Bone and Soft Tissue Pathology Practice Questions

Q: Which of the following statements about chronic osteomyelitis is false?

Involucrum is dead bone. ***Involucrum is dead bone*** - This statement is false because the **involucrum** is the layer of **new bone formation** that surrounds a segment of necrotic (dead) bone, known as the **sequestrum**, in chronic osteomyelitis [1]. - The involucrum represents the body's attempt to wall off the infection and dead bone, and thus, it is living, *reactive bone*, not dead bone [1]. *Reactive new bone formation* - This statement is true; **reactive new bone formation** occurs around infected or necrotic bone in chronic osteomyelitis, forming the **involucrum** [1]. - This process is a hallmark of the body's response to chronic infection and attempts to contain it. *Cloaca is an opening in involucrum* - This statement is true; a **cloaca** is a **fistulous tract** or opening in the **involucrum** that allows pus and necrotic debris from the infected area to drain to the skin surface. - This drainage is a common clinical sign of chronic osteomyelitis. *Sequestrum is hard and dense* - This statement is true; the **sequestrum** is a piece of **necrotic (dead) bone** that has become separated from living bone due to ischemia and infection [1]. - Due to the loss of blood supply and avascular necrosis, it appears **dense, hard, and radiodense** on imaging, representing devitalized bone tissue that is walled off from the body's immune response. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1197-1198.

Q: What are the common causes of vertebra plana?

All of the options. ***All of the options*** - **Vertebra plana** refers to the severe flattening of a vertebral body, often caused by a destructive lesion, and all listed options are known causes. [5] - While **eosinophilic granuloma** is a classic cause, **metastatic disease** and **tuberculosis** can also lead to significant vertebral collapse. [3], [5] *Eosinophilic granuloma* - This is a benign condition, a form of **Langerhans cell histiocytosis**, which commonly affects children and can cause vertebra plana. [1] - It results from proliferative lesions of **Langerhans cells** that infiltrate the bone, leading to its destruction and collapse. [1] *Metastatic disease* - **Malignant tumors** often spread to the spine, causing osteolytic lesions that weaken the vertebral body. [4], [5] - The destruction caused by metastatic deposits can lead to **vertebral collapse** and associated pain. [5] *Tuberculosis* - **Tuberculosis of the spine (Pott's disease)** is an infectious inflammatory condition that can severely damage vertebral bodies. [2], [3] - The granulomatous inflammation and caseous necrosis can erode the bone, leading to **vertebral collapse** and kyphosis. [2] **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 630. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1197-1198. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 669-670. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 724-725. [5] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 671-672.

Q: Brown tumors are seen in:

Hyperparathyroidism. ***Hypeparathyroidism*** - Brown tumors, also called osteitis fibrosa cystica, are **osteolytic lesions** associated specifically with **hyperparathyroidism** due to increased osteoclastic activity [1][2]. - Elevated levels of **parathyroid hormone (PTH)** lead to bone resorption, giving rise to the characteristic bone changes seen in this condition [1][2]. *Neurofibromatosis* - Neurofibromatosis primarily presents with **neurofibromas**, café-au-lait spots, and skin-related findings, not with brown tumors. - Bone manifestations include **scoliosis** or **plexiform neurofibromas**, but they do not typically lead to brown tumors. *Pigmented villonodular synovitis* - This is a **joint condition** featuring hyperplastic synovial tissue and local joint swelling, but it does not involve **bone changes** typical of brown tumors. - Characterized by **pigmented nodules** in the synovium, it doesn't cause osteolytic lesions seen in hyperparathyroidism. *Osteomalacia* - Osteomalacia is primarily due to **vitamin D deficiency**, leading to softening of the bones, not the formation of **brown tumors**. - It results in bone pain and weakness, with radiological changes such as **Looser's zones** rather than the well-defined lucencies associated with brown tumors. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1105-1106. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1194.

Q: In Articular cartilage, most active chondrocytes are seen in ?

Zone 2. ***Zone 2*** - This is the **transitional (or middle) zone**, where chondrocytes are numerous and more metabolically active, responsible for synthesizing major components of the extracellular matrix. - Chondrocytes here are typically **ovoid or round**, arranged somewhat randomly, and are involved in maintaining the cartilage structure. *Zone 1* - This is the **superficial (or tangential) zone**, where chondrocytes are **flattened** and oriented parallel to the articular surface. - Their primary role is to resist shear forces, and they are generally less metabolically active compared to those in the transitional zone. *Zone 3* - This is the **deep (or radial) zone**, characterized by **columnar arrangements** of chondrocytes. [1] - While these chondrocytes are metabolically active and synthesize matrix components, they are generally less active than those in the transitional zone and are more involved in resisting compressive forces. *Zone 4* - This is the **calcified zone**, directly adjacent to subchondral bone, where chondrocytes are **sparse** and often hypertrophic prior to eventual calcification. - This zone acts as an interface between cartilage and bone, and its chondrocytes have significantly reduced metabolic activity once calcification occurs. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1184.

