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 291: What is the investigation of choice for parotid fistula?

A. CT Scan
B. X-ray
C. Starch iodine Test
D. Sialogram (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Sialogram** **Why it is the Investigation of Choice:** A **sialogram** (sialography) is the gold standard for investigating a parotid fistula. It involves the injection of a radio-opaque contrast medium into the Stensen’s duct followed by imaging. In the case of a fistula, the contrast will be seen leaking from the ductal system or gland parenchyma into the fistulous tract, effectively demonstrating the **site, size, and origin** of the leak. It also helps differentiate between a ductal fistula (injury to the main duct) and a glandular fistula (injury to the parenchyma), which is crucial for surgical planning. **Analysis of Incorrect Options:** * **A. CT Scan:** While useful for identifying tumors or abscesses, a routine CT lacks the dynamic contrast flow needed to pinpoint a fine fistulous communication. * **B. X-ray:** Plain radiographs are primarily used to detect radiopaque sialoliths (stones) but cannot visualize soft tissue tracts or fluid leaks. * **C. Starch Iodine Test (Minor’s Test):** This is the investigation of choice for **Frey’s Syndrome** (gustatory sweating), not a parotid fistula. It identifies sweat production on the skin, whereas a fistula involves the leakage of saliva. **High-Yield Clinical Pearls for NEET-PG:** * **Frey’s Syndrome:** Occurs due to aberrant regeneration of auriculotemporal nerve fibers. * **Management of Parotid Fistula:** Initial management is conservative (anti-sialagogues like Glycopyrrolate, pressure dressings). If it fails, surgical options include tympanic neurectomy (to cut parasympathetic supply) or parotidectomy. * **Sialography Contraindication:** It should never be performed during **acute infection** (sialadenitis) as it can retrograde spread the infection.

Question 292: What is the treatment for leukoplakia?

A. Radiation therapy
B. Surgical excision and cryotherapy (Correct Answer)
C. Topical chemotherapy
D. Repositioning of ill-fitting dentures

Explanation: **Explanation:** **Leukoplakia** is defined by the WHO as a clinical white patch or plaque that cannot be characterized clinically or pathologically as any other disease. It is a **premalignant condition** with a risk of transformation into squamous cell carcinoma. **1. Why Surgical Excision and Cryotherapy are correct:** The primary goal of treating leukoplakia is to eliminate the lesion to prevent malignant transformation. * **Surgical Excision:** This is the treatment of choice as it allows for a complete histopathological examination of the specimen to rule out occult invasive carcinoma. * **Cryotherapy:** This is an effective alternative for superficial or widespread lesions where surgical closure might be difficult. Other modalities include CO2 laser ablation, which provides excellent precision and minimal scarring. **2. Why the other options are incorrect:** * **Option A (Radiation therapy):** Radiation is contraindicated for premalignant lesions. It can induce further DNA damage, potentially accelerating malignant transformation or causing osteoradionecrosis. * **Option C (Topical chemotherapy):** While agents like Bleomycin or 5-Fluorouracil have been studied, they are not the standard of care due to high recurrence rates and the inability to provide a tissue diagnosis. * **Option D (Repositioning dentures):** While removing irritants (smoking, ill-fitting dentures) is the first step in management, it is a **preventive measure**, not the definitive treatment for an established leukoplakia. If a lesion persists 2–3 weeks after removing the irritant, it must be biopsied and treated. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Buccal mucosa and commissures. * **Highest risk of malignancy:** **Erythroplakia** (higher than leukoplakia) and **Speckled leukoplakia** (Non-homogeneous type). * **Microscopic hallmark:** Hyperkeratosis, acanthosis, and varying degrees of dysplasia. * **Biopsy:** Always mandatory before definitive treatment to assess the degree of dysplasia.

Question 293: All of the following are true about dental abnormalities EXCEPT:

A. Dental cysts develop at the apices of carious teeth with necrotic pulp.
B. Dentigerous cysts contain unerupted teeth.
C. Dentigerous cysts are most common in the upper third molars. (Correct Answer)
D. Ameloblastoma is the most common odontogenic tumor.

