Bone and Soft Tissue Pathology Practice Questions

Q: Floating teeth syndrome is seen in which of the following conditions?

All of the above.. **Explanation:** The "Floating Teeth" appearance is a classic radiological sign where teeth appear to be suspended in mid-air due to the extensive destruction of the supporting alveolar bone. This occurs when pathological processes cause severe osteolysis of the mandible or maxilla without affecting the teeth themselves. **Breakdown of Options:** * **Langerhans Cell Histiocytosis (LCH):** Both **Eosinophilic Granuloma** (localized form) and **Hand-Schüller-Christian Disease** (multifocal chronic form) are subtypes of LCH [1]. In these conditions, the proliferation of Langerhans cells leads to punched-out lytic lesions in the jaw. As the alveolar bone is destroyed, the teeth lose their bony support, creating the "floating" appearance. * **Cherubism:** This is an autosomal dominant fibro-osseous condition characterized by symmetrical, multilocular cystic expansion of the jaws. The replacement of normal bone with fibrous tissue leads to displacement of teeth and loss of alveolar support, which can also result in a floating teeth appearance. **Clinical Pearls for NEET-PG:** 1. **Differential Diagnosis for Floating Teeth:** Apart from the options mentioned, consider **Multiple Myeloma**, **Burkitt Lymphoma**, and **Aggressive Periodontitis** (Papillon-Lefèvre syndrome). 2. **Hand-Schüller-Christian triad:** Includes (1) Calvarial bone defects, (2) Exophthalmos, and (3) Diabetes insipidus. 3. **LCH Markers:** High-yield immunohistochemistry markers include **CD1a, S100, and CD207 (Langerin)** [1]. Electron microscopy shows characteristic **Birbeck granules** (tennis-racket shape) [1]. 4. **Cherubism:** Associated with mutations in the **SH3BP2 gene**; typically presents in early childhood with "eyes turned toward heaven" appearance. **References:** [1] 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, pp. 629-630.

Q: A cyst is found in place of a tooth. What is the likely diagnosis?

Primordial cyst. ### Explanation The key to this question lies in the origin of the cyst relative to the tooth development process. **1. Why Primordial Cyst is Correct:** A **Primordial cyst** (now often classified under Odontogenic Keratocysts or OKCs) develops **in place of a tooth**. It arises from the degeneration of the enamel organ *before* any mineralized tooth structure has formed [1]. Consequently, the patient will have a missing tooth in the dental arch (most commonly the mandibular third molar), and the cyst occupies that specific space. **2. Why Other Options are Incorrect:** * **Dentigerous Cyst:** This is the most common odontogenic cyst [1]. It forms **around the crown** of an *uninterrupted* or impacted tooth (usually the third molar). Unlike the primordial cyst, the tooth is present, but it is trapped within the cyst. * **Eruption Cyst:** This is essentially a dentigerous cyst that occurs in the soft tissue overlying a **breaking/erupting tooth**. It appears as a bluish, fluid-filled swelling on the alveolar ridge; the tooth is present and attempting to emerge. **3. NEET-PG High-Yield Pearls:** * **Odontogenic Keratocyst (OKC):** Most primordial cysts are histologically OKCs [1]. Remember the "Satellite cysts" and high recurrence rate. * **Gorlin-Goltz Syndrome:** Multiple OKCs are a hallmark of this syndrome (associated with PTCH gene mutation, basal cell carcinomas, and bifid ribs). * **Radiological Sign:** Dentigerous cysts typically show a well-circumscribed lucency attached to the **cementoenamel junction (CEJ)**. * **Radicular Cyst:** The most common inflammatory cyst, found at the **apex** of a non-vital (carious) tooth [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Head and Neck, p. 741.

Q: Which of the following are characteristic histological features of a unicameral bone cyst?

