Bone and Soft Tissue Pathology — MCQs

Bone and Soft Tissue Pathology Indian Medical PG Practice Questions and MCQs

Question 281: Paget's disease is also known as -

A. Osteitis deformans (Correct Answer)
B. Osteochondritis
C. Osteitis fibrosa cystica
D. Osteomalacia

Explanation: ***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 282: Bone mass is reduced in all of the following conditions EXCEPT:

A. Osteoporosis
B. Osteopetrosis (Correct Answer)
C. Hyperparathyroidism
D. Osteomalacia

Explanation: **Osteopetrosis** - **Osteopetrosis**, also known as **marble bone disease**, is a rare genetic disorder characterized by **increased bone density** due to defective osteoclast function. - In this condition, osteoclasts are unable to resorb bone, leading to an excessive accumulation of bone tissue, resulting in **densified but brittle bones**. *Osteoporosis* - **Osteoporosis** is characterized by significantly **reduced bone mass** and microarchitectural deterioration of bone tissue [1]. - This leads to increased bone fragility and a higher risk of fractures, as the bone becomes porous and weak [2]. *Hyperparathyroidism* - **Hyperparathyroidism** causes **increased bone resorption** due to excessive parathyroid hormone (PTH) secretion. - PTH mobilizes calcium from the bones, leading to a **decrease in bone density** and potential bone cysts (**osteitis fibrosa cystica**) [3]. *Osteomalacia* - **Osteomalacia** is a condition where there is **defective mineralization of bone osteoid**, leading to softer bones [4]. - While the bone mass might appear structurally normal, the **mineral content is reduced**, making the bone weak and susceptible to bowing and fractures. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1189-1191. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 665-666. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1194. [4] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1194-1195.

Question 283: Which of the following terms is MOST appropriate for growth of bone?

A. Increase in size (Enlargement)
B. Hypertrophy
C. Apposition (Correct Answer)
D. Hyperplasia

Explanation: ***Apposition*** - **Appositional growth** refers to the increase in the **thickness** or diameter of a bone due to the addition of new bone matrix on the surface by **osteoblasts** [1]. - This process is crucial for the continuous remodeling and reshaping of bones throughout life [2]. *Increase in size (Enlargement)* - While bone *does* increase in size during growth, "enlargement" is a general term that doesn't specifically describe the cellular mechanism of how bone tissue itself grows. - It could refer to an increase in overall dimension without detailing the biological process. *Hypertrophy* - **Hypertrophy** is the increase in the **size of individual cells**, leading to an increase in the size of the tissue or organ [3]. - Bone growth primarily involves the deposition of new matrix and the proliferation of cells, not just the enlargement of existing bone cells. *Hyperplasia* - **Hyperplasia** is an increase in the number of cells in a tissue or organ [3]. - While cell proliferation (an increase in osteoblast numbers) is part of bone growth, the term "apposition" more accurately captures the process of adding new bone matrix to the surface, which is the primary mechanism for bone thickening and lengthening. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1182-1184. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 662-663. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 87-88.

Question 284: Ewing's sarcoma is characterized by:

A. Small round blue cell tumor with CD99 positivity (Correct Answer)
B. Osteoid formation by malignant cells
C. Cartilage matrix production
D. Giant cell proliferation

Explanation: ***Ewing's sarcoma is characterized by:*** - **Small round blue cell tumor** with characteristic **CD99 positivity** on immunohistochemistry. - Presence of **t(11;22) translocation**, which leads to the **EWS-FLI1 fusion protein**. *Osteoid formation by malignant cells* - This is a hallmark feature of **osteosarcoma**, where malignant osteoblasts directly produce **osteoid** [1]. - **Ewing's sarcoma** does not produce osteoid; it's a primitive neuroectodermal tumor. *Cartilage matrix production* - This is characteristic of **chondrosarcoma**, a malignant tumor of cartilage-forming cells [2]. - **Ewing's sarcoma** is a bone tumor of different cellular origin and does not produce cartilage. *Giant cell proliferation* - While giant cells can be present in some bone tumors, **prominent giant cell proliferation** is primarily seen in **giant cell tumors of bone**, which are typically benign but locally aggressive. - **Ewing's sarcoma** is a small round blue cell tumor and not characterized by abundant giant cells. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 673-674. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1204-1205.

