Bone Tumors Practice Questions

Q: A 14 year old male presents with mushroom like tumor in the distal femur for past 2 years. Which of the following features suggest malignant transformation?

Cartilage cap thickness $>3 \mathrm{~cm}$. ***Cartilage thickness >2 cm*** - A **cartilage cap thickness greater than 2 cm** in an osteochondroma in an adult (or >3 cm in children) is a strong indicator of **malignant transformation** into a secondary peripheral **chondrosarcoma**. [2], [3] - **Key imaging finding:** Cartilage cap measured on MRI or CT scan - Other features suggesting malignant transformation include continued growth after skeletal maturity, new or increasing pain, cortical destruction, and new soft tissue mass. [2], [3] *Presence of cartilage cap* - All osteochondromas have a cartilage cap by definition - this is a normal feature, not a sign of malignancy. [1] - The **thickness** of the cap, not its presence, is what matters. *Location in metaphysis* - Osteochondromas typically arise from the metaphysis near the growth plate - this is a normal location. [3] - Location alone does not indicate malignant transformation. *Size less than 1 cm* - Small size suggests a benign, stable lesion. - Malignant transformation is suggested by **increasing size** and growth after skeletal maturity, not small size. [2] **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1202. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 672-673. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1202-1204.

Q: Adamantinoma affects

Tibia. ***Tibia*** - **Adamantinoma** is a rare, malignant bone tumor that almost exclusively affects the **tibia**, accounting for over 90% of cases. - It often presents as a **slow-growing mass** associated with pain and swelling in the shin. *Humerus* - While other primary bone tumors can affect the humerus, adamantinoma is **extremely rare** in this location. - The humerus is more commonly affected by tumors like **osteosarcoma** or **Ewing sarcoma**. *Femur* - The femur is a common site for various bone tumors, but **adamantinoma is not typically found** here. - Tumors like **osteosarcoma** and **chondrosarcoma** are much more prevalent in the femur. *Radius* - Similar to the humerus and femur, the radius is **not a characteristic location** for adamantinoma. - Tumors of the radius are generally less common than in the major long bones.

Q: A patient presents with pain in the thigh, relieved by aspirin. X-ray shows a radiolucent mass surrounded by sclerosis. Diagnosis is ?

Osteoid osteoma. ***Osteoid osteoma*** - Characterized by **pain that is classically relieved by aspirin or NSAIDs**, due to high prostaglandin production within the lesion. - Radiographically, it appears as a **small radiolucent nidus (lesion) less than 2 cm**, surrounded by a dense sclerotic bone reaction. *Osteoma* - This is a **benign tumor of mature bone**, most commonly found on the skull and facial bones. - It typically presents as a **hard, solitary, immobile mass** and is usually asymptomatic, not causing pain relieved by aspirin. *Osteoclastoma* - Also known as a **giant cell tumor of bone**, it is a locally aggressive tumor. - It typically affects the **epiphysis and metaphysis of long bones** (e.g., around the knee) and is not characteristically relieved by aspirin. *Osteoblastoma* - This is a **larger variant of osteoid osteoma** (>2 cm), also bone-forming, but the pain is generally less responsive to aspirin, and it tends to be more aggressive. - It is more commonly found in the **spine and sacrum**, unlike the thigh in this case.

Q: Soap bubble appearance on X-ray is seen in which bone tumor?

Giant cell tumor. ***Giant cell tumor*** - The **soap bubble appearance** on X-ray is a classic radiographic finding for **giant cell tumors**, indicating areas of bone destruction and new bone formation. - These tumors are typically **benign but locally aggressive** and are commonly found in the **epiphyseal and metaphyseal regions** of long bones. *Osteogenic sarcoma* - Characterized by a more aggressive appearance on X-ray, often with a **sunburst pattern** or **Codman's triangle**, indicating periosteal reaction. - This is a **highly malignant tumor** of bone-forming tissue, not typically associated with a "soap bubble" appearance. *Multiple myeloma* - Presents on X-ray with characteristic **punched-out lytic lesions** in multiple bones, especially the skull, spine, and pelvis. - It does not usually form the multi-loculated, expansile lesions that create a "soap bubble" appearance. *Chondroblastoma* - Often appears as a **well-defined lytic lesion** with a thin sclerotic rim and is typically found in the **epiphysis** of long bones. - While it can be destructive, it usually doesn't produce the multi-loculated, expansile "soap bubble" pattern seen with giant cell tumors.

Q: A 10-year child presented with a mid tibial swelling and severe localized nocturnal pain relieved by NSAIDs. An x-ray revealed a lytic lesion with a small cortical nidus and surrounding reactive sclerosis. What is the most likely diagnosis?

