Bone and Soft Tissue Pathology — MCQs

A 75-year-old man complains of lower back pain for years. As part of an investigation for persistently elevated lymphocytosis, a right posterior iliac crest biopsy was performed. Hematopoiesis is normal, but the bone spicules are thickened with irregular cement lines forming a mosaic appearance with both increased osteoblastic and osteoclastic activity. Which of the following conditions is most likely to occur in conjunction with this disease process?

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

Question 91: Which of the following is NOT true regarding Gilbert syndrome?

A. It causes cirrhosis (Correct Answer)
B. It is inherited in an autosomal dominant pattern
C. Liver function tests are typically normal
D. Liver histology is typically normal

Explanation: **Explanation:** **Gilbert Syndrome** is a common, benign hereditary condition characterized by mild, unconjugated hyperbilirubinemia [1]. **1. Why Option A is the Correct Answer (The False Statement):** Gilbert syndrome is a **benign condition** and does **not** lead to progressive liver damage, fibrosis, or **cirrhosis**. The liver remains structurally and functionally intact despite the intermittent jaundice [1]. **2. Analysis of Other Options:** * **Option B (Inheritance):** While most commonly associated with an autosomal recessive mutation in the *UGT1A1* gene promoter (TATAA box), it is clinically often described as having an **autosomal dominant** pattern of inheritance with variable penetrance in many medical texts, making this statement generally accepted as true in the context of competitive exams [1]. * **Option C (Liver Function Tests):** Apart from isolated elevations in indirect (unconjugated) bilirubin, standard LFTs (ALT, AST, Alkaline Phosphatase, and Albumin) are **typically normal**. * **Option D (Liver Histology):** The architecture of the liver is preserved. On biopsy, the **liver histology is normal**, though occasionally a slight increase in lipofuscin pigment may be noted [1]. **NEET-PG High-Yield Pearls:** * **Defect:** Reduced activity (approx. 30% of normal) of the enzyme **UDP-glucuronosyltransferase (UGT1A1)** [1]. * **Triggers:** Jaundice is typically precipitated by **stress, fasting, strenuous exercise, or illness**. * **Diagnosis:** Suggested by a rise in bilirubin after a 48-hour fast (Fasting test). * **Treatment:** No treatment is required; reassurance is the mainstay of management. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Liver and Gallbladder, p. 860.

Question 92: Duchenne Muscular Dystrophy is a disease of which component?

A. Neuromuscular junction
B. Sarcolemmal proteins (Correct Answer)
C. Muscle contractile proteins
D. Disuse atrophy due to muscle weakness

Explanation: ### Explanation **Correct Option: B. Sarcolemmal proteins** Duchenne Muscular Dystrophy (DMD) is an X-linked recessive disorder caused by a mutation in the **DMD gene**, which encodes the protein **Dystrophin** [1]. Dystrophin is a critical component of the **Dystrophin-Glycoprotein Complex (DGC)**, which links the intracellular actin cytoskeleton to the extracellular matrix through the cell membrane (sarcolemma). The primary function of dystrophin is to provide mechanical stability to the **sarcolemmal membrane** during muscle contraction and relaxation. In DMD, the absence of dystrophin leads to membrane fragility, resulting in calcium influx, myofiber necrosis, and progressive replacement of muscle with fibrofatty tissue [1]. **Analysis of Incorrect Options:** * **A. Neuromuscular junction:** This is the site of pathology for diseases like **Myasthenia Gravis** (acetylcholine receptor antibodies) and **Lambert-Eaton Syndrome** (voltage-gated calcium channel antibodies). * **C. Muscle contractile proteins:** These include actin and myosin. While dystrophin interacts with actin, it is a structural/linking protein, not a contractile one. Mutations in contractile proteins are more commonly associated with certain cardiomyopathies. * **D. Disuse atrophy:** This refers to muscle wasting due to lack of physical activity or nerve injury (e.g., prolonged immobilization). DMD is a primary **myopathy**, not a secondary atrophy. **High-Yield Clinical Pearls for NEET-PG:** * **Genetics:** X-linked recessive; DMD gene is the largest known human gene (high spontaneous mutation rate) [1]. * **Clinical Signs:** **Gower’s sign** (using hands to "climb up" the legs to stand) and **Pseudohypertrophy of calves** (fatty replacement). * **Diagnosis:** Markedly elevated **Serum Creatine Kinase (CK)** levels; Muscle biopsy shows variation in fiber size and increased endomysial fibrosis [1]. * **Becker Muscular Dystrophy (BMD):** A milder form caused by *truncated* (rather than absent) dystrophin [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, pp. 1244-1245.

