Diseases of the Oral Cavity and Salivary Glands — MCQs

Diseases of the Oral Cavity and Salivary Glands Indian Medical PG Practice Questions and MCQs

Question 51: A median round lesion located anterior to the circumvallate papillae, showing epithelial hyperplasia, is diagnosed as:

A. Median rhomboid glossitis (Correct Answer)
B. Erythema migrans
C. Aphthous ulcer
D. Chemical burn

Explanation: **Explanation:** **Median Rhomboid Glossitis (MRG)** is a clinical condition characterized by a well-demarcated, erythematous, depapillated area located in the **midline of the dorsum of the tongue**, specifically **anterior to the circumvallate papillae**. 1. **Why it is correct:** Historically thought to be a developmental defect (failure of the lateral lingual swellings to fuse over the tuberculum impar), it is now primarily considered a form of **chronic hyperplastic candidiasis**. Histologically, it shows **epithelial hyperplasia** (acanthosis) and a loss of filiform papillae, which matches the description in the question. Its classic location is always the midline, just anterior to the "V" of the circumvallate papillae. 2. **Why the other options are incorrect:** * **Erythema Migrans (Geographic Tongue):** Presents as multiple, migratory, red patches with white circumferential borders. It is not fixed to the midline. * **Aphthous Ulcer:** These are painful, shallow ulcers with a necrotic center and erythematous halo, typically found on non-keratinized mucosa (like the buccal mucosa), not as a hyperplastic midline lesion. * **Chemical Burn:** Presents as a painful, white, sloughing membrane (necrosis) following contact with agents like aspirin or phenol; it lacks the specific midline anatomical predilection. **High-Yield Clinical Pearls for NEET-PG:** * **Association:** Strongly associated with **Diabetes Mellitus**, immunosuppression, and smoking. * **Appearance:** Can be flat (atrophic) or raised (exophytic/nodular). * **"Kissing Lesion":** Often associated with a matching erythematous patch on the hard palate (contact candidiasis). * **Treatment:** Usually asymptomatic and requires no treatment; however, topical antifungals (Nystatin/Clotrimazole) are used if symptomatic.

Question 52: In which of the following conditions does internal derangement cause mandibular deviation to the same side?

A. Bilateral temporomandibular joint dislocation
B. Temporomandibular joint ankylosis
C. Unilateral temporomandibular joint dislocation
D. Unilateral disk displacement anteriorly without reduction (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Unilateral disk displacement anteriorly without reduction.** **1. Why Option D is Correct:** Internal derangement of the Temporomandibular Joint (TMJ) most commonly involves **anterior displacement of the articular disk**. In "displacement without reduction" (closed lock), the disk remains stuck anterior to the condyle, physically blocking its forward translation. During mouth opening, the affected side cannot slide forward (translate), while the healthy side translates normally. This asymmetry causes the mandible to **deviate toward the affected (same) side** upon opening. **2. Why Other Options are Incorrect:** * **A & C (TMJ Dislocation):** In dislocation, the condyle is displaced *anterior* to the articular eminence. In **unilateral dislocation**, the mandible deviates to the **opposite (contralateral) side** because the affected condyle is pushed forward and locked. In **bilateral dislocation**, the jaw is fixed in an open position with no lateral deviation. * **B (TMJ Ankylosis):** While unilateral ankylosis also causes deviation to the same side, it is characterized by a chronic, severe restriction of movement due to bony or fibrous fusion. "Internal derangement" specifically refers to the mechanical relationship between the disk and the condyle, making Option D the most precise answer for the mechanism described. **3. Clinical Pearls for NEET-PG:** * **Deviation Rule:** In TMJ hypomobility (Ankylosis, Disk displacement without reduction), the jaw deviates **TOWARDS** the lesion. In TMJ hypermobility/dislocation, the jaw deviates **AWAY** from the lesion. * **Clicking vs. Locking:** Disk displacement *with* reduction causes a "click" (disk snaps back). Disk displacement *without* reduction causes "locking" and deviation (disk stays stuck). * **Eagle’s Syndrome:** Often a differential for TMJ pain; involves an elongated styloid process causing pain on swallowing/turning the head.

