Bone and Soft Tissue Pathology Practice Questions

Q: Which of the following is a differential of giant cell tumor?

Chondroblastoma. **Chondroblastoma** - Both **Chondroblastoma** and **giant cell tumor (GCT)** are epiphyseal lesions that can occur in a similar age group and have some overlapping radiographic features, making them a differential. - Histologically, chondroblastoma can contain **multinucleated giant cells**, which may be confused with those found in GCT. *Osteogenic sarcoma* - **Osteogenic sarcoma (osteosarcoma)** is a malignant bone tumor primarily affecting the metaphysis of long bones, in contrast to GCT's epiphyseal location [1]. - Radiographically, osteosarcoma often presents with an aggressive, destructive pattern including **periosteal reaction** (e.g., sunburst, Codman's triangle), which is less typical for GCT [1]. *Ossifying fibroma* - **Ossifying fibroma** is a benign fibro-osseous lesion most commonly found in the jaws, distinctly different from GCT's predilection for epiphyses of long bones. - Histologically, it's characterized by the presence of **mineralized material** resembling bone or cementum within a fibrous stroma, unlike the abundant multinucleated giant cells of GCT [1]. *Non-ossifying fibroma* - A **non-ossifying fibroma (NOF)**, also known as a fibrous cortical defect, is typically a benign, asymptomatic, and self-limiting lesion found in the metaphysis of long bones, usually in children and adolescents. - It is characterized by **fibrous tissue** and foam cells but lacks the prominent multinucleated giant cells and epiphyseal location characteristic of GCT [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1205-1206. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1208.

Q: All of the following are seen in osteopetrosis EXCEPT:

Decreased bone density. ***Decreased bone density*** - Osteopetrosis is characterized by **increased bone density**, not decreased, due to the failure of osteoclasts to resorb bone, leading to accumulation of dense, immature bone [1]. - This creates the classic "**marble bone**" or "**stone bone**" appearance on radiographs [1]. - Therefore, decreased bone density is **contradictory** to the fundamental pathology of the disorder. *Osteomyelitis of the mandible* - Defective **osteoclast function** in osteopetrosis leads to **dense, brittle bone** with **compromised vascularity** that is highly susceptible to infection, particularly in the mandible and maxilla. - The poor blood supply and altered bone architecture make these bones prone to **osteonecrosis** and subsequent infection, manifesting as osteomyelitis. - This is a **well-recognized complication** of osteopetrosis. *Compression of cranial nerve* - **Cranial nerve compression** is a **major complication** of osteopetrosis due to **narrowing of skull foramina** from excessive bone formation [1]. - Common manifestations include **optic nerve compression** (leading to blindness), **facial nerve palsy**, and **hearing loss** from auditory nerve compression [1]. - This occurs due to encroachment of dense bone on nerve pathways [1]. *Pancytopenia* - **Pancytopenia** is a **classic finding** in osteopetrosis due to the **obliteration of bone marrow space** by unresorbed primary spongiosa, impairing hematopoiesis [1]. - This leads to compensatory **extramedullary hematopoiesis** in the liver and spleen. - Bone marrow failure is a significant feature requiring bone marrow transplantation in severe cases. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1188-1189.

Q: Which of the following can histologically mimic Giant cell tumor due to presence of osteoclast-like giant cells?

Osteosarcoma. ***Osteosarcoma (Giant cell-rich variant)*** - **Giant cell-rich osteosarcoma** is a histological variant that contains numerous osteoclast-like giant cells, which can closely mimic benign giant cell tumor - Key differentiating features include **malignant osteoid production** [3], nuclear atypia in mononuclear cells, and atypical mitoses - Radiological correlation and careful histological examination of the mononuclear stromal cells are essential for accurate diagnosis *Chondroblastoma* - While this benign epiphyseal tumor does contain multinucleated giant cells, its **chondroid matrix** and characteristic **chicken-wire calcification** pattern readily distinguish it from giant cell tumor - Predominantly affects the epiphysis of skeletally immature patients *Ossifying fibroma* - A benign fibro-osseous lesion of the **craniofacial bones** with fibrous tissue and woven bone formation - Does not typically contain the abundant osteoclast-like giant cells characteristic of giant cell tumor *Non-ossifying fibroma* - A common benign fibrous lesion found in the **metaphysis** of long bones in children [2] - Contains spindle cells and foamy macrophages but **lacks the prominent osteoclast-like giant cells** [2] seen in giant cell tumor [1] **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1205-1206. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1208. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 673-674.

Q: Which bone tumor involves the epiphysis?

