Bone and Soft Tissue Pathology Practice Questions

Q: What is the most common developmental cyst of the jaws?

Dentigerous cyst. ### Explanation **Correct Answer: D. Dentigerous cyst** **Medical Concept:** A **dentigerous cyst** (also known as a follicular cyst) is the most common **developmental** odontogenic cyst. It originates from the separation of the follicle from around the crown of an **unerupted tooth**. It is characteristically attached to the cemento-enamel junction (CEJ). Pathologically, it is lined by thin, non-keratinized stratified squamous epithelium and is most frequently associated with impacted mandibular third molars. **Analysis of Incorrect Options:** * **A. Periapical cyst (Radicular cyst):** While this is the most common cyst of the jaws overall, it is **inflammatory** in origin (usually due to dental caries), not developmental [1]. * **B. Eruption cyst:** This is essentially a soft-tissue analogue of the dentigerous cyst that occurs in the gingiva during tooth eruption. While developmental, it is much less common than the dentigerous cyst. * **C. Calcifying odontogenic cyst (Gorlin cyst):** This is a rare developmental lesion characterized by "ghost cells" and focal calcifications. It represents only about 1% of all odontogenic cysts. **High-Yield NEET-PG Pearls:** * **Radiological Appearance:** Presents as a well-defined, unilocular radiolucency surrounding the crown of an unerupted tooth. * **Most Common Site:** Mandibular 3rd molars, followed by Maxillary canines. * **Potential Complications:** If left untreated, it can lead to the development of an Ameloblastoma, Squamous cell carcinoma, or Mucoepidermoid carcinoma. * **Key Distinction:** Always distinguish between **Inflammatory** (Radicular) vs. **Developmental** (Dentigerous) when reading the question stem [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, p. 741.

Q: A specimen shows a stalk-like resection of a pedunculated bony swelling. What is the most likely diagnosis?

Osteochondroma. ### Explanation **1. Why Osteochondroma is Correct:** Osteochondroma (Exostosis) is the most common benign bone tumor. It is characterized by a bony outgrowth covered by a cartilage cap. Morphologically, it presents in two forms: **pedunculated** (attached by a stalk) or **sessile** (broad-based). The presence of a "stalk-like" resection is pathognomonic for the pedunculated variety. A key diagnostic feature is that the cortex and the medullary cavity of the tumor are continuous with those of the host bone. **2. Why the Other Options are Incorrect:** * **Chondroma:** These are benign tumors of hyaline cartilage. **Enchondromas** occur within the medullary cavity (especially in short tubular bones of hands/feet), while **juxtacortical chondromas** occur on the surface but do not typically form a pedunculated bony stalk. * **Osteoid Osteoma:** This is a small, painful lesion characterized by a **nidus** (less than 2 cm) surrounded by a zone of reactive bone sclerosis. It does not present as a large pedunculated outgrowth. * **Osteoclastoma (Giant Cell Tumor):** This is an aggressive, **epiphyseal** lesion. Radiologically, it shows a "soap bubble" appearance and is characterized by bone destruction rather than a stalk-like bony protrusion. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Metaphysis of long bones (especially around the knee). * **Direction of growth:** It always grows **away from the joint** (towards the diaphysis). * **Genetics:** Associated with mutations in **EXT1 and EXT2** genes. * **Malignant Transformation:** Suggested if the cartilage cap thickness exceeds **2 cm** in adults (transforms into Chondrosarcoma). * **Multiple Hereditary Exostoses (Diaphyseal Aclasis):** An autosomal dominant condition featuring multiple osteochondromas.

Q: Widening of the periodontal ligament is a characteristic radiographic finding in which of the following conditions?

Osteosarcoma. **Explanation:** **Osteosarcoma** is the most common primary malignant tumor of the bone [1]. When it involves the jaw (gnathic osteosarcoma), a classic early radiographic sign is the **symmetric widening of the periodontal ligament (PDL) space**. This occurs because the malignant osteoblasts infiltrate the PDL space and cause the displacement of the tooth or resorption of the alveolar bone before significant bone destruction is visible elsewhere. This is often described as a "Garrington’s sign" and is a high-yield diagnostic clue for early-stage malignancy. **Analysis of Incorrect Options:** * **Hypercementosis:** Characterized by the excessive deposition of secondary cementum on the root surface. Radiographically, this appears as a bulbous enlargement of the root, but the PDL space remains **intact and follows the new contour** of the root rather than widening. * **Hypofunction of teeth:** When a tooth is not in function (e.g., loss of an opposing tooth), the PDL space actually **narrows** due to the lack of mechanical stimulation and atrophy of the principal fibers. * **Paget’s Disease:** While it affects the jaw, its classic radiographic features include a "cotton-wool" appearance of the bone and **loss of the lamina dura**, rather than isolated PDL widening. **NEET-PG High-Yield Pearls:** * **Sunburst Appearance:** The classic radiographic sign of osteosarcoma caused by periosteal reaction (Codman’s triangle is also seen [1]). * **Gnathic Osteosarcoma:** Occurs a decade later (3rd–4th decade) than long bone osteosarcoma and has a lower incidence of metastasis. * **Alkaline Phosphatase:** Often elevated in osteosarcoma, reflecting increased osteoblastic activity. **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.