Question 285: All are predisposing factors of Osteogenic sarcoma except

A. Radiation
B. Paget's disease of bone
C. Viral infection (Correct Answer)
D. Bone infection

Explanation: ***Viral infection*** - **Viral infections** are generally not considered a direct predisposing factor for osteogenic sarcoma (osteosarcoma). - While some viruses are linked to certain cancers, there's no strong established causal link between common viral infections and osteosarcoma development. *Radiation* - **Therapeutic radiation** exposure, particularly at high doses or in children, is a recognized risk factor for developing secondary osteosarcoma. - Radiation can induce DNA damage and mutations in bone cells, leading to malignant transformation years after exposure. *Pagets disease of bone* - **Paget's disease of bone** is a chronic bone disorder characterized by abnormal bone remodeling, and it significantly increases the risk of developing osteosarcoma, especially in older individuals [1]. - The rapid and disorganized bone turnover in Paget's disease [1] creates an environment prone to malignant change. *Bone infection* - **Chronic osteomyelitis** (bone infection) has been implicated as a predisposing factor for the development of secondary osteosarcoma, particularly in rare cases. - Chronic inflammation and tissue damage associated with long-standing bone infections may contribute to malignant transformation. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1191-1192.

Question 286: Most common benign tumor of bone:

A. Bone cyst
B. Osteochondroma (Correct Answer)
C. Osteoblastoma
D. Chordoma

Explanation: ***Osteochondroma*** - **Osteochondroma** is the **most common benign bone tumor**, accounting for approximately 35-40% of all benign bone tumors [2]. - It arises from the growth plate and is characterized by a cartilage cap covering a bony stalk, typically affecting the **metaphysis** of long bones [1], [2]. *Bone cyst* - **Unicameral bone cysts** (simple bone cysts) and aneurysmal bone cysts are common benign bone lesions, but they are not true tumors. - They are typically fluid-filled lesions that can weaken the bone, predisposing to **pathological fractures**. *Osteoblastoma* - **Osteoblastoma** is a rare benign bone tumor, much less common than osteochondroma [3]. - It is characterized by the production of **osteoid** and **woven bone** and often causes pain due to its richly innervated nature [3]. *Chordoma* - **Chordoma** is a rare, malignant bone tumor, not benign. - It arises from remnants of the **notochord** and typically occurs at the sacrococcygeal region, skull base, or vertebral column. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 672-673. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1202. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1200.

Question 287: Following are features of Paget's disease except -

A. Increased Urinary excretion of hydroxyproline
B. Deformity of bones
C. Lowered serum alkaline phosphatase (Correct Answer)
D. Secondary osteosarcoma

Explanation: ***Lowered serum alkaline phosphatase*** - Paget's disease is characterized by markedly **increased bone turnover**, involving both excessive bone resorption and disorganized bone formation. - This high bone formation activity leads to a significant **elevation in serum alkaline phosphatase (ALP)**, not a lowering, making this the incorrect feature [1]. *Increased Urinary excretion of hydroxyproline* - **Hydroxyproline** is a major component of **collagen**, and its urinary excretion is a marker of **collagen degradation** and bone resorption. - In Paget's disease, there is rapid and chaotic bone remodeling, leading to increased breakdown of collagen and thus **elevated urinary hydroxyproline**. *Deformity of bones* - The disorganized and rapid bone remodeling in Paget's disease results in structurally unsound and **enlarged, weakened bones**. - This often leads to **bone deformities**, bowing of long bones, and an increased risk of fractures due to the abnormal bone architecture [1], [2]. *Secondary osteosarcoma* - Paget's disease is a significant risk factor for the development of **secondary osteosarcoma**, a rare but aggressive bone cancer. - While most cases of Paget's disease do not progress to malignancy, the chronic and intense bone remodeling activity can predispose to malignant transformation, particularly in areas of long-standing 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.

