Bone and Soft Tissue Pathology — MCQs

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

Question 321: In osteogenic sarcoma predominant histological finding is ?

A. Giant cells
B. Fibroblastic proliferation
C. Chondroblasts
D. Osteoid-forming tumor cells (Correct Answer)

Explanation: ***Osteoid forming tumor cells*** - The predominant histological finding in **osteogenic sarcoma** is the presence of **osteoid**, which indicates that the tumor cells are actively involved in bone formation [1]. - These **tumor cells** exhibit features of malignant **osteoblasts**, contributing to the characteristic appearance of the tumor [1]. *Giant cells* - While **giant cells** can be present in various bone lesions, they are typically associated with conditions like **giant cell tumor of bone**, not osteogenic sarcoma. - These cells are non-specific and do not reflect the **malignant osteoblastic nature** of osteogenic sarcoma. *Chondroblasts* - **Chondroblasts** are primarily involved in the formation of **cartilage**, and their presence would suggest conditions like **chondrosarcoma** rather than osteogenic sarcoma. - Osteogenic sarcoma is characterized by **osteoid formation**, not cartilage production. *Fibroblastic proliferation* - While **fibroblastic proliferation** can be seen in soft tissue tumors, it is not a hallmark finding in osteogenic sarcoma. - This histological feature does not indicate the presence of the **osteoid**, which is critical for diagnosing osteogenic sarcoma. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 673-674.

Question 322: A 30-year-old male presents with swelling around the knee joint. Histopathological examination reveals many giant cells interspersed with mononuclear cells. What is the most likely diagnosis?

A. Osteosarcoma
B. Ewing's sarcoma
C. Giant cell tumour (Correct Answer)
D. Chondrosarcoma

Explanation: ***Giant cell tumour*** - The presence of **giant cells** interspersed with **mononuclear cells** in the histopathological examination is characteristic of giant cell tumors [1], often found around the **knee joint** [1]. - Typically occurs in **young adults** and is associated with **subarticular bone lesions** that cause joint swelling [1]. *Osteosarcoma* - Generally presents with **extensive bone destruction** and **persistent pain**, along with a mass, not primarily giant cell formation. - Commonly involves individuals aged **10-20 years**, making it less likely in a 30-year-old male. *Ewing's sarcoma* - Characterized by **small round blue cells** on histology, often with **more aggressive behavior** and less prominent giant cells. - Typically affects the **pelvis** and **long bones**, rather than directly around the knee joint. *Chondrosarcoma* - Primarily characterized by **cartilage formation** with no prominent giant cells, often leading to a confusing diagnosis in imaging. - Usually occurs in **older adults** and does not typically present with predominant giant cells in histopathology. **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.

Question 323: A 20-year-old man presented with a complaint of a swelling of the wrist for the last two years. Histopathological examination showed spindle-shaped cells and Verocay bodies. What is the diagnosis?

A. Lipoma
B. Dermoid cyst
C. Neurofibroma
D. Schwannoma (Correct Answer)

Explanation: ***Schwannoma*** - Characterized by the presence of **spindle-shaped cells** and **Verocay bodies**, typical of schwannomas, which are tumors of peripheral nerve sheath origin [1,3]. - Commonly presents with **pain** and **local swelling** in affected areas, aligning with the patient's symptoms [2]. *Dermoid cyst* - Usually presents as a **cystic lesion** containing skin appendages but does not feature spindle-shaped cells. - Lacks the characteristic **Verocay bodies**, which help differentiate schwannomas [1]. *Lipoma* - Composed of **mature adipocytes**, presenting as soft, movable masses, but not associated with spindle-shaped cells. - Histopathological examination would not reveal **Verocay bodies**, making it distinct from schwannoma [1]. *Neurofibroma* - Typically associated with **plexiform growth patterns** and lacks the classic **Verocay bodies** seen in schwannomas [1]. - Often occurs in patients with **neurofibromatosis** and presents differently than the clinical scenario here [3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, p. 1250. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 727-728. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, pp. 1248-1249.

Question 324: Which statement is incorrect about the pathology of the bone tumor?