Question 93: MIC-2 is a marker for which of the following conditions?

A. Ewing sarcoma (Correct Answer)
B. Osteosarcoma
C. Dermatofibroma
D. Alveolar soft part sarcoma

Explanation: **Explanation:** **MIC-2 (CD99)** is a cell surface glycoprotein that is highly sensitive for the **Ewing Sarcoma/Primitive Neuroectodermal Tumor (PNET)** family of tumors. In Ewing sarcoma, CD99 shows a characteristic strong, diffuse, and continuous membranous staining pattern. While it is not entirely specific, it is the primary diagnostic marker used to differentiate Ewing sarcoma from other "small round blue cell tumors" of childhood. **Analysis of Options:** * **A. Ewing Sarcoma (Correct):** Characterized by the translocation **t(11;22)(q24;q12)** involving the *EWS-FLI1* gene. It presents with an "onion skin" periosteal reaction on X-ray. * **B. Osteosarcoma:** The primary marker is **SATB2**. It is characterized by the production of malignant osteoid by tumor cells. * **C. Dermatofibroma:** Typically positive for **Factor XIIIa**, while its counterpart, Dermatofibrosarcoma Protuberans (DFSP), is positive for CD34. * **D. Alveolar Soft Part Sarcoma:** Characterized by the **TFE3** protein expression (due to X;17 translocation) and PAS-positive, diastase-resistant rhomboid crystals. **High-Yield Clinical Pearls for NEET-PG:** * **Ewing Sarcoma Genetics:** 90% of cases involve **t(11;22)**. * **CD99 Specificity:** Although MIC-2 is the hallmark for Ewing, it can also be positive in Lymphoblastic Lymphoma and Synovial Sarcoma; hence, it must be interpreted alongside morphology. * **Small Round Blue Cell Tumors (SRBCT) Differential:** * Neuroblastoma (NSE+, Synaptophysin+, Homer-Wright rosettes) * Rhabdomyosarcoma (Desmin+, Myogenin+) [1] * Lymphoma (CD45/LCA+) * Ewing Sarcoma (CD99+, PAS+ due to glycogen) **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1224-1225.

Question 94: Which tumor shows a biphasic pattern on histology?

A. Rhabdomyosarcoma
B. Synovial sarcoma (Correct Answer)
C. Osteosarcoma
D. Neurofibroma

Explanation: **Explanation:** **Synovial Sarcoma** is the classic example of a **biphasic tumor** in soft tissue pathology [1]. The term "biphasic" refers to the presence of two distinct cell populations: 1. **Epithelial cells:** Cuboidal to columnar cells that often form gland-like structures or nests. 2. **Spindle cells:** Uniform, small cells arranged in dense, cellular fascicles. *Note: Some synovial sarcomas are "monophasic," consisting only of spindle cells, but the biphasic pattern is pathognomonic [1].* **Analysis of Incorrect Options:** * **A. Rhabdomyosarcoma:** Characterized by **rhabdomyoblasts** (eccentric nuclei and eosinophilic cytoplasm) and "tadpole" or "strap" cells. It does not show an epithelial component. * **C. Osteosarcoma:** Defined by the production of **osteoid** (unmineralized bone) by malignant mesenchymal cells. It is a monophasic mesenchymal tumor. * **D. Neurofibroma:** A benign nerve sheath tumor composed of a mixture of Schwann cells, fibroblasts, and perineural cells in a **myxoid stroma** (shredded-carrot appearance), lacking a biphasic epithelial-spindle arrangement. **High-Yield Clinical Pearls for NEET-PG:** * **Cytogenetics:** Synovial sarcoma is strongly associated with the **t(X;18) (p11;q11)** translocation, resulting in the **SS18-SSX** fusion gene [1]. * **Location:** Despite the name, it rarely arises from the intra-articular synovial membrane; it typically occurs in the deep soft tissues near large joints (especially the knee) in young adults [1]. * **IHC Markers:** Positive for **Cytokeratin (CK)** and **EMA** (in the epithelial component) and **TLE1** (highly sensitive and specific marker). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1225-1226.

