Bone and Soft Tissue Pathology Practice Questions

Q: Keratocyst has all of the following features except?

Low recurrence rate.. **Explanation:** The **Odontogenic Keratocyst (OKC)** is a unique and aggressive developmental cyst derived from the dental lamina. The correct answer is **Option C** because OKCs are notorious for their **high recurrence rate** (ranging from 25% to 60%), rather than a low one. This high recurrence is attributed to the presence of "daughter cysts" or "satellite cysts" in the fibrous wall and the thin, friable nature of the epithelial lining, which makes complete surgical removal difficult. **Analysis of Options:** * **Option A:** OKCs are significantly **more common in the mandible** (60-80% of cases), particularly in the posterior body and ramus. * **Option B:** While the cyst lumen typically contains "cheesy" parakeratin, it may also be filled with **thin, straw-colored fluid** (transudate) or a clear liquid with low protein content (<4g/dL), which helps differentiate it from other cysts. * **Option D:** **Expansion of bone** is a common clinical finding. While OKCs tend to grow in an anteroposterior direction within the medullary cavity initially, larger lesions eventually cause cortical expansion and thinning. **High-Yield Clinical Pearls for NEET-PG:** * **Histology:** Characterized by a uniform 6–8 cell layer thick lining of parakeratinized stratified squamous epithelium with a **palisaded basal layer** (often described as "tombstone" appearance). * **Syndromic Association:** Multiple OKCs are a hallmark of **Gorlin-Goltz Syndrome** (Nevoid Basal Cell Carcinoma Syndrome), associated with *PTCH* gene mutations [1]. * **Radiology:** Appears as a well-defined unilocular or multilocular radiolucency. * **Treatment:** Due to high recurrence, aggressive treatment like Enucleation with **Carnoy’s solution** or Marsupialization is often required. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Skin, pp. 1157-1158.

Q: A patient presents with morning stiffness and tests positive for anti-CCP antibodies. Which of the following histological features is most characteristic of the underlying disease?

Pannus formation and erosive joint damage. ***Pannus formation and erosive joint damage*** - **Anti-CCP antibodies** along with morning stiffness heavily suggest **Rheumatoid Arthritis (RA)**, whose defining feature is the proliferation of hyperplastic synovial tissue known as the **pannus** [1]. - The **pannus** invades and destroys the adjacent articular cartilage and subchondral bone, leading to characteristic joint **erosions** [1] and deformities [3]. *Non-caseating granulomas* - These histological findings are characteristic of systemic inflammatory conditions such as **Sarcoidosis** or certain types of inflammatory bowel disease like **Crohn's disease**. - Granulomas are distinct structures involving epithelioid macrophages and do not represent the primary destructive pathology in RA [1]. *Subepidermal blister with IgA deposits* - This pathology is specific to the skin disease **Dermatitis Herpetiformis**, often associated with Celiac disease. - It involves IgA deposition in the dermal papillae, which is completely irrelevant to the underlying joint pathology of RA. *Tophi with monosodium urate crystals* - These structures are the histological hallmarks of chronic **Gout**, resulting from the deposition of precipitated **monosodium urate** crystals usually surrounded by foreign-body giant cells [2]. - Gouty arthritis is clinically and immunologically distinct from RA, lacking anti-CCP antibody positivity. **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, pp. 1218-1220. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1214.

Q: Identify the tissue

Tonsil. ***Tonsil*** - The presence of **crypts** (invaginations of the surface epithelium) and a prominent **germinal center** within the lymphoid follicles are characteristic features of the tonsil [1]. - Tonsils are part of Waldeyer's ring and function in immune surveillance of the oral cavity and pharynx. *Lymph node* - Lymph nodes typically have a **capsule**, a distinct **cortex** and **medulla**, and afferent/efferent lymphatic vessels. - They lack the prominent crypts seen in tonsils. *Spleen* - The spleen is characterized by distinct **red pulp** (involved in filtering blood) and **white pulp** (lymphoid tissue). - It does not have crypts or a similar architectural organization to the tonsil. *Thymus* - The thymus is characterized by a **cortex** and **medulla**, with the presence of **Hassall's corpuscles** in the medulla [2]. - It is primarily involved in T-cell maturation and lacks the lymphoid follicles with germinal centers and crypts seen in tonsils. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 552-553. [2] 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. 634.

Q: A 16-year-old boy presents with pain and swelling around the knee for 3 months. X-ray of the affected region is shown below. What is the most likely diagnosis?

