Bone and Soft Tissue Pathology Practice Questions

Q: Osteosclerotic metastasis is common in which cancer?

Prostate. **Explanation:** Bone metastases are broadly classified into **osteolytic** (bone-destroying) and **osteoblastic/osteosclerotic** (bone-forming). **1. Why Prostate Cancer is Correct:** Prostate carcinoma is the classic example of a malignancy that produces **osteoblastic (sclerotic)** lesions. This occurs because prostate cancer cells secrete factors like Bone Morphogenetic Proteins (BMPs) and Endothelin-1, which stimulate osteoblasts to lay down new, dense, but disorganized bone. On X-ray, these appear as radiopaque (white) spots. **2. Analysis of Incorrect Options:** * **Lungs:** Lung cancer typically produces **osteolytic** lesions. An exception is Small Cell Lung Cancer, which can sometimes be mixed, but it is not the primary answer for pure sclerosis. * **Malignant Melanoma:** This is a highly aggressive tumor that characteristically causes **osteolytic** destruction. * **Renal Cell Carcinoma (RCC):** RCC is famous for producing purely **osteolytic**, "blow-out" expansile lesions that are highly vascular. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common source of Osteoblastic Mets:** Prostate (Men), Breast (Women - though breast is often mixed). * **Most common source of Osteolytic Mets:** Lung, RCC, Thyroid, and Multiple Myeloma. * **Purely Lytic:** RCC and Multiple Myeloma (Note: Multiple Myeloma is **Cold** on Bone Scan). * **Route of Spread:** Most spinal metastases spread via the **Batson’s venous plexus** (a valveless system). * **Investigation of Choice:** **Bone Scan (Technetium-99m)** is the most sensitive screening tool for most mets, except for Multiple Myeloma where a Skeletal Survey (X-ray) is preferred.

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.

Question 1

A 50-year-old woman presents with lower back pain of 3 weeks in duration. Radiologic studies reveal several discrete lytic lesions in the lumbar back and pelvis. Laboratory studies show elevated serum levels of alkaline phosphatase. Serum calcium, serum protein, and peripheral blood smears are normal. Aspiration biopsy of a pelvic lesion shows keratin-positive cells. Which of the following is the most likely diagnosis?

Accepted Answer

Metastatic carcinoma

Answer

Chondrosarcoma

Answer

Osteochondroma

Answer

Osteosarcoma

Question 2

Tennis racquet cells are characteristic of which of the following tumors?

Accepted Answer

Rhabdomyosarcoma

Answer

Rhabdomyoma

Answer

Histiocytoma

Answer

Eosinophilic granuloma

Question 3

A 40-year-old woman has severe, disabling rheumatoid arthritis. Rheumatoid factor is positive. What would a biopsy of the synovium of her knee most likely reveal?

Accepted Answer

A proliferative synovitis with many lymphocytes, macrophages, and plasma cells

Answer

A nearly normal synovium with scattered inflammatory cells

Answer

A non-proliferative synovitis with abscess formation

Answer

A non-proliferative synovitis with many neutrophils

Question 4

The prognosis of rhabdomyosarcoma is likely to be poor if the site of the tumour is:

Accepted Answer

Extremity

Answer

Orbit

Answer

Paratesticular

Answer

Urinary bladder

Question 5

Which of the following is a complication of rheumatoid arthritis of the mandibular condyle?

Accepted Answer

Fibrous ankylosis

Answer

Subluxation

Answer

Dislocation

Answer

None of the above

Question 6

Osteosclerotic metastasis is common in which cancer?

Accepted Answer

Prostate

Answer

Lungs

Answer

Malignant melanoma

Answer

Renal cell carcinoma

Question 7

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 8

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 9

Which of the following is implicated in the pathogenesis of rheumatoid arthritis?

Accepted Answer

Autoimmunity

Answer

Defective cellular and humoral immunity

Answer

Chronic microbial infections

Answer

IgE mediated

Question 10

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

Bone and Soft Tissue Pathology — MCQs

Bone and Soft Tissue Pathology — MCQs

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