Blood-filled cavities. **Explanation:** A **Unicameral Bone Cyst (UBC)**, also known as a Simple Bone Cyst, is a common benign, fluid-filled cavity. However, the histological hallmark that distinguishes it—especially when fractured—is the presence of **blood-filled spaces** or a serosanguinous fluid within a thin fibrous wall. * **Why Option A is Correct:** While a classic "simple" cyst contains clear yellow fluid, most specimens seen pathologically are associated with pathological fractures. This leads to hemorrhage, resulting in **blood-filled cavities** and the formation of a "cementum-like" fibro-osseous matrix (Riedel’s layer) within the cyst wall. * **Why Option B is Incorrect:** UBCs are "pseudocysts." They lack a true **endothelial or epithelial lining**. The wall is composed of thin vascular connective tissue. * **Why Option C is Incorrect:** While occasional multinucleated giant cells can be seen if a fracture has occurred (as part of the reactive process), they are not a primary characteristic feature. They are more diagnostic of **Aneurysmal Bone Cysts (ABC)** or Giant Cell Tumors. * **Why Option D is Incorrect:** UBCs are osteolytic lesions that cause thinning of the cortex; they do not characteristically show active new bone formation unless a fracture is healing. **High-Yield Clinical Pearls for NEET-PG:** * **Location:** Most common in the **proximal humerus** and **proximal femur** (metaphysis). * **Radiology:** Shows a well-demarcated radiolucent lesion. The **"Fallen Leaf Sign"** (a fractured cortical fragment settling at the bottom of the fluid-filled cyst) is pathognomonic. * **Age:** Typically occurs in children and adolescents (first two decades). * **Management:** Observation or steroid injection; surgery is indicated if there is a high risk of fracture.

Question 1

Floating teeth syndrome is seen in which of the following conditions?

Accepted Answer

All of the above.

Answer

Cherubism.

Answer

Eosinophilic granuloma.

Answer

Hand-Schuller-Christian disease.

Question 2

Which malignancy is characterized by large intracytoplasmic glycogen storage?

Accepted Answer

Ewing's sarcoma

Answer

Osteosarcoma

Answer

Mesenchymal chondrosarcoma

Answer

Leiomyosarcoma

Question 3

Which of the following is NOT a component of Naxos syndrome?

Accepted Answer

Lipomatous skin

Answer

Wooly hair

Answer

Hyperkeratosis of palms

Answer

Arrhythmogenic right ventricular hypertrophy

Question 4

What are the cellular markers for Synovial sarcoma?

Accepted Answer

All of the above

Answer

Cytokeratin

Answer

S-100

Answer

Vimentin

Question 5

Which is the most characteristic finding in Osteomalacia?

Accepted Answer

Increased deposition of osteoid with decreased mineralization

Answer

Abnormal osteoblastic activity

Answer

Crystalline structure of bone

Answer

Increased mineralization with decreased osteoid formation

Question 6

A cyst is found in place of a tooth. What is the likely diagnosis?

Accepted Answer

Primordial cyst

Answer

Dentigerous cyst

Answer

Eruption cyst

Answer

All of the above

Question 7

Which of the following are characteristic histological features of a unicameral bone cyst?

Accepted Answer

Blood-filled cavities

Answer

Endothelial lining

Answer

Giant cells

Answer

Bone formation

Question 8

Driven snow appearance is seen in which of the following conditions?

Accepted Answer

Pindborg tumor

Answer

Osteoid osteoma

Answer

Simple bone cyst

Answer

Aneurysmal bone cyst

Question 9

Which of the following conditions is characterized by unconjugated hyperbilirubinemia with increased urobilinogen?

Accepted Answer

Hemolytic anemia

Answer

Liver cirrhosis

Answer

Bile duct obstruction

Answer

Sclerosing cholangitis

Question 10

What is the most common malignant neoplasm of salivary gland origin that affects bones?

Accepted Answer

Mucoepidermoid carcinoma

Answer

Pleomorphic adenoma

Answer

Adenoid cystic carcinoma

Answer

Adenolymphoma

Bone and Soft Tissue Pathology — MCQs

Bone and Soft Tissue Pathology — MCQs

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