Explanation: ### Explanation **1. Why Option C is the Correct Answer (The Exception):** Dentigerous cysts (follicular cysts) are the second most common type of odontogenic cysts. While they are associated with unerupted teeth, they are most commonly found in the **mandibular (lower) third molars**, followed by the maxillary canines. The statement claiming they are most common in the upper third molars is factually incorrect, making it the right choice for an "EXCEPT" question. **2. Analysis of Other Options:** * **Option A:** **Dental (Radicular) cysts** are the most common odontogenic cysts. They result from inflammation at the root apex (periapical) of a non-vital, carious tooth, leading to the proliferation of the rests of Malassez. * **Option B:** **Dentigerous cysts** originate from the reduced enamel epithelium around the crown of an **unerupted tooth**. Radiologically, they appear as a well-defined radiolucency attached to the cemento-enamel junction. * **Option D:** **Ameloblastoma** is indeed the most common odontogenic tumor. It is a benign but locally aggressive neoplasm, most frequently occurring in the molar-ramus region of the mandible. It characteristically shows a "soap-bubble" or "honeycomb" appearance on X-ray. **3. NEET-PG High-Yield Pearls:** * **Most common odontogenic cyst:** Radicular (Dental) cyst. * **Most common odontogenic tumor:** Ameloblastoma. * **Pindborg Tumor:** Calcifying epithelial odontogenic tumor (CEOT) – look for "driven snow" appearance on X-ray. * **Odontoma:** Most common odontogenic "hamartoma" (often confused with tumors). * **Dentigerous Cyst Complication:** If left untreated, it can transform into an Ameloblastoma or Squamous Cell Carcinoma.

Question 294: What is the most common site for a minor salivary gland tumor?

A. Cheek
B. Palate (Correct Answer)
C. Sublingual gland
D. Tongue

Explanation: **Explanation:** The **palate** (specifically the junction of the hard and soft palate) is the most common site for minor salivary gland tumors [1], accounting for approximately **50%** of all such cases. Minor salivary glands are distributed throughout the upper aerodigestive tract, but their highest density is found in the palatal mucosa. **Analysis of Options:** * **B. Palate (Correct):** Due to the high concentration of minor salivary tissue, this is the primary site [1]. A key surgical pearl is that a swelling on the palate is more likely to be a minor salivary gland tumor than a primary bone tumor. * **A. Cheek (Buccal Mucosa):** While minor salivary glands exist here, tumors are significantly less common than in the palate. * **C. Sublingual Gland:** This is a **major** salivary gland, not a minor one. While it is the least common site for major salivary gland tumors, it has the highest malignancy rate (approx. 80%). * **D. Tongue:** Tumors can occur here (usually at the base or lateral borders), but the frequency is much lower compared to the palatal distribution. **High-Yield NEET-PG Pearls:** 1. **The 50% Rule:** Approximately 50% of all minor salivary gland tumors are **malignant** [2] (unlike the parotid, where 80% are benign). 2. **Most Common Benign Minor Tumor:** Pleomorphic Adenoma (most common site: Palate [1]). 3. **Most Common Malignant Minor Tumor:** Adenoid Cystic Carcinoma (most common site: Palate). 4. **Overall Most Common Salivary Tumor:** Pleomorphic Adenoma of the Parotid Gland.

Question 295: All the following are true regarding a ranula EXCEPT?

A. A cyst with an epithelial lining, confined to the sublingual salivary gland (Correct Answer)
B. A pseudocyst with no connection to the salivary gland
C. Will change size following chewing and swallowing
D. Formed due to obstruction of the submandibular or minor salivary glands

Explanation: ### Explanation **Ranula** is a clinical term for a mucocele (mucus extravasation cyst) occurring specifically in the floor of the mouth. **1. Why Option A is the Correct Answer (The Exception):** A ranula is **not a true cyst**; it is a **pseudocyst**. By definition, a true cyst is lined by epithelium. A ranula is formed by the extravasation of mucus into the surrounding soft tissues, resulting in a wall composed of **granulation or fibrous tissue**, not epithelium. While most commonly associated with the sublingual gland, it is not strictly "confined" to it, as "plunging" variants can extend into the submandibular space. **2. Analysis of Other Options:** * **Option B:** Correct statement. Because it lacks an epithelial lining, it is classified as a pseudocyst. It is caused by mucus escape rather than a direct anatomical "connection" or ductal dilation. * **Option C:** Correct statement. Salivary flow increases during mastication (chewing) and swallowing. Since the mucus cannot drain normally, the extravasation increases, causing the swelling to fluctuate in size in relation to meals. * **Option D:** Correct statement. While the **sublingual gland** (specifically the ducts of Rivinus) is the most common source, trauma or obstruction of the submandibular duct or minor salivary glands in the floor of the mouth can also lead to ranula formation. **3. High-Yield Clinical Pearls for NEET-PG:** * **Appearance:** It presents as a translucent, bluish, painless swelling in the floor of the mouth, resembling a "frog’s belly" (Latin: *Rana*). * **Plunging Ranula:** Occurs when mucus herniates through the **mylohyoid muscle**, presenting as a neck swelling in the submandibular region. * **Treatment of Choice:** **Surgical excision** of the ranula along with the offending **sublingual gland**. Simple marsupialization has a high recurrence rate. * **Differential Diagnosis:** Dermoid cyst (usually midline and opaque) and Hemangioma.