Question 95: Multiple dentigerous cysts are found in which of the following conditions?

A. Gardner's syndrome
B. Gorlin-Goltz syndrome
C. Cleidocranial dysplasia (Correct Answer)
D. Down's syndrome

Explanation: **Explanation:** **Cleidocranial Dysplasia (CCD)** is the correct answer because it is characterized by a triad of clinical features: aplastic or hypoplastic clavicles, delayed closure of cranial sutures (fontanelles), and significant dental anomalies. The dental hallmark of CCD is the presence of **multiple supernumerary teeth** that fail to erupt. These impacted teeth often lead to the formation of **multiple dentigerous cysts** (follicular cysts) within the jaw. **Analysis of Incorrect Options:** * **Gardner’s Syndrome:** While this syndrome involves dental anomalies, it is specifically associated with **multiple osteomas** of the jaw, odontomas, and impacted teeth, rather than multiple dentigerous cysts. It is primarily known for intestinal polyposis. * **Gorlin-Goltz Syndrome (Nevoid Basal Cell Carcinoma Syndrome):** This is a classic "distractor." It is associated with **multiple Odontogenic Keratocysts (OKCs)**, not dentigerous cysts [1]. This is a high-yield distinction for exams. * **Down’s Syndrome:** Patients often exhibit delayed eruption, microdontia, and missing teeth (hypodontia), but multiple dentigerous cysts are not a characteristic feature. **High-Yield Clinical Pearls for NEET-PG:** * **Cleidocranial Dysplasia:** Caused by a mutation in the **RUNX2** gene. Look for the "ability to touch shoulders in the midline" in clinical vignettes. * **Dentigerous Cyst:** The most common developmental odontogenic cyst; it attaches to the **cementoenamel junction (CEJ)** and encloses the crown of an unerupted tooth. * **Differential for Multiple Jaw Cysts:** Always distinguish between OKCs (Gorlin-Goltz) and Dentigerous cysts (Cleidocranial dysplasia). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Skin, pp. 1157-1158.

Question 96: What is the characteristic translocation seen in Ewing's sarcoma?

A. t(2;8)
B. t(11;22) (Correct Answer)
C. t(x;18)
D. t(14;18)

Explanation: ### Explanation **Correct Option: B. t(11;22)** Ewing’s sarcoma is a highly aggressive, small round blue cell tumor of the bone and soft tissue. The hallmark of this condition is a specific chromosomal translocation, **t(11;22)(q24;q12)**, which is present in approximately 90-95% of cases. This translocation results in the fusion of the **EWS gene** (on chromosome 22) with the **FLI1 gene** (on chromosome 11), a member of the ETS family of transcription factors. The resulting **EWS-FLI1 fusion protein** acts as a potent oncogenic transcription factor that drives uncontrolled cell proliferation and survival. **Analysis of Incorrect Options:** * **A. t(2;8):** This is a variant translocation associated with **Burkitt Lymphoma** (involving c-MYC and the Ig kappa light chain). The classic translocation is t(8;14) [1]. * **C. t(x;18):** This is the characteristic translocation for **Synovial Sarcoma**, resulting in the *SYT-SSX* fusion gene [2]. * **D. t(14;18):** This is the hallmark of **Follicular Lymphoma**, leading to the overexpression of the *BCL-2* anti-apoptotic protein. **High-Yield Clinical Pearls for NEET-PG:** * **Radiology:** Classically presents with an **"Onion-skin"** periosteal reaction. * **Morphology:** Characterized by sheets of **small round blue cells**; PAS-positive (due to cytoplasmic glycogen) and **Homer-Wright rosettes** (seen in 25% of cases). * **Immunohistochemistry (IHC):** Strong membranous expression of **CD99 (MIC2)** is a highly sensitive marker. * **Demographics:** Most common in the second decade of life; typically affects the diaphysis of long bones (e.g., Femur). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 324-325. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1225-1226.

Question 97: Which of the following conditions exhibits a soap bubble appearance?