Q: Which of the following is true about Giant cell tumor?

Epiphyseal origin. ***Epiphyseal origin*** - Giant cell tumors (GCTs) characteristically arise in the **epiphysis** or **metaphysis** of long bones, often extending into the subchondral bone [1]. - This distinguishes them from many other bone tumors that typically originate in the diaphysis or metaphysis. *Always benign* - While GCTs are predominantly **benign**, they have a significant potential for **local recurrence** and, in rare cases, can undergo **malignant transformation** or metastasize to the lungs. - Therefore, they are considered to have an **intermediate biological potential**, not strictly benign. *Seen in age less than 15 years* - GCTs are most commonly observed in **young adults**, typically between the ages of 20 and 40 years, after **skeletal maturity**. - They are exceedingly **rare** in individuals younger than 15 years, as the epiphyses are still open. *Usually presents as a lytic lesion without a sclerotic rim* - GCTs are indeed **lytic lesions**, appearing as areas of bone destruction without a significant periosteal reaction or sclerosis, giving them a **"soap-bubble" appearance**. - However, they often have a **thin sclerotic rim** in some parts of the lesion, especially at the margins, which helps differentiate them from more aggressive lesions [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.

Q: In which condition is pannus formation typically observed?

RA. ***RA*** - **Pannus** is a characteristic feature of **rheumatoid arthritis**, representing an aggressive, hyperplastic synovial tissue that invades and destroys cartilage and bone [1], [2]. - This destructive granulation tissue primarily consists of fibroblasts, macrophages, and inflammatory cells, contributing to joint erosion [1]. *Osteoarthritis (OA)* - While **osteophytes** (bone spurs) and **cartilage degradation** are hallmarks of OA, **pannus formation** is not seen. - OA involves breakdown of articular cartilage due to mechanical stress and biochemical changes, not synovial invasion. *Gout (Gouty Arthritis)* - Gout is characterized by the deposition of **monosodium urate crystals** in joints, leading to acute inflammation [4]. - The formation of **tophi** (urate crystal deposits) is typical, but not **pannus** [4]. *Psoriatic Arthritis (PsA)* - PsA can cause joint inflammation and erosion similar to RA but does not typically involve the extensive **pannus formation** characteristic of RA [3]. - Specific features of PsA include **enthesitis**, dactylitis and involvement of **DIP joints** [3]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 677-678. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1212. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1214-1215. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1218.

Q: Sequestrum is best defined as

A piece of dead bone surrounded by infected tissue. ***A piece of dead bone surrounded by infected tissue*** * A sequestrum is a fragment of **necrotic (dead) bone** that has become separated from the surrounding living bone in the context of **chronic osteomyelitis**. * The dead bone is typically surrounded by **infected granulation tissue and pus**, making it the classic definition taught in the context of bone infections. * The sequestrum acts as a **nidus for persistent infection**, as antibiotics cannot penetrate the avascular dead bone, making surgical removal often necessary. *A piece of dead bone without surrounding infection* * While a sequestrum is fundamentally dead bone, in clinical practice and standard teaching, it is **intrinsically associated with infection** in osteomyelitis. * The phrase "without surrounding infection" makes this option incorrect, as the classic sequestrum occurs in the **inflammatory milieu of chronic osteomyelitis**. *A piece of bone with compromised blood supply* * This describes **ischemic or avascular bone**, which is the **initial pathological event** that leads to bone death. * However, this is not the definition of sequestrum itself—the sequestrum is the **end result** (dead bone fragment) rather than bone with compromised vascularity. * A sequestrum has **no blood supply** (completely avascular), not merely compromised supply. *None of the options* * This is incorrect because the first option accurately captures the **standard definition of sequestrum** as taught in the context of chronic osteomyelitis in medical education.

Q: Ewing's sarcoma arises from which type of cells?

Primitive neuroectodermal cells. ***Primitive neuroectodermal cells*** - **Ewing's sarcoma** is a malignant small round blue cell tumor largely believed to arise from **primitive neuroectodermal cells**. - This cellular origin explains why it's often grouped under the term **PNET (Primitive Neuroectodermal Tumor)**. *G cells* - **G cells** are specialized **enteroendocrine cells** found in the stomach and duodenum that secrete **gastrin**. - They are involved in regulating gastric acid secretion and have no association with Ewing's sarcoma. *Totipotent cells* - **Totipotent cells** have the ability to differentiate into **any type of cell**, including embryonic and extraembryonic tissues. - While all cancers originate from cellular changes, Ewing's sarcoma originates from a more specific, committed cell lineage, not totipotent stem cells. *Neurons* - **Neurons** are the basic functional units of the nervous system, responsible for transmitting electrical and chemical signals. - While Ewing's sarcoma has neuroectodermal characteristics, it does not arise from fully differentiated neurons but rather from more **primitive precursors**.

