30 - Benign and Malignant MSK Tumors Flashcards
What’s on your differential diagnosis if a child has a malignant bone tumor?
Osteosarcoma
Ewing’s sarcoma
Lymphoma
What’s on your differential diagnosis if an adult has a benign bone tumor?
Giant cell tumor or fibrous dysplasia
What are signs of rapid bone tumor growth?
Permeation of the cortex, large soft tissue mass, non-sclerotic rim (doesn’t have time to build a wall around it)
What are the ways in which the bone can produce a matrix? What type of tumor doesn’t make a matrix (lacks mineral)?
- Osteoid
- Chondroid
- Dystrophic calcification
Lack of mineral: mainly a cellular tumor that lacks matrix, fibrous tumor, cyst production
How would you work up a bone lesion with imaging?
- Xray of entire affected bone
- MRI
- Whole body scan (or skeletal survey)
- CT C/A/P or PET/CT
How do you work up a bone lesion with lab work?
Multiple myeloma: SPEP/UPEP/Serum free light chains
In prostate cancer: PSA
Inflammatory markers (crp, esr, cbc)
What are some common benign tumors?
- Nonossifying fibromas/fibrous cortical defect
- Osteochondroma/exostosis
- Osteoid osteoma
What is the most common bone lesion in children that’s benign?
Nonossifying fibroma - usually asymptomatic and normally heal on their own.
What is an osteochondroma and where does it occur? Are they benign or malignant? What can cause them?
Common bone lesions - metaphyseal (growth plate) location in long bones. Grows away from epiphysis; malignant transformation rare (<1%).
Multiple hereditary exostoses: aut dominant, EXT-1 mutation with 20-40% malignant transformation to low grade chondrosarcoma.
What are symptoms of an osteoid osteoma? Where are they usually located?
Gradually increasing pain, nocturnal exacerbation, relief with oral ASA or NSAIDs. COX and PG abundant.
Diaphysis of long bones, 50% femur.
How should you image an osteoid osteoma?
Xrays
CT scans
MRI may be helpful but there’s little surrounding ST reaction
Bone scans: nidus well localized..doesn’t help with differential
What are the classic treatment methods for an osteoid osteoma?
En bloc resection: pre-label with tetracyclin and observe under woods lamp
Local curettage: Local curettage and bone grafting
Observation: and symptomatic treatment. Looks for non-accessable lesions. Treat with ASA, naproxen, ibuprofen.
What is the gross appearance of osteoid ostemoa? What is the appearance on histology?
Gross: Less than 2cm, reddish color, soft tissue gritty due to osteoid. Surrounding reactive bone.
Histology: nidus surrounded by dense cortical reactive bone. Active nbuclei with benign characteristics. Osteoblastic rimming, vascularity.
What is the most common primary malignant bone tumor in adults? Describe this.
Multiple myeloma; this is actually a “bone marrow” tumor that consists of malignant plasma cells.
Cells make abnormal immunoglobulins that don’t fight infection well (IgG, IgA, IgM).
Light chains may be made as well.
What does multiple myeloma look like on radiographs?
Multiple bones, indistinct, moth-eaten lesions.
Not any reaction around the lesions; pathologic fractures occur in long bones and vertebrae.
Describe the other illnesses that are often found with multiple myeloma?
Systemic illness, anemia (BM overtaken by plasma cells), may be thrombocytopenic (bleed easily), renal compromise/failure.
Don’t fight infection well due to having the wrong immunoglobulins. Prone to infections and complications post-op.
How do you diagnose and treat multiple myeloma?
Biopsy a lesion and perform BM aspiration to diagnose. Subtypes by chromosomal analysis.
Treatment: chemo, stem cell transplant, treat pathologic fractures.
What is the most common neoplasm in bone? How does it cause death?
Metastatic carcinoma.
Primary tumor seldom the cause of death, disability and death is caused by invasion of vital organs and multi-system failure.
What are common cancers causing bone metastases?
BLTKP - breast, lung, thyroid, prostate, kidney.
