Bone, cartilage, and soft tissue tumors: Clinical Correlations

Question 1

Common Bone Lesions

Answer 1

1. Metastatic carcinoma
2. Multiple myeloma
3. Lymphoma of bone
4. Osteosarcoma
5. Ewing sarcoma
6. **Unicameral bone cyst (UBC)**
7. Aneurysmal bone cyst (ABC)*
8. Enchondroma
9. Osteochondroma
10. Chondrosarcoma

Question 2

Soft Tissue Lesions

Answer 2

1. Lipoma
2. Desmoid
3. Soft tissue sarcoma
4. Lymphoma

Question 3

72 y/o F presents with L knee pain: Based on the image, what is the differential?

Answer 3

1. Multiple Myeloma
2. Lymphoma
3. Bone Sarcoma
4. Metastatic Disease

Question 4

What is the most likely diagnosis?

Answer 4

Multiple Myeloma

Question 5

When staging a bone lesion, what should you consider?

Answer 5

• X-ray of entire affected bone
• Whole body bone scan (or skeletal survey)
• CT scan of chest, abdomen, and pelvis OR or PET/CT
• Serum Protein Electrophoresis /Urine Protein Electrophoresis /serum free light chains (for multiple myeloma or plasmacytoma)
• Prostatic specific antigen (for prostate adenocarcinoma)

Question 6

What is the most likely disease?

Answer 6

Multiple Myeloma

Question 7

Multiple Myeloma:

Characteristics

Answer 7

• A common lymphoid malignancy
  
  • Sheets of plasma cells with atypical cell features
• Median age is 70 years
• Principally involves bone marrow and causes lytic lesions throughout skeleton
  
  • most commonly vertebrae, ribs, skull, pelvis, femur, clavicle, & scapula
• Result in “pathologic fractures”
• Cells produce a monoclonal immuno- globulin, most often IgG

Question 8

What is the most likely diagnosis?

Answer 8

B cell lymphoma

Question 9

What is the marker that would indicate this is B cell lymphoma?

Answer 9

CD20

Question 10

What does this image suggest?

Answer 10

Osteosarcoma

Question 11

Osteosarcoma histology

Answer 11

Osteosarcoma histology

Question 12

Metastatic poorly differentiated adenocarcinoma, consistent origin in a primary lung adenocarinoma:

What are the markers?

Answer 12

• Lung adenocarcinomas: one of four major types of lung carcinoma
  
  • Most common type of lung cancer in woman and nonsmokers
  • Metastases early (to bone, brain, and liver)

Clinical Markers

1. TTF1: positive in adenocarcinomas arising in the lungs
2. Cytokeratin: positive in carcinomas

Question 13

Childhood lesions of bone:

Answer 13

1. Osteochondroma
2. Enchondroma
3. Unicameral bone cyst
4. Aneurysmal bone cyst
5. Ewing sarcoma
6. Osteosarcoma

Question 14

10 y/o male presents with bone pain: What is the differential diagnosis?

Answer 14

1. UBC- Unicameral Bone Cyst
2. ABC- Aneurysmal Bone Cyst
3. Giant Cell Tumor of Bone
4. Osteosarcoma
5. Ewing Sarcoma

Question 15

What is the most likely diagnosis?

Answer 15

Unicameral Bone Cyst (UBC)

Question 16

Unicameral Bone Cyst:

Characteristics

Answer 16

AKA: Solitary cyst or Simple Bone Cyst

• Benign
• Children & young adults
• Metaphyseal region of long bones
• Usually proximal femur or humerus
• Presentation: pathologic fracture
• Bone cortex is eroded by cyst & elicits secondary periosteal new bone formation
• Pathology: cyst filled with clear fluid & lined with thin fibrous membrane
• Because of frequent fractures: old blood (hemosiderin) and granulation tissue maybe present

Question 17

What is the most likely diagnosis?

Answer 17

Aneurysmal Bone Cyst (ABC)

NOTE THE FLUID-FLUID LEVELS

Question 18

Aneurysmal Bone Cyst (ABC):

Characteristics

Answer 18

• Eccentric solitary expansile lesion
• Mostly < 20 years
• Swelling, pain, or tenderness
• Metaphyseal region of long bones: common
  
  • But any bone may be involved
• Cystic spaces filled with blood, but no endothelial cell lining
• Between blood filled spaces are fibrous septa, giant cells & immature bone or osteoid
• Recently discovered that it is a benign neoplasm with a characteristic translocation

Question 19

Aneurysmal Bone Cyst:

Treatment

Answer 19

1. Curettage (it may recur)
2. Embolization/sclerotherapy

Question 20

What is the most likely diagnosis?

(pure lytic lesion in the epiphysis)

Answer 20

Giant Cell Tumor of Bone

Question 21

What is the most likely diagnosis?

Answer 21

Osteosarcoma

mineralization in bone = osteosarcoma

Question 22

What is the most likely diagnosis

(10 y/o male with bone pain)

Answer 22

Ewing Sarcoma

Question 23

• What is the marker for a Ewing sarcoma (+) stain?
• What is the translocation in Ewing Sarcoma?

Answer 23

• Marker: CD99
• t(11,22) (90% of cases)

Question 24

56 y/o M with Painless thigh mass: What is the differential?

Answer 24

1. Lipomas
2. Soft tissue sarcomas
3. Desmoid fibromatosis
4. Lymphoma

Question 25

What is the most likely diagnosis?

Answer 25

**Lipoma**

Question 26

What is the most likely diagnosis?

Answer 26

**Desmoid Fibromatosis**

Question 27

What is this a positive stain of?

Answer 27

**Beta Catenin (+) for Desmoid Fibromatosis**

Question 28

Biopsy from a 56 y/o M with a painless thigh mass. What is the most likely diagnosis?

Answer 28

**High-grade Undifferentiated Pleomorphic Sarcoma**

Question 29

**40 y/o F with pelvic pain and incidentally noted pelvic lesion:** What is the differential?

Answer 29

1. **Enchondroma** 2. **Osteochondroma** 3. **Chondrosarcoma**

Question 30

1. 1. Enchondroma 2. 2. Osteochondroma 3. 3. Chondrosarcoma What do they have in common?

Answer 30

**Tumors that deposit mineral**

Question 31

What is the most likely diagnosis?

Answer 31

**Enchondroma**

Question 32

What is the most likely diagnosis?

Answer 32

**Osteochondroma**

Question 33

What is the most likely diagnosis?

Answer 33

**Osteochondroma**

Question 34

**40 y/o F with pelvic pain and incidentally noted pelvic lesion.** She also presents with this histological stain. ## Footnote **What is the most likely diagnosis?**

Answer 34

**Chondrosarcoma**