A. Ameloblastoma
B. Odontogenic keratocyst
C. Odontogenic myxoma
D. All of the above (Correct Answer)

Explanation: In oral pathology, the **"soap bubble" appearance** refers to a multilocular radiolucency where large, circular, and overlapping compartments are separated by thin bony septa. This appearance is a hallmark of several odontogenic lesions, making "All of the above" the correct choice. [1] ### **Detailed Explanation** 1. **Ameloblastoma:** This is the most common clinically significant odontogenic tumor. It typically presents as a painless, slow-growing expansion of the jaw. Radiographically, it classically shows a multilocular "soap bubble" or "honeycomb" appearance, often associated with an unerupted third molar and root resorption. [1] 2. **Odontogenic Myxoma:** Derived from odontogenic ectomesenchyme, this tumor is locally invasive. Its radiographic hallmark is a multilocular radiolucency with thin, straight, or "tennis racket" septa, which frequently mimics the soap bubble appearance of ameloblastoma. 3. **Odontogenic Keratocyst (OKC):** While many OKCs are unilocular, larger lesions often become multilocular. Due to their aggressive growth pattern and ability to expand the bone, they can present with a soap bubble appearance on a panoramic radiograph. [1] ### **High-Yield Clinical Pearls for NEET-PG** * **Differential Diagnosis for Soap Bubble Appearance (Mnemonic: MACHO):** * **M**yxoma (Odontogenic) * **A**meloblastoma * **C**entral Giant Cell Granuloma (CGCG) * **H**emangioma (Central) * **O**dontogenic Keratocyst (OKC) / **O**ne (Aneurysmal Bone Cyst) * **Ameloblastoma** is most common in the **molar-ramus area** of the mandible. [1] * **OKC** is associated with **Gorlin-Goltz Syndrome** (Nevoid Basal Cell Carcinoma Syndrome) and has a high recurrence rate due to "daughter cysts." * **Cherubism** also presents with bilateral multilocular radiolucencies in children, often described as "soap bubble" or "eyes turned toward heaven." **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, pp. 741-742.

Question 98: Which of the following is NOT a possible effect of a dentigerous cyst on surrounding tissue?

A. Resorption of cortex (Correct Answer)
B. Resorption of adjacent teeth
C. Displacement of the floor of the maxillary antrum
D. Expansion of the outer cortical boundary of the involved jaw

Explanation: ### Explanation A **dentigerous cyst** (follicular cyst) is the most common developmental odontogenic cyst, arising from the separation of the follicle from around the crown of an unerupted tooth. **Why Option A is the Correct Answer:** While dentigerous cysts are known for their slow, expansive growth, they typically cause **thinning and expansion** of the cortical plates rather than frank **resorption (destruction)** of the cortex. In pathology, "resorption" of the cortex usually implies an aggressive, infiltrative, or malignant process (like Squamous Cell Carcinoma or certain aggressive Ameloblastomas). A dentigerous cyst pushes the bone boundaries outward due to osmotic pressure, maintaining a thin shell of bone around it. **Analysis of Incorrect Options:** * **B. Resorption of adjacent teeth:** Although the cyst originates from one unerupted tooth (usually the mandibular 3rd molar), the pressure exerted by the expanding cystic fluid can lead to the root resorption of neighboring erupted teeth. * **C. Displacement of the floor of the maxillary antrum:** Large cysts in the maxilla frequently expand superiorly, displacing the floor of the maxillary sinus (antrum) as they grow. * **D. Expansion of the outer cortical boundary:** This is a hallmark radiographic feature. The cyst causes a painless, slow-growing bony expansion that "balloons" the cortex outward. **Clinical Pearls for NEET-PG:** * **Radiographic Appearance:** Well-circumscribed, unilocular radiolucency attached to the **cemento-enamel junction (CEJ)** of an unerupted tooth. * **Most Common Site:** Mandibular third molars, followed by maxillary canines. * **Histopathology:** Lined by thin, non-keratinized stratified squamous epithelium (2–3 layers thick). * **Potential Complication:** If left untreated, the lining can undergo neoplastic transformation into **Ameloblastoma**, Squamous Cell Carcinoma, or Mucoepidermoid Carcinoma.

Question 99: What is the most common tumor of the jaw?

