Bone neoplasms

Question 1

What are the two main categories of bone tumors?

Answer 1

Primary bone tumors and metastatic bone tumors, with metastatic being more common.

Question 2

What is the most common primary malignant bone tumor?

Answer 2

Osteosarcoma (35%), followed by chondrosarcoma (25%) and Ewing sarcoma (16%).

Question 3

What are common clinical features of primary malignant bone tumors?

Answer 3

Pain, swelling, fracture, and loss of function; 20-25% present with metastasis.

Question 4

What imaging modalities are commonly used to assess bone tumors?

Answer 4

X-ray, MRI or CT, bone scans, PET scans, and biopsy for definitive diagnosis.

Question 5

What age group is primarily affected by osteosarcoma?

Answer 5

Mostly children and young adults, ages 10-25.

Question 6

Describe the typical appearance of osteosarcoma on X-ray.

Answer 6

A large, destructive, lytic or blastic mass with a sunburst pattern, often breaking through the cortex.

Question 7

At what age is chondrosarcoma most commonly seen?

Answer 7

Ages 30-60, more common in males.

Question 8

What are the key macroscopic features of chondrosarcoma?

Answer 8

Large, lobulated, pearly white or light blue tumors, often with calcifications and myxoid changes.

Question 9

What is the common age and location for giant cell tumors?

Answer 9

Ages 30-50, often in the epiphyseal-metaphyseal region of long bones, especially around the knee.

Question 10

Describe the histological appearance of giant cell tumors.

Answer 10

Numerous multinucleated giant cells with stromal cells that resemble the giant cells; no osteoid formation.

Question 11

What is fibrous dysplasia, and how does it present?

Answer 11

A benign tumor from developmental arrest, presenting as monostotic or polyostotic lesions, sometimes in syndromic forms like McCune-Albright syndrome.

Question 12

What mutation is associated with fibrous dysplasia?

Answer 12

Somatic gain-of-function mutation in the GNAS1 gene.

Question 13

List types of bone tumors by lineage classification.

Answer 13

Osteogenic tumors (e.g., osteosarcoma)
Cartilage tumors (e.g., chondrosarcoma, chondroma)
Fibrogenic (e.g., fibrous dysplasia)
Ewing sarcoma/PNET
Giant cell-rich tumors (e.g., giant cell tumor)
Vascular tumors (e.g., angiosarcoma)
Miscellaneous (e.g., Langerhans cell histiocytosis)

Question 14

What are key prognostic factors for primary malignant bone tumors?

Answer 14

Tumor size, histopathologic grading, tumor location, metastasis presence, and response to chemotherapy (specific to osteosarcoma and Ewing sarcoma).

Question 15

What are the differences between osteoid osteoma and osteoblastoma?

Answer 15

Both are benign, osteogenic tumors, but osteoid osteoma is usually smaller (<2 cm) and causes significant pain often relieved by NSAIDs, while osteoblastoma is larger, less painful, and commonly found in the spine.

Question 16

What is Chondromyxoid Fibroma?

Answer 16

A rare benign cartilage tumor that presents as a painful lesion, often located in the metaphysis of long bones, especially in young adults.

Question 17

How is Chondromyxoid Fibroma differentiated from other cartilage tumors?

Answer 17

It shows a mix of chondroid, myxoid, and fibrous areas and is usually found in metaphyseal regions of long bones.

Question 18

What are the different types of chondroma?

Answer 18

Enchondroma (within the bone), subperiosteal chondroma (on the bone surface), and soft tissue chondroma (in soft tissue without bone contact).

Question 19

What conditions are associated with multiple enchondromas?

Answer 19

Ollier’s disease and Maffucci syndrome, with enchondromas located in multiple bones.

Question 20

What is Ewing Sarcoma, and what age group does it primarily affect?

Answer 20

A highly malignant small round cell tumor primarily affecting children and young adults, with common sites including the pelvis, femur, and ribs.

Question 21

What genetic abnormality is associated with Ewing Sarcoma?

Answer 21

A translocation between chromosomes 11 and 22 [t(11;22)], creating an EWS-FLI1 fusion gene, which aids in diagnosis.

Question 22

What is an osteochondroma?

Answer 22

A common benign bone tumor with a cartilage cap, arising as an exostosis attached to the bone by a bony stalk.

Question 23

What genetic mutations are associated with multiple hereditary osteochondromas?

Answer 23

Mutations in EXT1 and EXT2 genes.

Question 24

What factors are used to grade chondrosarcoma?

Answer 24

Cellular density, nuclear atypia, and mitotic activity of chondrocytes, with grades ranging from well to poorly differentiated (Grade 1-3).

Question 25

Why is grading important in chondrosarcoma?

Answer 25

Higher-grade chondrosarcomas are more aggressive, with increased likelihood of metastasis to the lungs.

Question 26

What is a giant cell reparative granuloma?

Answer 26

A benign reactive lesion often found in the jaw and small bones of the hands and feet, containing numerous giant cells in a fibrous stroma.