80% of metastases originate in the ling, breast, and prostate.
The majority of destructive bone lesions in adults are caused by what?
Metastatic carcinoma: lesins may be lytic or blastic
What are the two types of pts presenting with skeletal metastases?
Pt with known primary tumor
Pt presenting with a destructuve bone lesion and unknown primary tumor
85% of primary tumors were diagnosed with what?
CT, total body bone scanm PET scans, or needle biopsy.
What are treatments for metastatic carcinoma?
- Treat impending fractures. with minimally invasive techniquies
- Radiation therapy to treat tumor and dminish pain
- Bisphosphate therapy (anto-osteoclast)
- Chemo
- Embolic treatment of vascular lesions
What is the most common primary malignant bone forming tumor of childhood and youth?
Osteosarcoma - peak incidence in teens and early 20s.
Composed of malig osteoblasts forming osteoid at the metaphyseal region of bones.
What are some radiographic features of an osteosarcoma?
- Metaphyseal tumor
- Bone destruction cortical and trabecular
- Periosteal and endosteal new bone formation
- Codman’s triangle
- Soft tissue extension - mineralization
Why might you look at a bone scan to see an osteosarcoma? How does this test work?
Determine’s presence of multi-focal disease
- Marked uptake of Tc99 MDP - uptake indicative of osteoblastic activity.
- Sensitive but not specific (could be from infections, fractures, or benign tumors too)
Why might an MRI be useful to view an osteosarcoma? When should an MRI be done?
- Can see extent of intramedullary tumor, extent and position of soft tissue mass, relation of tumor to N-V structuers.
- Can see vascularity of tumor
- Presence of skip metastases
Perform prior to biopsy and after preoperative chemo.
Why would a CT scan be used to view an osteosarcoma? When it is used?
For preoperative staging
Determines presence of pulmonary metastatic disease
Occasional use when MRI not effective (ie metallic implants)
What are signs and symptoms of an osteosarcoma?
Pain: initially intermittent activity related, later present at rest
Soft tissue mass - swelling from venous/lymph obstruction
Reactive joint effusion
Pathologic fracture-rare (image)
Decreased ROM
What laboratory findings are seen with osteosarcoma?
Alkaline phosphatase will be elevated in 50% of cases - it’s osteoblast induced and comes from the liver. Will diminish with treatment.
CBC: anemia is a late sign. Indicative of disseminated disease (3rd world)
What is the gross and histologic findigs seen with osteosarcoma?
Malignant spindle cells, hypercellularity, and pleomorphic cells. Mitosis.
- Production of osteoid MUST be present. Chondroblastic and fibroblastic areas.
Gross: extension within intramedullary canal, extension through cortex, bone formation. Areas of necroses, cysts, and hemmorhage.
How would you diagnose an osteosarcoma?
Biopsy - histiologic sample to confirm diagnosis
Baseline histology: post-chemotherapy comparisons.
How would you treat osteosarcoma?
- Pre-op neo-adjuvant multi-agent chemo.
- Pre-op restaging
- Post-op multi agent chemo
- Vigorous surveillance post-treatment
Multi-agent neo-adjuvant chemo has allowed a high survival rate.
What types of chemo are used to treat osteosarcoma?
- Doxorubicin/adriamycin
- HD Methotrexate w/ leukovorin rescue
- Cisplatin
- Ifosfamide
Osteosarcomas most commonly metastasize to where?
LUNGS
What are two types of benign soft-tissue lesions?
Hemangioma and neurulemoma (schwannoma)
What is a neurilemma (schwannoma)? Who does it occur in?
A peripheral nerve tumors that develops from the peripheral schwann cell.
Slow growing, occurs equally in males and females, ages 20-60.
Nerves can be preserved with marginal resection.
What is the appearance of a neurilemoma?
Benign tumor with palisading spindle cells.
What are the most common types of soft tissue sarcomas?
