Bone and Soft Tissue Pathology Practice Questions

Q: The mucin clot test is used to detect which of the following?

Hyaluronate in synovial fluid. **Explanation:** The **Mucin Clot Test** (also known as the Ropes Test) is a biochemical assessment used to estimate the concentration and quality of **hyaluronate (hyaluronic acid)** in synovial fluid [1]. 1. **Why the correct answer is right:** Normal synovial fluid is rich in high-molecular-weight hyaluronate, which provides viscosity [1]. When glacial acetic acid (2–5%) is added to normal synovial fluid, the hyaluronate reacts with the acid to form a tight, ropy, and non-friable **mucin clot**. In inflammatory conditions (like Rheumatoid Arthritis or Septic Arthritis), the hyaluronate is degraded or diluted, resulting in a "poor" clot that is friable or flakes easily. 2. **Why the incorrect options are wrong:** * **A (Mucin in stool):** Stool analysis for mucus is typically done via gross inspection or microscopy (e.g., in dsyentery), not via the acid-precipitation mucin clot test. * **B & D (Protein in CSF/Pleural fluid):** Protein levels in these fluids are measured using quantitative assays like the Turbidimetric method or the Pandy test (specifically for globulins in CSF), but they do not form a "mucin clot" upon addition of acetic acid. 3. **High-Yield Clinical Pearls for NEET-PG:** * **Normal/Non-inflammatory fluid:** Forms a **Good** clot (tight, solid). * **Inflammatory/Infectious fluid:** Forms a **Poor** clot (friable, breaks into shreds). * **Key Ingredient:** Glacial acetic acid. * **Note:** This test is now largely historical and has been replaced by more accurate cell counts and crystal analysis, but it remains a frequent "classic" question in pathology exams. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1209-1210.

Q: The histopathology of osteopetrosis shows which of the following?

Endosteal bone formation and lack of normal bone resorption. **Explanation:** **Osteopetrosis** (also known as Marble Bone Disease or Albers-Sch$nberg disease) is a genetic disorder characterized by **defective osteoclast function or differentiation** [1]. 1. **Why Option A is correct:** The fundamental pathology is the **failure of normal bone resorption**. While osteoblasts continue to lay down bone (endosteal bone formation), the osteoclasts fail to remodel it. This results in the persistence of the primary spongiosa (calcified cartilage) within the marrow space [1]. The bone becomes symmetric, stony hard, and thickened, but paradoxically brittle. 2. **Why other options are incorrect:** * **Option B:** The pathology is primarily **endosteal** (internal remodeling) rather than periosteal (outer surface). * **Option C:** Osteopetrosis involves **increased calcification** (hypermineralization), not less. The bones are dense but lack the organized trabecular structure, making them **prone to fractures**, not resistant. * **Option D:** In most forms of osteopetrosis, osteoclasts are actually **increased in number** but are structurally dysfunctional (e.g., lacking a ruffled border) [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Erlenmeyer Flask Deformity:** Characteristic radiological finding where the ends of long bones (distal femur) are flared [1]. * **"Bone-within-bone" appearance:** Seen on X-ray due to failure of remodeling. * **Clinical Complications:** Pancytopenia (due to marrow space obliteration/myelophthisis), cranial nerve palsies (due to narrowing of neural foramina), and hepatosplenomegaly (extramedullary hematopoiesis) [1]. * **Genetic Marker:** Mutations in the **TCIRG1** gene (proton pump) or **CAII** (Carbonic Anhydrase II) are common causes. **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.

Question 1

Bone affection in scurvy is due to which of the following?

Accepted Answer

Defective osteoid matrix formation

Answer

Poor mineralization of the osteoid tissue

Answer

Defective calcification in osteoid

Answer

Increased degradation of osteoid tissue

Question 2

The SS18-SSX gene fusion is associated with which of the following entities?

Accepted Answer

Synovial sarcoma

Answer

Liposarcoma

Answer

Rhabdomyosarcoma

Answer

Ewing sarcoma

Question 3

Which histologic variant of rhabdomyosarcoma has the most favorable prognosis?

Accepted Answer

Embryonal

Answer

Alveolar

Answer

Mixed

Answer

Prognosis is equally poor in all variants

Question 4

The mucin clot test is used to detect which of the following?

Accepted Answer

Hyaluronate in synovial fluid

Answer

Mucin in stool

Answer

Protein in CSF

Answer

Protein in pleural fluid

Question 5

Elephantiasis neuromatosa is a feature of which of the following conditions?

Accepted Answer

Von Recklinghausen's disease

Answer

Neurilemmoma

Answer

Paraganglioma

Answer

Multiple endocrine neoplasia syndrome

Question 6

What is the most common cause of osteoblastic bone metastasis?

Accepted Answer

Prostatic carcinoma

Answer

Renal cell carcinoma

Answer

Wilm's tumor

Answer

Neuroblastoma

Question 7

Generalised hypercementosis is seen in which condition?

Accepted Answer

Paget's disease

Answer

Hypothyroidism

Answer

Trauma

Answer

All of the above

Question 8

Immature bony trabeculae are found in which of the following conditions?

Accepted Answer

Fibrous dysplasia

Answer

Paget's disease

Answer

Rickets

Answer

Cleidocranial Dysplasia

Question 9

The histopathology of osteopetrosis shows which of the following?

Accepted Answer

Endosteal bone formation and lack of normal bone resorption

Answer

Periosteal bone formation and lack of normal bone resorption

Answer

Presence of extra collagen fibers and less calcification resulting in resistance of bones to fracture

Answer

Presence of numerous osteoclasts and a few osteoclasts

Question 10

A 25-year-old male is diagnosed with osteosarcoma involving his right femur. Mutation of which of the following genes can be related to the development of osteosarcoma?

Accepted Answer

RB gene

Answer

APC gene

Answer

Bcl-2 gene

Answer

c-myc gene

Bone and Soft Tissue Pathology — MCQs

Bone and Soft Tissue Pathology — MCQs

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