Question 53: What is the standard airway management for Ludwig's Angina?

A. Tracheostomy
B. Cricothyroidotomy (Correct Answer)
C. Nasal intubation
D. Oral intubation

Explanation: **Explanation:** Ludwig’s Angina is a rapidly spreading cellulitis of the submandibular, sublingual, and submental spaces. The hallmark of this condition is the elevation and posterior displacement of the tongue, which leads to acute upper airway obstruction. **Why Cricothyroidotomy is the Correct Answer:** In the context of an acute, life-threatening airway obstruction where the anatomy of the upper airway is distorted by massive edema and tongue protrusion, **Cricothyroidotomy** is considered the standard emergency surgical airway. It is faster and easier to perform than a formal tracheostomy in a crisis. While fiberoptic intubation is often the preferred elective method, in an emergency "cannot intubate, cannot ventilate" scenario—typical of advanced Ludwig's—surgical access below the level of obstruction is mandatory. **Analysis of Incorrect Options:** * **Tracheostomy (A):** While a definitive airway, it is technically difficult in Ludwig’s Angina due to the "bull neck" appearance, massive soft tissue edema, and the patient's inability to extend the neck. It takes longer to perform than a cricothyroidotomy. * **Nasal/Oral Intubation (C & D):** These are often impossible or contraindicated in late stages. Blind intubation can trigger laryngospasm or cause the rupture of a potential abscess, leading to aspiration. Furthermore, the distorted anatomy makes visualization of the cords via direct laryngoscopy nearly impossible. **High-Yield Clinical Pearls for NEET-PG:** * **Source of Infection:** Most commonly the 2nd and 3rd lower molars (odontogenic). * **Key Signs:** Woody hard swelling of the neck, "Bull neck" appearance, and "Hot potato voice." * **Microbiology:** Usually polymicrobial (Streptococcus, Staphylococcus, and anaerobes). * **Management Priority:** 1. Airway maintenance; 2. Intravenous antibiotics; 3. Incision and drainage (if fluctuation is present or medical treatment fails).

Question 54: Stomatitis areata migrans is:

A. Fissured tongue.
B. Geographic tongue. (Correct Answer)
C. Median rhomboid glossitis.
D. Aguesia.

Explanation: **Explanation:** **Stomatitis areata migrans** is the clinical synonym for **Geographic Tongue** (also known as Benign Migratory Glossitis). 1. **Why Option B is Correct:** Geographic tongue is a benign inflammatory condition characterized by the loss of filiform papillae, resulting in smooth, red, depapillated areas surrounded by raised, grayish-white borders. The term "migrans" is used because these patches change shape, size, and location over time, "migrating" across the dorsal surface of the tongue. When similar lesions occur on other mucosal sites (like the labial or buccal mucosa), the condition is specifically termed *Erythema migrans* or *Stomatitis areata migrans*. 2. **Why Other Options are Incorrect:** * **A. Fissured tongue:** Also known as scrotal tongue, it involves deep grooves on the dorsal surface. While it frequently co-exists with geographic tongue, it is a distinct structural anomaly. * **C. Median rhomboid glossitis:** This is a persistent, asymptomatic red rhomboid-shaped patch in the midline of the posterior dorsal tongue, now considered a form of erythematous candidiasis. It does not "migrate." * **D. Aguesia:** This refers to the complete loss of taste sensation, which is a functional deficit rather than a structural mucosal lesion. **NEET-PG High-Yield Pearls:** * **Etiology:** Unknown, but strongly associated with **Psoriasis** (HLA-Cw6) and Atopy. * **Histopathology:** Shows "Munro’s microabscesses" (neutrophils in the epithelium), similar to psoriasis. * **Clinical Feature:** Usually asymptomatic, but may cause a burning sensation with spicy foods. * **Management:** Reassurance is the mainstay; topical steroids or zinc supplements may be used for symptomatic cases.