Question 296: What is the best method to differentiate a periapical cyst from a periapical granuloma?

A. Radiographically
B. Histologically (Correct Answer)
C. Clinically
D. None of the above

Explanation: ### Explanation The differentiation between a periapical cyst (radicular cyst) and a periapical granuloma is a classic dilemma in oral pathology. While both represent inflammatory responses to a non-vital tooth, the **gold standard** for differentiation is **histological examination**. **1. Why Histology is Correct:** The defining feature of a **periapical cyst** is the presence of a pathological cavity lined by **stratified squamous epithelium** (derived from the Malassez epithelial rests). In contrast, a **periapical granuloma** consists of a solid mass of chronic inflammatory tissue (lymphocytes, plasma cells, and macrophages) and granulation tissue **without** an epithelial lining. Since this distinction is microscopic, only a biopsy can provide a definitive diagnosis. **2. Why Other Options are Incorrect:** * **Radiographically:** Both lesions appear as well-defined radiolucencies at the apex of a tooth. While cysts are often larger (>20mm) and have a sclerotic border, these features are not pathognomonic. Studies show that radiographic interpretation alone is unreliable for distinguishing between the two. * **Clinically:** Both conditions are often asymptomatic and associated with a non-vital (necrotic) tooth. They may both present with mild swelling or sensitivity to percussion, making clinical differentiation impossible. **High-Yield Clinical Pearls for NEET-PG:** * **Periapical Granuloma:** The most common sequel of chronic pulpitis. It is *not* a true granuloma (lacks epithelioid histiocytes/giant cells). * **Radicular Cyst:** The most common cyst of the jaws. * **Rushton Bodies:** Eosinophilic, linear, or curved inclusions found in the epithelial lining of radicular cysts (High-yield histological finding). * **Treatment:** Both usually respond to Root Canal Treatment (RCT); however, large cysts may require surgical enucleation.

Question 297: Which of the following is the most common tumor of the salivary gland?

A. Mucoepidermoid tumor
B. Warthin's tumor
C. Acinic cell tumor
D. Pleomorphic adenoma (Correct Answer)

Explanation: **Explanation:** **Pleomorphic Adenoma** (Option D) is the most common tumor of the salivary glands, accounting for approximately 60–70% of all salivary gland neoplasms. It is a benign mixed tumor containing both epithelial and mesenchymal elements. It most frequently involves the **parotid gland** (80% of cases), where it typically presents as a slow-growing, painless, firm swelling in the superficial lobe. **Analysis of Incorrect Options:** * **Mucoepidermoid Carcinoma (Option A):** 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. * **Warthin’s Tumor (Option B):** Also known as Papillary Cystadenoma Lymphomatosum, it is the second most common benign tumor of the parotid. It is strongly associated with smoking and is the most common salivary tumor to present bilaterally or multicentrically. * **Acinic Cell Tumor (Option C):** This is a low-grade malignant tumor. It is unique because it is often bilateral (second only to Warthin’s) but is significantly rarer than Pleomorphic Adenoma. **High-Yield NEET-PG Pearls:** * **Rule of 80s for Parotid Tumors:** 80% are parotid, 80% are benign, 80% are Pleomorphic Adenoma, and 80% occur in the superficial lobe. * **Most common site for minor salivary gland tumors:** The Palate. * **Malignancy Risk:** The smaller the gland, the higher the risk of malignancy (e.g., Sublingual gland tumors are rare but ~80% are malignant). * **Carcinoma ex pleomorphic adenoma:** Refers to the malignant transformation of a long-standing Pleomorphic Adenoma.

Question 298: Which of the following is not an indication for radiotherapy in pleomorphic adenoma of the parotid gland?

A. Involvement of the deep lobe
B. Second histologically benign recurrence (Correct Answer)
C. Microscopically positive margins
D. Malignant transformation