Giant cell tumor. ***Giant cell tumor*** - **Giant cell tumor (GCT)**, also known as osteoclastoma, characteristically arises in the **epiphysis** [1] or **metaphysis** of long bones in adults. - It is a benign but locally aggressive tumor that often presents with pain, swelling, and reduced range of motion in the affected joint [1]. *Osteosarcoma* - **Osteosarcoma** typically arises in the **metaphysis** of long bones, particularly around the knee (distal femur, proximal tibia). - It is a highly malignant primary bone tumor characterized by the production of **osteoid** by tumor cells [2]. *Ewing's sarcoma* - **Ewing's sarcoma** most commonly affects the **diaphysis** of long bones or flat bones (e.g., pelvis, scapula, ribs). - It is characterized by small, round, blue cells and often presents with pain, swelling, and systemic symptoms like fever. *Multiple myeloma* - **Multiple myeloma** is a malignancy of **plasma cells** that primarily affects the **bone marrow** and can cause widespread osteolytic lesions. - It typically presents in older adults and affects bones with active marrow, such as the vertebrae, ribs, skull, and pelvis, rather than being localized to the epiphysis as a primary bone tumor. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1205-1206. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 673-674.

Q: Premalignant bone lesion among the following is -

Pagets disease. ***Pagets disease*** - Patients with Paget's disease have an increased risk of developing **osteosarcoma** (approximately 1% of cases), making it a **classic premalignant bone lesion** [1]. - The disease involves abnormal bone remodeling, leading to weakened and enlarged bones that are more susceptible to malignant transformation. - This is the **most well-recognized premalignant bone lesion** in medical literature and the best answer. *Osteoid osteoma* - This is a **benign bone tumor** characterized by a small nidus and surrounding reactive sclerosis, causing pain that is typically relieved by NSAIDs [1]. - It has **no malignant potential** and does not transform into cancer. - This is a purely benign lesion. *Enchondroma* - An enchondroma is a **benign cartilaginous tumor** that grows within the medullary cavity of bone [2]. - **Solitary enchondromas** rarely undergo malignant transformation, though the risk exists. - **Multiple enchondromas** (Ollier's disease: 25-30% risk; Maffucci's syndrome: up to 100% risk) have significant malignant potential for transformation to **chondrosarcoma** [2]. - However, Paget's disease is more classically considered the premalignant bone lesion. *Osteochondroma* - An osteochondroma is a **benign bone tumor topped with cartilage**, growing outward from the bone surface [2]. - **Solitary osteochondromas** have a low malignant transformation risk (~1%), while **multiple hereditary exostoses** have a higher risk (3-5%) of transformation to **chondrosarcoma** [2]. - Despite this potential, it is less commonly classified as a primary premalignant lesion compared to Paget's disease. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1191-1202. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 672-673.

Q: Marble bone disease is

Osteopetrosis. ***Osteopetrosis*** - **Osteopetrosis** is also known as "marble bone disease" [1] due to the increased bone density and thickness that gives bones a marble-like appearance on X-rays [1]. - This condition results from a defect in **osteoclast function**, leading to impaired bone resorption and accumulation of immature, fragile bone [1]. *Osteomyelitis* - **Osteomyelitis** is an infection of the bone or bone marrow, typically caused by bacteria. - It does not involve a widespread increase in bone density or a marble-like appearance. *Osteogenesis imperfecta* - **Osteogenesis imperfecta** is a genetic disorder characterized by extremely fragile bones that fracture easily, often called "brittle bone disease." - It is caused by defects in **collagen production**, leading to reduced bone mass and strength, the opposite of marble bone disease. *Osteoporosis* - **Osteoporosis** is a condition characterized by decreased bone mass and density, leading to increased bone fragility and risk of fractures. - It involves a net loss of bone tissue, not increased bone density. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1188-1189.

Q: Effect of hypoparathyroidism on bones include -

None of the Above. ***None of the Above*** - **Hypoparathyroidism** leads to **decreased parathyroid hormone (PTH)** levels, resulting in **hypocalcemia** and **hyperphosphatemia**. [3] - Unlike hyperparathyroidism, which causes bone resorption, hypoparathyroidism is generally associated with **increased bone density** due to reduced osteoclastic activity. *Brown tumours* - **Brown tumors** are focal lesions caused by **osteoclastic activity** and fibrous tissue replacement in severe **hyperparathyroidism**, which is the opposite of the condition described. [1], [2] - They are a manifestation of **osteitis fibrosa cystica**, a skeletal complication of prolonged excess PTH. [2] *Subperiosteal Resorption of Bone* - **Subperiosteal bone resorption** is a classic radiographic sign of **hyperparathyroidism**, where excessive PTH causes osteoclasts to erode bone, particularly in the phalanges. [1] - This process is driven by **elevated PTH**, which is absent in hypoparathyroidism. *Multiple Cysts in Bone* - **Multiple cysts in bone** (also known as osteitis fibrosa cystica) are characteristic of **severe hyperparathyroidism**, resulting from excessive bone remodeling and fibrous tissue proliferation. [2] - Hypoparathyroidism does not cause bone cysts; instead, it tends to lead to **increased bone mineral density**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1194-1195. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1105-1106. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1106-1107.