Question 55: What is the most common benign salivary gland tumor?

A. Pleomorphic adenoma (Correct Answer)
B. Warthin's tumor
C. Mucoepidermoid carcinoma
D. Adenoid cystic carcinoma

Explanation: **Explanation:** **Pleomorphic Adenoma (Benign Mixed Tumor)** is the most common salivary gland tumor overall, accounting for approximately 60–70% of all salivary gland neoplasms. It most frequently involves the **parotid gland** (80% of cases), specifically the superficial lobe. It is termed "mixed" because it contains both epithelial and mesenchymal components (myxoid, chondroid, or osteoid tissue). **Analysis of Options:** * **Warthin’s Tumor (Papillary Cystadenoma Lymphomatosum):** This is the second most common benign salivary gland tumor. It is unique because it is almost exclusively found in the parotid gland, is often bilateral (10%), and has a strong association with **smoking**. * **Mucoepidermoid Carcinoma:** This is the most common **malignant** salivary gland tumor in both adults and children. While common, its overall incidence is lower than that of the benign Pleomorphic Adenoma. * **Adenoid Cystic Carcinoma:** This is a malignant tumor known for its **perineural invasion** (causing pain and nerve palsies) and a "Swiss-cheese" appearance on histology. It is the most common malignant tumor of the submandibular and minor salivary glands. **NEET-PG High-Yield Pearls:** * **Rule of 80s for Parotid Tumors:** 80% are benign, 80% are Pleomorphic Adenomas, 80% occur in the superficial lobe. * **Most common site for minor salivary gland tumors:** Palate. * **Clinical presentation:** Pleomorphic adenoma typically presents as a slow-growing, painless, firm, mobile mass. Sudden rapid growth or facial nerve palsy suggests malignant transformation into **Carcinoma ex-pleomorphic adenoma**. * **Treatment of choice:** Superficial parotidectomy (Enucleation is avoided due to high recurrence rates from pseudopod extensions).

Question 56: What is the most common site for salivary gland calculi?

A. Parotid
B. Submandibular (Correct Answer)
C. Sublingual
D. Minor salivary glands

Explanation: **Explanation:** The **submandibular gland** is the most common site for salivary calculi (sialolithiasis), accounting for approximately **80%** of all cases. This high incidence is attributed to several anatomical and physiological factors: 1. **Wharton’s Duct Anatomy:** The duct is long and follows an upward, tortuous course, leading to stasis of saliva against gravity. 2. **Saliva Composition:** Submandibular saliva is more **alkaline** and has a higher concentration of **calcium and phosphate** salts compared to parotid saliva. 3. **Mucin Content:** It contains a higher concentration of mucus, making the secretions more viscous. 4. **Punctum Size:** The ductal opening (punctum) is narrower than the lumen of the duct, predisposing it to obstruction. **Analysis of Incorrect Options:** * **Parotid Gland (A):** Accounts for about 15–20% of cases. Parotid saliva is serous (watery) and acidic, which keeps calcium salts in solution, making stone formation less likely. * **Sublingual (C) & Minor Salivary Glands (D):** These account for less than 5% of cases combined. Stones here are rare and usually present as small, firm nodules. **High-Yield Clinical Pearls for NEET-PG:** * **Radiopacity:** 80% of submandibular stones are **radiopaque** (visible on X-ray), whereas 80% of parotid stones are **radiolucent**. * **Best Imaging:** The **Intraoral Periapical (IOPA)** or **Occlusal view** is the best initial X-ray for submandibular stones. * **Clinical Presentation:** "Mealtime syndrome"—recurrent, painful swelling of the gland triggered by the sight or smell of food. * **Management:** Small stones may be massaged out; larger stones require **Sialendoscopy** or surgical removal.

Question 57: What is the most common site for Adenoid cystic carcinoma?