Q: Glomus tumor is seen in -

Distal portion of digits. ***Distal portion of digits*** - **Glomus tumors** are most commonly found in the **distal extremities**, especially the **subungual region** (under the nail) of the fingers and toes. - This location accounts for over 75% of all glomus tumors, where they originate from specialized **neuromyoarterial glomus bodies** involved in thermoregulation. - The classic clinical triad includes **paroxysmal pain, point tenderness, and cold sensitivity**. *Rare locations such as retroperitoneum* - While glomus tumors can occur in unusual sites, the **retroperitoneum** is an exceptionally rare location for primary glomus tumors. - Extradigital glomus tumors account for approximately 25% of cases and can occur in various soft tissue sites. *Long bones and vertebrae* - Glomus tumors do not typically arise in **bone tissue** as they originate from glomus bodies in soft tissue. - Bone involvement, when present, is usually secondary due to pressure erosion from an adjacent soft tissue tumor rather than primary bone origin. *Proximal portion of digits (less common site)* - While glomus tumors can occasionally be found in less common digital locations, the **proximal portion of digits** is significantly less frequent than the distal, and particularly the subungual, region. - Their primary association remains with the **distal phalanx** and nail bed.

Q: Tadpole cells, comma-shaped cells on histopathology are seen in -

Rhabdomyosarcoma. ***Rhabdomyosarcoma*** - **Tadpole cells** and **comma-shaped cells** are characteristic histological features of **rhabdomyosarcoma**, representing primitive mesenchymal cells differentiating towards skeletal muscle. - These cells are often pleomorphic, with eccentric nuclei and fibrillar eosinophilic cytoplasm, giving them their distinctive shapes. *Trichoepithelioma* - This is a benign adnexal tumor of follicular differentiation, characterized by nests of **basaloid cells**, **horn cysts**, and rudimentary hair structures. - It does not typically feature tadpole or comma-shaped cells. *Histiocytoma* - A **benign fibrous histiocytoma** (dermatofibroma) is composed of fibroblasts and histiocytes forming storiform patterns. - **Malignant fibrous histiocytoma** (now often reclassified as undifferentiated pleomorphic sarcoma) features pleomorphic spindle cells and giant cells, but not specifically tadpole or comma-shaped cells. *Leiomyosarcoma* - This is a malignant tumor of **smooth muscle origin**, characterized by spindle cells with blunt-ended nuclei, arranged in fascicles. - It lacks the tadpole or comma-shaped cells seen in rhabdomyosarcoma.

Question 1

Which of the following statements about chronic osteomyelitis is false?

Accepted Answer

Involucrum is dead bone

Answer

Reactive new bone formation

Answer

Cloaca is an opening in involucrum

Answer

Sequestrum is hard and dense

Question 2

What are the common causes of vertebra plana?

Accepted Answer

All of the options

Answer

Eosinophilic granuloma

Answer

Metastatic disease

Answer

Tuberculosis

Question 3

Brown tumors are seen in:

Accepted Answer

Hyperparathyroidism

Answer

Pigmented villonodular synovitis

Answer

Osteomalacia

Answer

Neurofibromatosis

Question 4

In Articular cartilage, most active chondrocytes are seen in ?

Accepted Answer

Zone 2

Answer

Zone 1

Answer

Zone 4

Answer

Zone 3

Question 5

Which of the following is true about Giant cell tumor?

Accepted Answer

Epiphyseal origin

Answer

Seen in age less than 15 years

Answer

Usually presents as a lytic lesion without a sclerotic rim.

Answer

Always benign

Question 6

In which condition is pannus formation typically observed?

Accepted Answer

RA

Answer

Osteoarthritis (OA)

Answer

Gout (Gouty Arthritis)

Answer

Psoriatic Arthritis (PsA)

Question 7

Sequestrum is best defined as

Accepted Answer

A piece of dead bone surrounded by infected tissue

Answer

A piece of dead bone without surrounding infection

Answer

A piece of bone with compromised blood supply

Answer

None of the options

Question 8

Ewing's sarcoma arises from which type of cells?

Accepted Answer

Primitive neuroectodermal cells

Answer

G cells

Answer

Totipotent cells

Answer

Neurons

Question 9

Glomus tumor is seen in -

Accepted Answer

Distal portion of digits

Answer

Rare locations such as retroperitoneum

Answer

Long bones and vertebrae

Answer

Proximal portion of digits (less common site)

Question 10

Tadpole cells, comma-shaped cells on histopathology are seen in -

Accepted Answer

Rhabdomyosarcoma

Answer

Trichoepithelioma

Answer

Histiocytoma

Answer

Leiomyosarcoma

Bone and Soft Tissue Pathology — MCQs

Bone and Soft Tissue Pathology — MCQs

On this page

Practice by Chapter

Want unlimited practice?