A. Ameloblastoma (Correct Answer)
B. Osteogenic sarcoma
C. Fibrosarcoma
D. Squamous cell carcinoma

Explanation: **Explanation:** **Ameloblastoma** is the correct answer because it is the most common clinically significant odontogenic tumor [1]. It arises from the odontogenic epithelium (remnants of the dental lamina or enamel organ) [1]. While it is histologically benign, it is locally aggressive, characterized by a "soap-bubble" or "honeycomb" appearance on X-ray, and has a high recurrence rate if not widely excised. **Analysis of Incorrect Options:** * **B. Osteogenic Sarcoma:** While it is the most common primary malignant bone tumor overall, it is relatively rare in the jaw compared to odontogenic tumors like ameloblastoma. * **C. Fibrosarcoma:** This is a rare soft tissue or bone malignancy. It does not occur in the jaw with the same frequency as epithelial odontogenic tumors. * **D. Squamous Cell Carcinoma (SCC):** SCC is the most common **malignancy of the oral cavity** (mucosa), but it is not classified as a primary "tumor of the jaw" bone itself, unless it is a rare intraosseous variant or involves the jaw via secondary invasion. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Mandible (specifically the molar-ramus area). * **Radiology:** Classic **"Soap-bubble" appearance** (multilocular radiolucency). * **Histopathology:** Features "Stellate reticulum-like" cells and peripheral palisading of columnar cells with **reverse polarity** (Vickers-Gorlin criteria). * **Key Association:** Often associated with an unerupted third molar (dentigerous cyst). * **Note:** If the question asks for the most common *odontogenic tumor* overall (including hamartomas), some texts cite **Odontoma**; however, among true neoplasms, Ameloblastoma remains the standard answer for the jaw. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, pp. 741-742.

Question 100: A 75-year-old man complains of lower back pain for years. As part of an investigation for persistently elevated lymphocytosis, a right posterior iliac crest biopsy was performed. Hematopoiesis is normal, but the bone spicules are thickened with irregular cement lines forming a mosaic appearance with both increased osteoblastic and osteoclastic activity. Which of the following conditions is most likely to occur in conjunction with this disease process?

A. Dementia
B. Myelofibrosis
C. Hepatic cirrhosis
D. Congestive Cardiac Failure (Correct Answer)

Explanation: ### Explanation **Diagnosis: Paget Disease of Bone (Osteitis Deformans)** The clinical presentation of an elderly patient with thickened bone spicules, **irregular cement lines**, and a characteristic **"mosaic pattern"** (jigsaw-puzzle appearance) of lamellar bone is pathognomonic for **Paget Disease of Bone** [3]. This condition involves a three-stage process: an initial osteolytic phase, a mixed phase (increased osteoblastic and osteoclastic activity), and a final osteosclerotic phase [1]. **Why Congestive Cardiac Failure (CCF) is correct:** In the polyostotic (multiple bone) form of Paget disease, the intense remodeling and hypervascularity of the affected bone lead to the formation of numerous **arteriovenous (AV) shunts**. These shunts decrease peripheral vascular resistance, leading to a **high-output state**. Over time, this chronic volume overload results in **High-Output Heart Failure**, a classic systemic complication of extensive Paget disease [2]. **Why the other options are incorrect:** * **A. Dementia:** While Paget disease can cause hearing loss or cranial nerve palsies due to foraminal narrowing, it is not a primary cause of dementia [1]. * **B. Myelofibrosis:** Although Paget disease involves bone remodeling, it does not cause primary marrow fibrosis or extramedullary hematopoiesis. * **C. Hepatic cirrhosis:** There is no pathophysiological link between Paget disease and liver cirrhosis. **High-Yield Clinical Pearls for NEET-PG:** * **Biochemical Marker:** Characterized by **isolated elevation of Serum Alkaline Phosphatase (ALP)** with normal Calcium, Phosphate, and PTH levels. * **Most Common Site:** Pelvis, followed by the skull and femur [1]. * **Complications:** The most dreaded neoplastic complication is **Osteosarcoma** (occurs in <1% of cases, usually in elderly patients) [3]. * **Treatment:** Bisphosphonates (e.g., Zoledronic acid) are the mainstay of therapy to inhibit osteoclastic activity [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. 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. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 669-670.

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

Practice Questions

Joints and Rheumatologic Diseases

Practice Questions

Soft Tissue Tumors

Practice Questions

Muscular Dystrophies and Myopathies

Practice Questions

Diseases of Tendons and Fascia

Practice Questions

Pathology of Orthopedic Implants

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free