs.

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Patient Teaching

Patients should be educated to recognize possible signs of:

Local recurrence.

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Warning Symptoms

They should seek medical evaluation for:

New pain

New swelling

or development of a:

New mass

near the site of a previous tumor.

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Frequently Asked Questions

Are all bone lesions cancerous?

No. Most incidentally discovered bone lesions are:

Benign.

Examples include:

Bone islands

Enchondromas

and

Bone infarcts.

Their appearance and behavior are assessed primarily with:

Imaging characteristics.

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Can an orthopaedic oncologist determine whether a bone lesion is aggressive?

Often, yes. Features such as:

Margins

Bone destruction

Periosteal reaction

Cortical involvement

and

Soft-tissue extension

help determine whether a lesion appears:

Nonaggressive or aggressive.

Musculoskeletal radiologists can provide important additional:

Imaging interpretation.

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Is a bone scan always needed to determine whether a lesion is active?

No. Bone scintigraphy may be useful in selected situations, but activity is often assessed with:

Plain radiographs

MRI

CT

or other imaging depending on the:

Lesion.

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Can staging studies determine whether a malignant tumor has metastasized?

Staging studies are useful for identifying:

Macroscopic metastatic disease.

However, they cannot reliably detect:

Microscopic metastases.

Therefore, apparently localized disease on imaging does not prove that no microscopic tumor cells are:

Present elsewhere.

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Clinical Summary

Definition: A neoplasm is an abnormal proliferation of cells classified as benign or malignant according to its biologic behavior.

Benign tumors: Usually remain localized and do not metastasize, although some may be locally aggressive.

Malignant tumors: Invade surrounding tissues and may metastasize, often hematogenously in primary bone sarcomas.

Key warning features: Progressive bone pain, enlarging soft-tissue mass, constitutional symptoms, or an aggressive lesion on imaging.

Initial imaging: Plain radiographs for bone lesions and MRI with contrast for suspicious soft-tissue masses or local tumor staging.

Staging: Often includes local MRI or CT plus metastatic evaluation such as CT chest, PET/CT, or bone scintigraphy, depending on tumor type.

Biopsy principle: Biopsy should be planned after imaging and ideally by the team performing definitive tumor surgery.

Treatment: May include surgical resection, chemotherapy, radiation therapy, and immunotherapy, depending on the specific malignancy.

Follow-up: Requires surveillance for both local recurrence and metastatic disease.

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Key Principle

Musculoskeletal tumors range from common benign incidental lesions to rare but potentially lethal:

Primary bone and soft-tissue malignancies.

The most important early steps are:

Recognizing aggressive clinical or imaging features

Obtaining appropriate local imaging

and

Planning biopsy correctly before definitive treatment.

Most bone lesions are:

Benign, but suspected malignant tumors should be evaluated using a coordinated:

Multidisciplinary oncologic approach.

For malignant disease, treatment aims to achieve:

Local control

while preventing or treating:

Metastatic spread.