A. Minor salivary glands (Correct Answer)
B. Parotid gland
C. Submandibular gland
D. Sublingual gland

Explanation: **Explanation:** Adenoid cystic carcinoma (ACC) is a unique salivary gland malignancy known for its indolent but relentless growth and a high propensity for **perineural invasion**. **1. Why Minor Salivary Glands are correct:** While the parotid gland is the most common site for salivary tumors overall, the distribution of malignancy changes as the glands get smaller. In the **minor salivary glands**, approximately 50% of all tumors are malignant, and **Adenoid cystic carcinoma is the most common malignancy** found at this site (specifically the palate). Conversely, in the parotid, the vast majority of tumors are benign (Pleomorphic adenoma). **2. Analysis of Incorrect Options:** * **Parotid Gland:** This is the most common site for salivary gland tumors in general, but the most common malignancy here is **Mucoepidermoid carcinoma**, not ACC. * **Submandibular Gland:** ACC is the most common malignancy of this gland, but in terms of absolute frequency across the body, it occurs more often in the minor salivary glands. * **Sublingual Gland:** While tumors here are rare and 80% are malignant, the total volume of cases is significantly lower than those found in the minor salivary glands. **3. NEET-PG High-Yield Pearls:** * **Histology:** Classically shows a **"Swiss-cheese" appearance** (Cribriform pattern). * **Clinical Feature:** Characterized by early **perineural spread**, often leading to "skip lesions" and local recurrence. * **Prognosis:** It has a good 5-year survival rate but a **poor 15-20 year survival rate** due to late distant metastasis (most commonly to the **Lungs**). * **Rule of Thumb:** The smaller the salivary gland, the higher the chance that a lump is malignant.

Question 58: Which of the following is an example of a scrapable white lesion?

A. Diphtheritic patch
B. Syphilitic mucous patch
C. Pseudomembranous candidiasis
D. All of the above (Correct Answer)

Explanation: ### Explanation The core clinical concept here is the differentiation of white lesions of the oral cavity based on their adherence to the underlying mucosa. **Scrapable white lesions** are those where the white material (pseudomembrane, debris, or fungal hyphae) can be removed with a tongue depressor, often leaving behind an erythematous or bleeding base. **Why "All of the Above" is correct:** 1. **Pseudomembranous Candidiasis (Oral Thrush):** This is the classic example of a scrapable lesion. It consists of desquamated epithelial cells, fibrin, and fungal hyphae. When scraped, it reveals a raw, friable, and bleeding surface. 2. **Diphtheritic Patch:** Caused by *Corynebacterium diphtheriae*, this is a "true" pseudomembrane. While it is strongly adherent, it is technically a scrapable membrane; however, scraping it is clinically discouraged because it causes profuse bleeding and may facilitate systemic absorption of the diphtheria toxin. 3. **Syphilitic Mucous Patch:** Seen in secondary syphilis, these are shallow ulcers covered by a grayish-white membrane. This membrane is loosely adherent and can be scraped off. **Clinical Pearls for NEET-PG:** * **Non-Scrapable Lesions:** The most important differential is **Leukoplakia**, which is a clinical diagnosis of exclusion and **cannot** be scraped off. Other non-scrapable lesions include Lichen Planus and Oral Submucous Fibrosis (OSMF). * **The "Bleeding Base" Sign:** If a white patch scrapes off and bleeds, think Candidiasis or Diphtheria. * **EBV Association:** Hairy Leukoplakia (seen in HIV) occurs on the lateral borders of the tongue and is also **non-scrapable**, distinguishing it from Candidiasis. * **Diphtheria Key Point:** The membrane in Diphtheria is unique because it often extends beyond the tonsils to the soft palate and uvula.

Question 59: Reduction in the flow of saliva is not generally seen in which of the following conditions?