A. Tumor has distinct margin
B. Tumor arises from epiphyseal to metaphyseal region
C. Eccentric lesion
D. Chemotherapy is the treatment of choice for all bone tumors. (Correct Answer)

Explanation: ***Tumor has distinct margin*** - A **distinct margin** often indicates a benign tumor, while malignant tumors typically show **infiltrative margins**. - In bone tumors, particularly malignant ones, the lack of clear demarcation is a key pathological feature. *Chemotherapy is the treatment of choice* - While chemotherapy may be used for certain **malignant bone tumors**, it is not the first-line treatment for most bone tumors [1]. - The primary treatment is often **surgical excision**, especially for localized lesions [1]. *Tumor arise from epiphyseal to metaphyseal region* - While some tumors can originate in these areas, many actually arise from the **diaphyseal** region in bone tumors like osteosarcoma. - This option misrepresents the common locations where various tumors develop, as osteochondromas tend to develop near the epiphyses of limb bones [2]. *Eccentric lesion* - Many bone tumors do indeed present as **eccentric lesions**, especially benign ones like **osteochondromas**. - However, this feature does not apply universally, as some malignant tumors can also be **central or infiltrative** in nature. **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] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 672-673.

Question 325: A 40-year-old person presented with a swelling in the retroperitoneal area. A biopsy from the lesion is as shown below. Molecular analysis demonstrated t(12;16). What is the most probable diagnosis?

A. Myxoid liposarcoma (Correct Answer)
B. Benign lipoma
C. Synovial sarcoma
D. Pleomorphic sarcoma

Explanation: ***Myxoid liposarcoma*** - The presence of **t(12;16)** translocation is characteristic of myxoid liposarcoma, which is crucial for diagnosis [1]. - Typically presents as a **soft tissue mass**, often in the retroperitoneum, consistent with the patient's swelling [1]. *Pleomorphic sarcoma* - Does not specifically associate with **t(12;16)** translocation; it is more commonly associated with various genetic alterations [1]. - Typically presents as a **heterogeneous** and highly aggressive neoplasm, lacking the specific features noted in this case. *Synovial sarcoma* - More commonly associated with a **t(X;18)** translocation, not t(12;16), which rules it out in this context. - Usually presents around the **joints** and has a different histological pattern compared to liposarcoma. *Lipoma* - A benign tumor that typically does not involve significant genetic mutations like **t(12;16)** [1]. - Presents as a **soft, mobile mass** and does not generally occur in a retroperitoneal setting with this size [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. 1222-1223.

Question 326: Chordoma arises from:

A. Pharyngeal bursa
B. Notochord (Correct Answer)
C. Rathke’s pouch
D. Luschka's bursa

Explanation: ***Notochord*** - Chordoma is a **rare, slow-growing malignant bone tumor** that originates from **persistent notochordal remnants**. - The notochord is a flexible rod-like structure that serves as the primary axial support during embryonic development, eventually becoming the **nucleus pulposus** of the intervertebral discs. *Pharyngeal bursa* - The pharyngeal bursa is a normal anatomical variant, a small recess in the **posterior wall of the nasopharynx**. - It is not associated with the development of chordomas. *Rathke's pouch* - Rathke's pouch is an **ectodermal invagination** from the roof of the primitive mouth (stomodeum) that gives rise to the **anterior pituitary gland**. - Tumors arising from remnants of Rathke's pouch are typically **craniopharyngiomas**, not chordomas. *Luschka's bursa* - This term is sometimes used to refer to a **pharyngeal bursa**, as mentioned in the first incorrect option. - It is not the origin of chordomas.

Question 327: All of the following are true regarding Paget's Disease except which of the following?

A. It may progress to a secondary chondrosarcoma.
B. Pelvis is the most common site for Paget's disease.
C. High output cardiac failure is a rare complication.
D. Cranial nerve involvement is not typically seen. (Correct Answer)