Question 27

What are common types of vascular tumors in bone?

Answer 27

Angiosarcoma (malignant), epithelioid hemangioendothelioma (EHE), and benign hemangiomas

Question 28

How is angiosarcoma identified in bone?

Answer 28

It is a highly aggressive tumor with vascular differentiation, often presenting as painful, lytic lesions.

Question 29

What is Langerhans Cell Histiocytosis, and how does it affect bone?

Answer 29

A disorder where Langerhans cells proliferate abnormally, causing lytic bone lesions, often in children and commonly affecting the skull, pelvis, and long bones.

Question 30

What are two syndromes associated with polyostotic fibrous dysplasia?

Answer 30

Mazabraud syndrome (with soft tissue myxomas) and McCune-Albright syndrome (associated with café-au-lait spots and endocrine abnormalities like precocious puberty).

Question 31

What are some subtypes of osteosarcoma?

Answer 31

Conventional (most common), telangiectatic, parosteal, periosteal, and high-grade surface osteosarcomas, each with unique radiological and histological features.

Question 32

Which subtype of osteosarcoma has a better prognosis?

Answer 32

Parosteal osteosarcoma generally has a better prognosis compared to other high-grade types due to its low-grade, slow-growing nature.

Question 33

What is a key histological feature of osteosarcoma?

Answer 33

The presence of a lace-like pattern of osteoid (immature bone matrix) produced by malignant cells.

Question 34

What radiological sign is commonly associated with osteosarcoma?

Answer 34

The “sunburst” pattern, resulting from periosteal reaction and new bone formation in soft tissue.

Question 35

What is the clinical presentation of chondrosarcoma?

Answer 35

Progressive pain, swelling, and sometimes a palpable mass, often affecting long bones, pelvis, and ribs.

Question 36

Why is chondrosarcoma typically not treated with chemotherapy?

Answer 36

Chondrosarcoma is relatively chemo-resistant; treatment often relies on surgical resection.

Question 37

How can enchondroma be differentiated from low-grade chondrosarcoma?

Answer 37

Enchondromas are benign, often asymptomatic, and slow-growing, while chondrosarcomas show aggressive features such as pain, cortical destruction, and permeative growth.

Question 38

What is a distinguishing feature of giant cell tumors on imaging?

Answer 38

Eccentric, lytic lesions typically located in the epiphysis of long bones with a “soap bubble” appearance.

Question 39

Why is giant cell tumor considered benign but locally aggressive?

Answer 39

It can cause significant bone destruction and has a high recurrence rate, but metastasis is rare.

Question 40

What is a characteristic microscopic feature of fibrous dysplasia?

Answer 40

“Chinese character” trabeculae—curvilinear, woven bone spicules within a fibrous stroma without osteoblastic rimming.

Question 41

What distinguishes polyostotic fibrous dysplasia from monostotic?

Answer 41

Polyostotic affects multiple bones and may be associated with syndromic presentations, while monostotic affects a single bone.

Question 42

What is adamantinoma, and where is it typically found?

Answer 42

A rare, low-grade malignant bone tumor, commonly found in the tibia, characterized by epithelial-like cells in a fibrous stroma.

Question 43

How is adamantinoma distinguished from osteofibrous dysplasia?

Answer 43

Adamantinoma is locally aggressive and may metastasize, whereas osteofibrous dysplasia is benign and non-metastasizing.

Question 44

What is a key histological feature of Langerhans Cell Histiocytosis in bone?

Answer 44

Presence of Langerhans cells with characteristic “coffee bean” nuclei and eosinophilic cytoplasm, often accompanied by eosinophils.

Question 45

How does Langerhans Cell Histiocytosis present clinically?

Answer 45

Bone pain and lytic lesions, commonly in children, affecting sites like the skull, pelvis, and long bones.

Question 46

What is the typical presentation of a hemangioma in bone?

Answer 46

A benign, usually asymptomatic vascular tumor, often incidental on imaging with a “honeycomb” or “polka-dot” appearance.

Question 47

Where are bone hemangiomas most commonly located?

Answer 47

Vertebrae and skull.

Question 48

What is epithelioid hemangioendothelioma (EHE)?

Answer 48

: A rare, low-to-intermediate grade malignant vascular tumor affecting bones, with potential for metastasis.

Question 49

Which bones are commonly affected by EHE?

Answer 49

Often occurs in long bones, pelvis, and spine, presenting with pain and swelling.

Question 50

How does multiple myeloma typically affect bones?

Answer 50

Causes lytic “punched-out” lesions, bone pain, and increased fracture risk due to osteoclast activation and bone resorption.

Question 51

What is a common laboratory finding in multiple myeloma?

Answer 51

Elevated monoclonal protein in serum or urine (M-protein) and hypercalcemia.

Question 52

What are common primary cancers that metastasize to bone?

Answer 52

Breast, prostate, lung, kidney, and thyroid cancers

Question 53

How does metastatic bone disease typically present?

Answer 53

Pain, pathological fractures, and hypercalcemia due to osteolytic or osteoblastic lesions.