A. Elderly diabetics
B. Patients undergoing radiation therapy
C. Patients suffering from Parkinsonism (Correct Answer)
D. Patients on phenothiazine drugs

Explanation: **Explanation:** The core concept tested here is the distinction between **Xerostomia** (dry mouth) and **Sialorrhea** (excessive salivation/drooling). **Why Parkinsonism is the correct answer:** In **Parkinson’s disease**, patients actually experience **Sialorrhea** (drooling). This is not typically due to an absolute increase in saliva production, but rather due to **infrequent spontaneous swallowing** and poor neuromuscular coordination of the oral phase of deglutition. Because the saliva is not cleared effectively, it pools in the mouth and leaks out, representing an *apparent* increase in flow rather than a reduction. **Analysis of Incorrect Options (Conditions causing reduced saliva):** * **Elderly Diabetics:** Uncontrolled diabetes causes dehydration and autonomic neuropathy, both of which lead to decreased salivary gland function and xerostomia. * **Radiation Therapy:** Radiotherapy for head and neck cancers causes permanent damage to the serous acini of the salivary glands (especially the parotid), leading to severe, often irreversible xerostomia. * **Phenothiazine Drugs:** These are antipsychotics with significant **anticholinergic properties**. Since salivary secretion is primarily mediated by parasympathetic (cholinergic) stimulation, these drugs block the receptors, leading to a dry mouth. **NEET-PG High-Yield Pearls:** * **Drugs causing Xerostomia:** Atropine, Antihistamines, Tricyclic Antidepressants (TCAs), Phenothiazines, and Diuretics. * **Drugs causing Sialorrhea:** Pilocarpine (miotic), Physostigmine, and Lithium. * **Sjögren’s Syndrome:** A classic autoimmune cause of xerostomia (keratoconjunctivitis sicca + xerostomia). * **Frey’s Syndrome:** Gustatory sweating following parotid surgery due to aberrant reinnervation of sweat glands by auriculotemporal nerve fibers.

Question 60: Each of the following cysts is associated with an impacted tooth except:

A. Dentigerous cyst
B. Calcifying epithelial odontogenic cyst
C. Keratocyst
D. Primordial cyst (Correct Answer)

Explanation: ### Explanation The key to answering this question lies in understanding the **origin** of the cyst relative to the tooth germ. **Why Primordial Cyst is the correct answer:** A **Primordial cyst** develops **in place of a tooth** rather than being associated with an existing impacted one. It arises from the degeneration of the enamel organ before any mineralized dental tissues are formed. Therefore, the tooth that should have been there is **clinically missing** from the dental arch, and the cyst occupies its space. **Analysis of Incorrect Options:** * **Dentigerous Cyst (Follicular Cyst):** This is the most common cyst associated with an impacted tooth. It originates from the reduced enamel epithelium and attaches to the **cemento-enamel junction (CEJ)**, enclosing the crown of an unerupted tooth (most commonly the mandibular 3rd molar). * **Calcifying Epithelial Odontogenic Cyst (Gorlin Cyst):** This is a rare odontogenic lesion that can be associated with an impacted tooth in about 25-30% of cases. It is characterized by "ghost cells" on histology. * **Odontogenic Keratocyst (OKC):** While OKCs can occur anywhere, a significant percentage (approx. 25-40%) are found in a "dentigerous relationship," surrounding the crown of an impacted tooth, particularly in the molar-ramus area of the mandible. **NEET-PG High-Yield Pearls:** 1. **Most common odontogenic cyst:** Radicular cyst (inflammatory). 2. **Most common developmental odontogenic cyst:** Dentigerous cyst. 3. **OKC Hallmark:** High recurrence rate, associated with **Gorlin-Goltz Syndrome** (PTCH gene mutation), and shows "picket fence" or "tombstone" appearance of the basal layer. 4. **Radiographic feature of Dentigerous cyst:** Well-defined unilocular lucency attached to the neck of an impacted tooth.

Practice by Chapter

Stomatitis

Practice Questions

Oral Ulcers

Practice Questions

Oral Leukoplakia

Practice Questions

Oral Cancers

Practice Questions

Sialadenitis

Practice Questions

Sialolithiasis

Practice Questions

Salivary Gland Tumors

Practice Questions

Ranula

Practice Questions

Xerostomia

Practice Questions

Sjögren's Syndrome

Practice Questions

Oral Manifestations of Systemic Diseases

Practice Questions

Temporomandibular Joint Disorders

Practice Questions

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