Explanation: ***Correct Answer: Cranial nerve involvement is not typically seen.*** This statement is **FALSE**, making it the correct answer to this "except" question. - Cranial nerve involvement **IS** typically seen in Paget's disease affecting the skull [1] - **CN VIII (vestibulocochlear nerve)** is most commonly affected, leading to **sensorineural hearing loss** in up to 30-50% of patients with skull involvement - Other complications include **basilar invagination**, which can compress the brainstem and cranial nerves [1] - Visual disturbances from optic nerve compression can also occur **Why the other options are TRUE statements (and thus incorrect answers to this "except" question):** *Pelvis is the most common site for Paget's disease* - **TRUE** - The pelvis is affected in approximately **70% of Paget's disease cases**, making it the most common site [1] - Other commonly affected sites include: spine (~53%), skull (~42%), femur (~35%), and tibia [1] - The sacrum is the single most commonly affected bone *High output cardiac failure is a rare complication* - **TRUE** - While uncommon, high-output cardiac failure can occur in extensive Paget's disease [2] - The mechanism involves increased vascularity and **arteriovenous shunting** in affected bone - This increases cardiac output demand, which in severe polyostotic disease (affecting >35-40% of skeleton) can lead to cardiac decompensation - More likely in elderly patients with pre-existing cardiovascular disease *It may progress to a secondary chondrosarcoma* - **TRUE** - Malignant transformation occurs in <1% of Paget's disease cases - **Osteosarcoma** is the most common malignancy (~50% of transformations) - **Chondrosarcoma** and fibrosarcoma can also occur, though less commonly - Suspect malignant transformation if there is sudden increase in pain, rapid bone growth, or new soft tissue mass **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1192-1194. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 670-671.

Question 328: Which tumor is characterized by the presence of cells that resemble tennis rackets?

A. Seminoma
B. Vaginal adenocarcinoma
C. Langerhans cell histiocytosis (Correct Answer)
D. Sarcoma botyroides

Explanation: ***Langerhans cell histiocytosis*** - This condition is characterized by **Birbeck granules** within the Langerhans cells, which have a distinctive **tennis racket-like appearance** on electron microscopy. - The cells are also positive for **CD1a** and **S-100** immunohistochemical markers. *Sarcoma botyroides* - This is a subtype of **embryonal rhabdomyosarcoma** typically found in mucosal sites, presenting as a polypoid, grape-like mass. - Its histology shows small, undifferentiated cells with primitive skeletal muscle differentiation, but **not tennis racket-shaped cells**. *Vaginal adenocarcinoma* - This is a rare malignancy of the vagina, often associated with **diethylstilbestrol (DES) exposure** in utero, presenting as glands. - The cells show glandular differentiation and produce mucin, but **lack Birbeck granules**. *Seminoma* - This is a germ cell tumor of the testis characterized by large, uniform cells with clear cytoplasm and prominent nucleoli, divided into lobules by fibrous septa containing lymphocytes. - There are **no tennis racket-shaped cells** or Birbeck granules associated with seminoma.

Question 329: Which of the following statements about chronic osteomyelitis is false?

A. Reactive new bone formation
B. Cloaca is an opening in involucrum
C. Involucrum is dead bone (Correct Answer)
D. Sequestrum is hard and dense

Explanation: ***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.

Question 330: All are features of Paget's disease except which of the following?

A. Defect in osteoclasts
B. Affects only axial skeleton (Correct Answer)
C. Can lead to hearing loss
D. Can lead to bone cancer

Explanation: ***Affects only axial skeleton*** - This statement is **FALSE** and therefore the correct answer to this "EXCEPT" question. - Paget's disease **can affect any bone in the body**, including both axial skeleton (spine, skull, pelvis) and appendicular skeleton (femur, tibia, humerus) [1]. - Common sites include: **pelvis (70%), spine, skull, femur, and tibia** [1]. - While it frequently affects axial bones, it is **not exclusive** to them. *Defect in osteoclasts* - This is a TRUE feature of Paget's disease. - The disease is characterized by **abnormal, hyperactive osteoclasts** with increased number of nuclei (up to 100 vs normal 3-5). - These osteoclasts show **excessive bone resorption activity** followed by disorganized bone formation [1]. - The primary defect involves **increased osteoclast activity and sensitivity to RANKL**. *Can lead to hearing loss* - This is a TRUE feature of Paget's disease. - Skull involvement can lead to **compression of cranial nerve VIII** (vestibulocochlear nerve) [1]. - Enlargement and disorganization of temporal bone can cause **conductive or sensorineural hearing loss**. - Occurs in approximately 30-50% of patients with skull involvement. *Can lead to bone cancer* - This is a TRUE feature of Paget's disease. - **Osteosarcoma** develops in approximately **1%** of Paget's disease patients. - Risk is higher in patients with **polyostotic disease** and long-standing involvement. - This is a rare but serious complication with poor prognosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1192-1194.

Practice by Chapter

Bone Development and Growth

Practice Questions

Fracture Healing

Practice Questions

Osteomyelitis and Infectious Diseases

Practice Questions

Metabolic Bone Diseases

Practice Questions

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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