- Liposarcoma
- Undifferentiated pleomorphic sarcoma (UPS)
- Fibrosarcoma
- Leiomyosarcoma
- Synovial sarcoma
- Rhabdomyosarcoma
What is the range of diagnosis for soft tissue sarcomas? Describe the grading.
- Low grade malignancy
- Intermediate grade myxoid liposarcoma
- High grade de-differentiated sarcoma or undiffereneicated pleomorphic sarcoma.
Grade based on histology - pleomorphic cells with high mitotic rate and areas of necrosis
Where do soft tissue sarcomas occur in the body and who gets them?
Can occur anywhere; 60% occur in extremities (3/4 in lower)
- remaining in the abdoman and RP, chest, and H&N.
All ages, increasing incidence with increasing age. Slightly more predom in males.
___% of patients with soft tissue sarcomas have mets at the time of presentation.
10%
Most soft tissue sarcomas metastasize where?
To the lungs - mets tend to be more peripheral than primary tumors of the lung.
What types of histologic soft tissue tumors will go to the lymph nodes?
Synovial sarcoma
Epithelioid sarcoma
Clear cell sarcoma
Rhabdomyosarcoma
How would you physically examine a soft tissue tumor? What questions would you ask?
Fixed to underlying structures or freely mobile?
Warmth or redness?
Thrill or bruit?
Tenderness or neurologic symptoms.
Why might you use an MRI to view a soft tissue tumor?
Superior soft tissue contrast; Multi-planar images without loss of clarity
- Use of multiple sequences and gadolinium helps differentiate tumors from necrosis and edema.
- Helps eval surrounding vessels
What is the value of dong a CT scan of the chest, abdomen, and pelvis to stage a soft tissue tumor?
Allows you to evaluate the lungs, retroperitoneum, and lymph nodes.
Detects clcifications or ossification in a STS (soft tissue tumor)
It also allows for visualization and guidance of percutaneous biopsies.
What is the value of ultrasound in staging soft tissue tumors?
Used to guide biopsy: core needle biopsy in 98% of biopsies.
Helpful in characterizing suspected vascular lesions; assists in localizing lesions adjacent to vascular structures.
What is a PET scan? How does it work?
Positron Emission Tomography: based on rate of glucose metabolism by tumors. Once in cells by glucose transport, it’s phosphorylated by the cells. Glucose in this form is trapped in the cells and easily detected.
- Detected FDG is a quantatative measure of tumor activity.
What is the use of PET scans in soft tissue tumors?
Determines grade of tumor - higher grade has more activity
Reponse of tumor to adjuvant therapies (chemo/radiation)
Detects local recurrences and metastatic disease.
What is the function of biopsy of soft tissue tumors?
Obtain viable diagnostic tissue to confirm clinical suspicion
Minimize tissue contaminaton and goes directly to tumor.
Be sure the pathologist can make the diagnosis based on your sample.
How are biopsies performed?
CT direct; percutaneous. Performed through trocar: multiple passes through one hole.
Performed by MSK radiolgist with our consultatoin.
8-10 cores.
What is the function of immunoperoxidase staining?
Used to distinguish where the spindle cells come from.
How would you treat a high grade soft tissue sarcoma?
- Pre-op external beam radiation therapy: 5-6 weeks
- Restage lesion: CT scans of chest/abd/pelvis; MRI of extremity with and without contrast
- Resection of lesion with wide margins (normal tissue around lesions)
- Continued surveillance.
Are size and depth of lesion predictors of tumor grade of a soft tissue sarcomas?
NO!
What is imperative to do before biopsy of soft tissue sarcomas?
Staging of all tumors with imaging studies.
What are ST (soft tissue) sarcomas derived from? Who gets them and how are they named?
Mesenchyme origin.
Rare tumors, <1% of all cancers.
All age groups; named by tissues/cells of origin.
Size and depth aren’t always predictor of histoloy or grade of tumor.
How are high grade soft-tissue sarcomas treated?
With pre-op radiation therapy and surgery.
Wide margins of resection needed.
Surgery may require rotational or free tissue flar to close defect.
Continued surveillance for recurrence/mets needed.