Osteoid osteoma. ***Osteoid osteoma*** - A lytic lesion with **sclerotic margins** on an X-ray in a child, particularly in the tibia, is highly characteristic of an **osteoid osteoma**. - This benign bone tumor classically presents with **severe localized nocturnal pain relieved by NSAIDs**, which is a hallmark feature of osteoid osteoma, and the radiological findings of a small cortical nidus with surrounding reactive sclerosis are strongly suggestive. *Eosinophilic granuloma* - While it can present as a **lytic lesion** in bone, it typically lacks the prominent **sclerotic margins** seen in osteoid osteoma. - It's a form of **Langerhans cell histiocytosis** and can be solitary or multifocal, affecting various bones including the skull and long bones. *Fibrocortical defect* - Also known as **non-ossifying fibroma** or **fibrous cortical defect**, this is a common benign lesion, often found incidentally. - It appears as a **well-defined eccentric lytic lesion** in the metaphysis of long bones, but its margins are typically **thinly sclerotic** or appear as a "bubbly" lesion, not the strong sclerosis seen here. *Fibrous dysplasia* - Characterized by the replacement of normal bone with **fibrous tissue** and immature bone, leading to a **ground-glass appearance** on X-ray. - While it can cause lytic lesions, it does not typically present with the distinct **sclerotic margins** associated with osteoid osteoma in a solitary lesion.

Q: A child 10 yrs of age presents with a mass on his left thigh. The mass seems to be arising from the diaphysis of the femur and involving the soft tissue of the thigh. The child is having fever also. Give your most probable diagnosis -

Ewing's sarcoma. ***Ewing's sarcoma*** - **Ewing's sarcoma** commonly presents in children and adolescents, often involving the **diaphysis of long bones** like the femur. - The presence of a **soft tissue mass** and **fever** are characteristic systemic symptoms due to its aggressive nature and rapid growth. *Osteosarcoma* - While it is a common pediatric bone tumor, **osteosarcoma** typically arises in the **metaphysis** of long bones, not the diaphysis. - Systemic symptoms like fever are less common at presentation compared to Ewing's sarcoma unless there's significant metastatic disease. *Chondrosarcoma* - **Chondrosarcoma** is a malignant tumor of cartilage that usually affects older adults and rarely occurs in children. - It typically affects the **pelvis, shoulder, or long bones**, but a fever and involvement of the soft tissue with a diaphyseal origin are less classic presentation. *Malignant fibrous histiocytoma* - **Malignant fibrous histiocytoma** (now often termed undifferentiated pleomorphic sarcoma) is a tumor of adulthood, primarily affecting individuals over 40 years of age. - While it can involve deep soft tissues and bone, it is an extremely rare diagnosis in a 10-year-old child.

Q: Classification system of bone tumors is -

Enneking. ***Enneking*** - The **Enneking staging system** is widely used for primary **bone tumors**, particularly sarcomas. - It classifies tumors based on their histological grade, local extension, and presence of metastases, which guides surgical planning and prognosis. *Edmonton* - The **Edmonton classification** is primarily used for **periprosthetic fractures** around hip and knee replacements. - It does not classify primary bone tumors but rather describes fracture patterns related to prosthetic implants. *TNM* - The **TNM (Tumor, Node, Metastasis)** classification is a general staging system used for many types of cancer, but it's not the primary system for bone tumors. - While applicable for some bone cancers, the **Enneking system** provides a more specific functional and anatomical assessment for limb-sparing surgery in bone sarcomas. *Manchester* - The **Manchester staging system** is primarily used for **lymphoma**, particularly Hodgkin lymphoma. - It describes the extent of lymph node involvement and extralymphatic disease, completely unrelated to bone tumors.

Q: A 20-year old male patient presents with pain on movement. X-ray of knee joint shows lytic lesion on the upper end of tibia. What is the likely diagnosis?

Osteoclastoma. **Osteoclastoma** - An **osteoclastoma**, also known as a **giant cell tumor of bone**, typically presents in young adults (20-40 years old) and is characterized by a **lytic lesion** often located in the **epiphysis or metaphysis** of long bones, particularly around the knee joint (distal femur or proximal tibia). - These tumors are locally aggressive and can cause pain and swelling. *Simple bone cyst* - A **simple bone cyst (unicameral bone cyst)** is usually found in younger individuals (under 20) and is a **fluid-filled lesion** that often appears as a **central, expansile lytic lesion** in the **metaphysis** of long bones, commonly the proximal humerus or femur, not typically the epiphysis. - These are often painless and discovered incidentally or due to a pathological fracture. *Multiple myeloma* - **Multiple myeloma** is a plasma cell malignancy primarily affecting older adults (typically >50 years old) and presents with **multiple "punched-out" lytic lesions** in various bones (skull, spine, ribs, pelvis), rather than a solitary lytic lesion in a young adult. - It is associated with systemic symptoms such as anemia, hypercalcemia, renal failure, and abnormal immunoglobulins. *Adamantinoma* - An **adamantinoma** is a rare, malignant bone tumor that almost exclusively occurs in the **tibia**, but it typically presents as a **lytic, often eccentric lesion with sclerotic margins** and occasionally a "soap bubble" appearance, and while it occurs in young adults, it is a very rare diagnosis compared to osteoclastoma for a knee lytic lesion. - It often has a characteristic histological appearance resembling epithelial tissue.