Osteosarcoma. ***Osteosarcoma*** - **Osteosarcoma** is the most common primary malignant bone tumor, typically affecting the **metaphysis** of long bones in adolescents and young adults [1,2]. - Radiographically, it often presents with a **sunburst appearance** or **Codman's triangle** due to periosteal reaction [1]. *Ewing's sarcoma* - **Ewing's sarcoma** is a malignant small round blue cell tumor, often presenting with an **onion-skin appearance** on X-ray due to lamellated periosteal reaction [3]. - It commonly affects the **diaphysis** of long bones and flat bones, and is associated with the **t(11;22) translocation** [3]. *Giant cell tumor* - **Giant cell tumor** is a benign but locally aggressive tumor, typically found in the **epiphysis** of long bones, especially around the knee [4]. - It is characterized by numerous **osteoclast-like giant cells** and has a characteristic **soap-bubble appearance** on imaging [4]. *Enchondroma* - **Enchondroma** is a benign cartilaginous tumor that arises within the **medullary cavity** of bone, most commonly in the small bones of the hands and feet [3]. - It is typically asymptomatic and discovered incidentally, often appearing as a **well-circumscribed lucent lesion** with calcifications [3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1200-1202. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 673-674. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 671-672. [4] 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: Bone biopsy specimen is shown below. Diagnosis is:

Paget's disease. ***Paget's disease*** - The image shows a **mosaic pattern of woven and lamellar bone**, with prominent **cement lines** (dark wavy lines). This disorganized bone remodeling is characteristic of Paget's disease. - Paget's disease involves excessive and disorganized bone turnover, leading to structurally abnormal and weakened bone. *Osteomalacia* - Characterized by **deficient mineralization of osteoid**, leading to accumulation of unmineralized matrix. - Histologically, this would present as wide, unmineralized osteoid seams, which are not seen in the image. *Osteoporosis* - Defined by a **reduction in bone mass** and microarchitectural deterioration, leading to increased fracture risk. - Histologically, osteoporosis would show **thinner trabeculae** and **larger marrow spaces**, but the bone itself would be normally mineralized, lacking the disorganized mosaic pattern. *Osteosclerosis* - Refers to an **increase in bone density**, often due to increased bone formation or decreased bone resorption. - While Paget's disease can lead to increased bone density in affected areas, osteosclerosis as a primary diagnosis would typically involve uniformly dense, often thickened bone without the classic mosaic pattern seen here.

Q: The most common site for osteosarcoma is:

Distal femur. ***Distal femur*** - The **distal femur** is the most frequent site of involvement for **osteosarcoma**, accounting for approximately 40% of all cases [1]. - This region, along with the proximal tibia and proximal humerus, constitutes the most common locations for this primary malignant bone tumor [1]. *Proximal humerus* - While the **proximal humerus** is a common site for osteosarcoma, it is less frequent than the distal femur [1]. - It ranks third in incidence after the distal femur and proximal tibia [1]. *Proximal femur* - The **proximal femur** can be affected by osteosarcoma, but it is a relatively less common site compared to the distal femur. - Osteosarcomas tend to occur around the **growth plates** of long bones [1]. *Distal humerus* - The **distal humerus** is an uncommon site for the development of osteosarcoma. - It is much less frequently involved than the other major long bone metaphyses. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1200-1202.

Question 1

Keratocyst has all of the following features except?

Accepted Answer

Low recurrence rate.

Answer

It is more common in the mandible.

Answer

May be filled with thin, straw-colored fluid.

Answer

Expansion of bone is clinically seen.

Question 2

Which of the following is characteristic of Osteogenesis imperfecta?

Accepted Answer

It manifests with blue sclera, which are pathognomonic of this disease.

Answer

It is a sex-linked disorder of bones that develop in cartilage.

Answer

It may be associated with deafness.

Answer

It has associations with amelogenesis imperfecta.

Question 3

Which of the following has the strongest association with osteosarcoma?

Accepted Answer

Retinoblastoma

Answer

Wilms tumor

Answer

Rhabdomyosarcoma

Answer

Ewing's tumor

Question 4

An 8-year-old boy presents with progressive muscle weakness and walking difficulties. On examination, pseudohypertrophy of calf muscles was noted. Which of the following is true regarding this condition?

Accepted Answer

Absent dystrophin

Answer

Defective fibrillin

Answer

Abnormal collagen

Answer

Expansions of CTG triplet repeats

Question 5

A patient presents with morning stiffness and tests positive for anti-CCP antibodies. Which of the following histological features is most characteristic of the underlying disease?

Accepted Answer

Pannus formation and erosive joint damage

Answer

Subepidermal blister with IgA deposits

Answer

Tophi with monosodium urate crystals

Answer

Non-caseating granulomas

Question 6

Identify the tissue

Accepted Answer

Tonsil

Answer

Lymph node

Answer

Spleen

Answer

Thymus

Question 7

A 16-year-old boy presents with pain and swelling around the knee for 3 months. X-ray of the affected region is shown below. What is the most likely diagnosis?

Accepted Answer

Osteosarcoma

Answer

Ewing's sarcoma

Answer

Giant cell tumor

Answer

Enchondroma

Question 8

Bone biopsy specimen is shown below. Diagnosis is:

Accepted Answer

Paget's disease

Answer

Osteomalacia

Answer

Osteoporosis

Answer

Osteosclerosis

Question 9

The most common site for osteosarcoma is:

Accepted Answer

Distal femur

Answer

Proximal humerus

Answer

Proximal femur

Answer

Distal humerus

Question 10

A 40-year-old female presents with an irregular 5 × 6 cm mass in the right breast. Histopathological examination reveals the image shown. What is the most likely diagnosis?

Accepted Answer

Phyllodes tumor

Answer

Fibroadenoma

Answer

Invasive ductal carcinoma

Answer

Intraductal papilloma

Bone and Soft Tissue Pathology — MCQs

Bone and Soft Tissue Pathology — MCQs

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