Question 288: In pseudogout, material deposited is

A. Sodium oxalate
B. Monosodium urate
C. Calcium apatite
D. Calcium pyrophosphate (Correct Answer)

Explanation: ***Calcium pyrophosphate*** - Pseudogout, also known as **calcium pyrophosphate deposition (CPPD) disease**, is characterized by the deposition of **calcium pyrophosphate dihydrate (CPPD)** crystals in joints [1]. - These crystals can lead to acute inflammatory arthritis, mimicking gout, but are chemically distinct from urate crystals [1]. *Sodium oxalate* - **Sodium oxalate** crystals are not typically associated with joint deposition diseases like pseudogout or gout. - Oxalate is more commonly involved in the formation of **kidney stones (calcium oxalate stones)** and can cause systemic oxalosis in rare metabolic disorders. *Monosodium urate* - **Monosodium urate (MSU)** crystals are the hallmark of **gout**, a different form of inflammatory arthritis [2, 4]. - MSU crystal deposition occurs due to **hyperuricemia** and leads to recurrent episodes of acute arthritis, commonly affecting the **first metatarsophalangeal joint** [2, 4]. *Calcium apatite* - **Calcium apatite** crystals (basic calcium phosphate crystals) are associated with **hydroxyapatite deposition disease (HADD)**, which can cause periarticular inflammation and calcific tendinitis, especially in the shoulder. - While it also involves calcium, it is distinct from the **calcium pyrophosphate** crystals found in pseudogout. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 683-684. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1218-1220. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 682-683.

Question 289: Not true about osteoarthritis

A. Narrowing of joint space
B. Non-Inflammatory condition
C. Most common joint disease
D. DIP joint is spared (Correct Answer)

Explanation: ***DIP joint is spared*** - This statement is **incorrect** because **distal interphalangeal (DIP) joints** are commonly affected in osteoarthritis. - In fact, the presence of **Heberden's nodes** (at the DIP joints) and **Bouchard's nodes** (at the PIP joints) are characteristic features of osteoarthritis. *Narrowing of joint space* - **Joint space narrowing** is a hallmark radiological feature of osteoarthritis, resulting from **cartilage loss**. - This loss of articular cartilage leads to bones rubbing against each other, causing pain and further damage [2]. *Non-Inflammatory condition* - Osteoarthritis is primarily considered a **degenerative disease** rather than a pure inflammatory one, though inflammation can play a secondary role [1]. - The dominant pathology involves the breakdown of **articular cartilage** and changes in the bone below [1], [2]. *Most common joint disease* - Osteoarthritis is indeed the **most prevalent form of arthritis** and a leading cause of disability worldwide. - It affects millions of people, particularly with increasing age, due to wear and tear on the joints [2]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 675-676. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1210-1212.

Question 290: Osteogenic sarcoma arises from -

A. Epiphysis
B. Epiphyseal cortex
C. Metaphysis (Correct Answer)
D. Growth plate

Explanation: ***Metaphysis*** - **Osteogenic sarcoma (osteosarcoma)** most commonly originates in the **metaphysis** of long bones [2] due to the high rate of cell proliferation and bone turnover in this region during growth. - The **metaphysis** is the wide portion of a long bone between the epiphysis and the diaphysis, containing the growth plate historically. *Epiphysis* - The **epiphysis** is the end part of a long bone, initially separated from the main bone by cartilage but later fusing with it. - Tumors like **chondroblastoma** or **giant cell tumor (GCT)** are more commonly found in the epiphysis [1], not osteosarcoma. *Epiphyseal cortex* - The **epiphyseal cortex** refers to the outer layer of the epiphyseal bone. - While bone tumors can arise from cortical bone, the metaphysis as a whole is the primary site of origin for osteosarcoma. *Growth plate* - The **growth plate (physis)** is a cartilage plate responsible for longitudinal growth of bones. - While its rapid cellular activity is a factor in metaphyseal tumor formation, osteosarcoma arises from the bone tissue **adjacent to or within** the metaphysis, not directly from the cartilaginous growth plate itself. **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. 671-672.

Practice by Chapter

Bone Development and Growth

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Fracture Healing

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Osteomyelitis and Infectious Diseases

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Metabolic Bone Diseases

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Bone Tumors and Tumor-like Lesions

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Joints and Rheumatologic Diseases

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Soft Tissue Tumors

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Muscular Dystrophies and Myopathies

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Diseases of Tendons and Fascia

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Pathology of Orthopedic Implants

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