Explanation: **Explanation:** Pleomorphic adenoma is the most common benign tumor of the parotid gland. While primarily managed surgically (Superficial or Total Parotidectomy), radiotherapy (RT) is reserved for specific high-risk scenarios to prevent further recurrence or manage malignancy. **Why "Second histologically benign recurrence" is the correct answer:** According to standard oncological guidelines (including NCCN and major ENT textbooks like Cummings), a **first or second recurrence** of a histologically benign pleomorphic adenoma is typically managed by **surgical re-excision**. Radiotherapy is generally avoided in benign recurrences due to the risk of radiation-induced secondary malignancies (like post-radiation sarcoma) and the difficulty it adds to future surgeries. RT is usually considered only for *multiple* recurrences (usually 3rd or more) or when surgical morbidity is unacceptably high. **Analysis of Incorrect Options:** * **Involvement of the deep lobe:** Large tumors or those involving the deep lobe often have a higher risk of incomplete resection or "spillage" during surgery due to proximity to the facial nerve, making RT a viable adjuvant consideration. * **Microscopically positive margins:** If the tumor capsule is breached or margins are positive, the risk of recurrence is extremely high. Adjuvant RT is indicated to sterilize the surgical bed. * **Malignant transformation:** If a pleomorphic adenoma transforms into **Carcinoma ex-pleomorphic adenoma**, it is treated as a parotid malignancy, where postoperative RT is a standard indication. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Superficial lobe of the parotid. * **Pathology:** Characterized by "mixed" appearance (epithelial and mesenchymal elements). * **Treatment of choice:** Superficial parotidectomy with facial nerve preservation. * **Enucleation:** Strictly contraindicated due to high recurrence rates (pseudopodial extensions). * **Frey’s Syndrome:** The most common late complication of parotid surgery (diagnosed by Minor’s Starch-Iodine test).

Question 299: Pain in the tonsillar fossa and upper neck is characteristic of?

A. Eagle's syndrome (Correct Answer)
B. Ape's syndrome
C. Sickler's syndrome
D. Usher's syndrome

Explanation: **Explanation:** **Eagle’s Syndrome** (also known as Stylohyoid Syndrome) occurs due to an **elongated styloid process** (greater than 3 cm) or calcification of the stylohyoid ligament. This anatomical variation causes compression of cranial nerves (V, VII, IX, or X) or the carotid arteries. Patients typically present with a dull, nagging pain in the **tonsillar fossa and upper neck**, often triggered by swallowing or turning the head. A sensation of a "foreign body" in the throat (globus pharyngeus) and referred otalgia are also common. Diagnosis is confirmed by palpating the styloid process in the tonsillar fossa and via imaging (X-ray or CT). **Analysis of Incorrect Options:** * **Ape’s Syndrome:** This is not a recognized medical term. It is likely a distractor for "Apert Syndrome," which is a craniofacial synostosis characterized by skull deformities and syndactyly (fused fingers/toes). * **Sickler’s Syndrome:** This is a distractor. "Sickle Cell Disease" is a hematological disorder, and "Stickler Syndrome" is a genetic connective tissue disorder involving hearing loss and retinal detachment, but neither presents with localized tonsillar fossa pain. * **Usher’s Syndrome:** A genetic condition characterized by the combination of sensorineural hearing loss and progressive vision loss due to retinitis pigmentosa. **Clinical Pearls for NEET-PG:** * **Treatment:** The definitive treatment is surgical shortening of the styloid process via a **trans-oral** or **trans-cervical** approach. * **Differential Diagnosis:** Must be differentiated from Glossopharyngeal Neuralgia (which presents with paroxysmal, lancinating pain). * **Anatomy:** The styloid process is derived from the **2nd branchial arch** (Reichert’s cartilage).

Question 300: In Frey's syndrome, what is the neurotransmitter involved?

A. Acetylcholine (Correct Answer)
B. Epinephrine
C. Norepinephrine
D. Serotonin

Explanation: **Explanation:** **Frey’s Syndrome (Auriculotemporal Syndrome)** occurs due to the aberrant regeneration of nerve fibers following parotid surgery (parotidectomy) or trauma. 1. **Why Acetylcholine is correct:** The physiological basis of this syndrome lies in the **parasympathetic** nervous system. Normally, the **auriculotemporal nerve** carries postganglionic parasympathetic fibers that use **acetylcholine** to stimulate salivary secretion from the parotid gland. After injury, these regenerating parasympathetic fibers mistakenly grow into the overlying skin to innervate sweat glands and small blood vessels. Since sweat glands are also stimulated by cholinergic (acetylcholine) fibers, the stimulus intended for salivation (like seeing or smelling food) results in localized sweating and flushing of the temple area instead. 2. **Why the other options are incorrect:** * **Epinephrine & Norepinephrine:** These are the primary neurotransmitters of the sympathetic nervous system. While sweat glands are anatomically part of the sympathetic system, they are a unique exception as they are **cholinergic** (stimulated by acetylcholine). * **Serotonin:** This is a monoamine neurotransmitter primarily involved in mood regulation and GI motility; it has no role in the secretomotor pathway of the parotid or sweat glands. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Confirmed by the **Minor’s Starch-Iodine Test** (the area turns blue-black upon sweating). * **Prevention:** Interposition of barriers like the **Acellular Dermal Matrix** or **Sternocleidomastoid (SCM) flap** during surgery. * **Treatment:** Topical **Glycopyrrolate** or **Botulinum toxin (Botox)** injections (which block acetylcholine release).

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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