Q: Which bone tumor occurs in the epiphysis?

Osteoclastoma. ***Osteoclastoma*** - **Giant cell tumors (osteoclastomas)** are classically located in the **epiphysis** of long bones, particularly around the knee (distal femur, proximal tibia) [1]. - They are typically benign but locally aggressive tumors, characterized by abundant **multinucleated giant cells** [1]. *Chondro-myxoid fibroma* - This is a rare, benign cartilaginous tumor that typically arises in the **metaphysis** of long tubular bones. - It consists of chondroid, myxoid, and fibrous tissue components, leading to its characteristic histological appearance. *Osteosarcoma* - **Osteosarcoma** is the most common primary malignant bone tumor and predominantly arises in the **metaphysis** of long bones. - It is characterized by the production of **osteoid** or immature bone by malignant tumor cells. *Ewing's sarcoma* - **Ewing's sarcoma** is a highly malignant small round blue cell tumor that typically arises in the **diaphysis** of long bones or in flat bones. - It is often associated with a characteristic **t(11;22) chromosomal translocation**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1205-1206.

Q: Paget's disease is also known as -

Osteitis deformans. ***Osteitis deformans*** - **Paget's disease of bone** is classically known by its historical name, **osteitis deformans**, reflecting the bone deformities observed [1]. - This chronic bone disorder is characterized by accelerated bone remodeling, resulting in enlarged and misshapen bones [1], [2]. *Osteochondritis* - This term refers to **inflammation of bone and cartilage**, often due to overuse, trauma, or ischemia. - It does not describe Paget's disease, which involves a specific disorganization of bone remodeling rather than inflammation of cartilage. *Osteitis fibrosa cystica* - This condition is a skeletal manifestation of **severe hyperparathyroidism**, characterized by bone resorption and replacement with fibrous tissue and cysts. - While it involves bone changes, its etiology and pathological process are distinct from Paget's disease. *Osteomalacia* - **Osteomalacia** is a metabolic bone disease characterized by **defective mineralization of bone osteoid** in adults, primarily due to vitamin D deficiency [3]. - It leads to soft and weak bones, which is different from the disordered but often dense bone formation seen in Paget's disease. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1191-1194. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 660-661. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 668-669.

Question 1

Which of the following is a differential of giant cell tumor?

Accepted Answer

Chondroblastoma

Answer

Osteogenic sarcoma

Answer

Ossifying fibroma

Answer

Non-ossifying fibroma

Question 2

All of the following are seen in osteopetrosis EXCEPT:

Accepted Answer

Decreased bone density

Answer

Osteomyelitis of the mandible

Answer

Pancytopenia

Answer

Compression of cranial nerve

Question 3

Which of the following can histologically mimic Giant cell tumor due to presence of osteoclast-like giant cells?

Accepted Answer

Osteosarcoma

Answer

Chondroblastoma

Answer

Ossifying fibroma

Answer

Non ossifying fibroma

Question 4

Which bone tumor involves the epiphysis?

Accepted Answer

Giant cell tumor

Answer

Osteosarcoma

Answer

Ewing's sarcoma

Answer

Multiple myeloma

Question 5

Ewing's tumour arises from –

Accepted Answer

Primitive neuroectodermal cells

Answer

Mesothelial cell

Answer

Squamous cell

Answer

Endothelial cell

Question 6

Premalignant bone lesion among the following is -

Accepted Answer

Pagets disease

Answer

Osteoid osteoma

Answer

Enchondroma

Answer

Osteochondroma

Question 7

Marble bone disease is

Accepted Answer

Osteopetrosis

Answer

Osteomyelitis

Answer

Osteogenesis imperfecta

Answer

Osteoporosis

Question 8

Effect of hypoparathyroidism on bones include -

Accepted Answer

None of the Above

Answer

Brown tumours

Answer

Subperiosteal Resorption of Bone

Answer

Multiple Cysts in Bone

Question 9

Which bone tumor occurs in the epiphysis?

Accepted Answer

Osteoclastoma

Answer

Chondro-myxoid fibroma

Answer

Osteosarcoma

Answer

Ewing's sarcoma

Question 10

Paget's disease is also known as -

Accepted Answer

Osteitis deformans

Answer

Osteochondritis

Answer

Osteitis fibrosa cystica

Answer

Osteomalacia

Bone and Soft Tissue Pathology — MCQs

Bone and Soft Tissue Pathology — MCQs

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