Q: A child presented in the OPD with multiple permeating lesions involving all the bones of the body. Which of the following is the most probable diagnosis?

Histiocytosis X. ***Histiocytosis X*** - **Histiocytosis X**, now known as **Langerhans cell histiocytosis (LCH)**, can present with lytic bone lesions, which may be widespread and "permeating" throughout the skeletal system in children. - The disease involves the proliferation of **Langerhans cells**, and bone involvement is a common manifestation, leading to multiple osteolytic lesions. *Neuroblastoma* - **Neuroblastoma** is a common childhood cancer that frequently metastasizes to bone, leading to lytic lesions; however, it often presents with other symptoms like an abdominal mass, opsoclonus-myoclonus syndrome, or proptosis due to orbital involvement. - While bone metastases can be extensive, the primary tumor is typically extraosseous, originating from neural crest cells. *Metastasis from Wilm's tumour* - **Wilms' tumor** primarily affects the kidney and typically metastasizes to the lungs, liver, and occasionally bone marrow. - While bone metastasis can occur, it's less common than in neuroblastoma and less likely to present as widespread "permeating" osseous lesions throughout all bones, as described. *Metastasis from osteosarcoma* - **Osteosarcoma** is a primary malignant bone tumor, and its metastases usually occur in the lungs. - While it can metastasize to other bones, it generally presents as new, discrete osteoblastic or mixed lesions rather than a widespread permeating pattern across the entire skeletal system.

Question 1

A 14 year old male presents with mushroom like tumor in the distal femur for past 2 years. Which of the following features suggest malignant transformation?

Accepted Answer

Cartilage cap thickness $>3 \mathrm{~cm}$

Answer

Location in metaphysis

Answer

Size less than 1 cm

Answer

Presence of cartilage cap

Question 2

Adamantinoma affects

Accepted Answer

Tibia

Answer

Humerus

Answer

Femur

Answer

Radius

Question 3

A patient presents with pain in the thigh, relieved by aspirin. X-ray shows a radiolucent mass surrounded by sclerosis. Diagnosis is ?

Accepted Answer

Osteoid osteoma

Answer

Osteoma

Answer

Osteoclastoma

Answer

Osteoblastoma

Question 4

Soap bubble appearance on X-ray is seen in which bone tumor?

Accepted Answer

Giant cell tumor

Answer

Osteogenic sarcoma

Answer

Multiple myeloma

Answer

Chondroblastoma

Question 5

A 10-year child presented with a mid tibial swelling and severe localized nocturnal pain relieved by NSAIDs. An x-ray revealed a lytic lesion with a small cortical nidus and surrounding reactive sclerosis. What is the most likely diagnosis?

Accepted Answer

Osteoid osteoma

Answer

Eosinophilic granuloma

Answer

Fibrocortical defect

Answer

Fibrous dysplasia

Question 6

The signs of malignant transformation in osteochondroma are all except

Accepted Answer

Weight loss

Answer

Increase in thickness of cartilage cap

Answer

Increase in size

Answer

Pain

Question 7

A child 10 yrs of age presents with a mass on his left thigh. The mass seems to be arising from the diaphysis of the femur and involving the soft tissue of the thigh. The child is having fever also. Give your most probable diagnosis -

Accepted Answer

Ewing's sarcoma

Answer

Osteosarcoma

Answer

Chondrosarcoma

Answer

Malignant fibrous histiocytoma

Question 8

Classification system of bone tumors is -

Accepted Answer

Enneking

Answer

Edmonton

Answer

TNM

Answer

Manchester

Question 9

A 20-year old male patient presents with pain on movement. X-ray of knee joint shows lytic lesion on the upper end of tibia. What is the likely diagnosis?

Accepted Answer

Osteoclastoma

Answer

Simple bone cyst

Answer

Multiple myeloma

Answer

Adamantinoma

Question 10

A child presented in the OPD with multiple permeating lesions involving all the bones of the body. Which of the following is the most probable diagnosis?

Accepted Answer

Histiocytosis X

Answer

Neuroblastoma

Answer

Metastasis from Wilm's tumour

Answer

Metastasis from osteosarcoma

Bone Tumors — MCQs

Bone Tumors — MCQs

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