Q: Giant cells are seen in which of the following conditions?

Osteoclastoma. **Explanation:** The presence of multinucleated giant cells is a hallmark of several bone lesions, but they are the defining characteristic of **Osteoclastoma (Giant Cell Tumor of Bone)**. 1. **Why Osteoclastoma is correct:** In this tumor, the "giant cells" are osteoclast-like cells distributed uniformly throughout a background of mononuclear stromal cells. It is important to note that the mononuclear stromal cells are the actual neoplastic component, while the giant cells are reactive. 2. **Analysis of Incorrect Options:** * **Chondroblastoma:** While it *can* contain giant cells, its hallmark is the "chicken-wire" calcification and chondroblasts. It is an epiphyseal tumor in young patients. * **Chordoma:** This tumor is characterized by **Physaliphorous cells** (large, vacuolated cells) and arises from remnants of the notochord, typically in the sacrum or clivus. * **Osteitis Fibrosa Cystica:** This is a metabolic bone disease (Hyperparathyroidism) that features "Brown Tumors." While these contain giant cells, the primary pathology is bone resorption and fibrous replacement due to PTH excess, not a primary bone neoplasm. **NEET-PG High-Yield Pearls:** * **Osteoclastoma Location:** Epiphyseal, commonly around the knee (distal femur/proximal tibia). * **Radiology:** Characterized by a "Soap-bubble appearance" and an eccentric location. * **Age Group:** Typically occurs in skeletally mature adults (20–40 years). * **Differential Diagnosis for Giant Cells:** Remember the mnemonic **"C-G-O-B"** (Chondroblastoma, Giant Cell Tumor, Osteoblastoma, Brown Tumor/Aneurysmal Bone Cyst). However, Osteoclastoma is the classic "Giant Cell Tumor."

Question 1

Arachnodactyly (spider fingers) is seen in which of the following conditions?

Accepted Answer

Marfan's syndrome

Answer

Down's syndrome

Answer

Turner's syndrome

Answer

All of the above

Question 2

What is the most common developmental cyst of the jaws?

Accepted Answer

Dentigerous cyst

Answer

Periapical cyst

Answer

Eruption cyst

Answer

Calcifying odontogenic cyst

Question 3

Secondary osteosarcoma is associated with which of the following conditions?

Accepted Answer

Paget's disease

Answer

Osteogenesis imperfecta

Answer

Melorheostosis

Answer

Ankylosing spondylitis

Question 4

A 37-year-old female presents with a contracture of the third digit of her left hand, impairing full extension. The condition has progressed over the last 6 months. Palpable beneath the skin of the left palm is a firm, hard, cord-like area measuring 1x3 cm. Histologically, what is this mass most likely composed of?

Accepted Answer

Malignant cells

Answer

Calcification

Answer

Caseous Material

Answer

Fibroblasts

Question 5

A specimen shows a stalk-like resection of a pedunculated bony swelling. What is the most likely diagnosis?

Accepted Answer

Osteochondroma

Answer

Chondroma

Answer

Osteoid osteoma

Answer

Osteoclastoma

Question 6

A 53-year-old man presents with a slowly enlarging mass over the olecranon process of his elbow. The mass is excised and found to have a chalky white consistency. Microscopically, the mass is composed of elongated, needle-shaped crystals that are negatively birefringent under polarized light. A granulomatous inflammatory infiltrate surrounds the crystals. Which of the following statements concerning this condition is NOT true?

Accepted Answer

Most patients with hyperuricemia will develop this condition.

Answer

The first metatarsophalangeal joint is typically involved.

Answer

The characteristic crystals can also be observed in synovial fluid.

Answer

This lesion has the potential to erode bone and cartilage.

Question 7

Widening of the periodontal ligament is a characteristic radiographic finding in which of the following conditions?

Accepted Answer

Osteosarcoma

Answer

Hypercementosis

Answer

Hypofunction of teeth

Answer

Paget's disease of bone

Question 8

What are the histological features of unicameral bone cysts?

Accepted Answer

Single cavity with connective tissue lining

Answer

Blood-filled cystic spaces

Answer

Endothelial cell lining

Answer

Fibrous tissue with cystic spaces

Question 9

What condition is characterized by the pathognomonic lesion known as a tophus?

Accepted Answer

Gout

Answer

Multiple myeloma

Answer

Cystinosis

Answer

Eale's disease

Question 10

Giant cells are seen in which of the following conditions?

Accepted Answer

Osteoclastoma

Answer

Chondroblastoma

Answer

Chordoma

Answer

Osteitis fibrosa cystica

Bone and Soft Tissue Pathology — MCQs

Bone and Soft Tissue Pathology — MCQs

On this page

Practice by Chapter

Want unlimited practice?