Diseases of the Oral Cavity and Salivary Glands Practice Questions

Q: True regarding Warthin's tumor?

Shows a hot spot on technetium-99m scan. **Explanation:** **Warthin’s Tumor (Papillary Cystadenoma Lymphomatosum)** is the second most common benign tumor of the parotid gland. **Why Option A is Correct:** Warthin’s tumor is unique because it is an **oncocytic tumor**. The cells contain a high density of mitochondria which actively take up and retain **Technetium-99m pertechnetate**. Unlike most other salivary tumors which appear as "cold" (non-functional) areas, Warthin’s tumor (and Oncocytoma) shows up as a **"hot spot"** on a radionuclide scan. **Analysis of Incorrect Options:** * **Option B:** The most common tumor of the minor salivary glands is **Pleomorphic Adenoma** (benign) or **Adenoid Cystic Carcinoma** (malignant). Warthin’s tumor almost exclusively occurs in the parotid gland (specifically the tail). * **Option C:** Warthin’s tumor is a **benign** neoplasm. The most common malignant tumor of the salivary glands is **Mucoepidermoid Carcinoma**. * **Option D:** Warthin’s tumor is significantly more **common in males** (though the gap is narrowing) and is strongly associated with **smoking**. **High-Yield Clinical Pearls for NEET-PG:** * **Location:** Most common tumor to occur **bilaterally** (10%) or multicentrically. * **Origin:** Arises from salivary gland tissue entrapped in parotid lymph nodes during embryogenesis. * **Histology:** Characterized by a **double layer of oncocytic epithelium** and a dense **lymphoid stroma** with germinal centers. * **Risk Factor:** Smoking is the most significant risk factor. * **Treatment:** Superficial parotidectomy or Enucleation (low recurrence rate).

Q: A 45-year-old man presents with a small mass in his oral cavity. Physical examination reveals left facial nerve palsy and a firm, mobile, painless mass in the left parapharyngeal space. Biopsy of the oral cavity mass shows chondromyxoid stroma and epithelium. Which of the following best explains this mass?

The mass represents the most common salivary gland tumor.. ### Explanation The clinical presentation and histopathology point toward **Pleomorphic Adenoma** (Benign Mixed Tumor). **1. Why the Correct Answer is Right:** The biopsy finding of **chondromyxoid stroma** (mesenchymal component) and **epithelium** (epithelial component) is pathognomonic for Pleomorphic Adenoma. It is the **most common salivary gland tumor** overall, accounting for approximately 80% of parotid tumors. While typically found in the superficial lobe of the parotid, it can arise from the deep lobe, presenting as a **parapharyngeal space mass** that bulges into the oral cavity/oropharynx. Although benign, deep lobe tumors can occasionally compress the facial nerve, though frank palsy is more common in malignancy. **2. Why the Incorrect Options are Wrong:** * **Option A:** Pleomorphic adenomas have a high rate of **recurrence** if simple enucleation is performed. This is due to "pseudopods" (finger-like projections) and a friable capsule that can rupture, seeding the surgical field. * **Option B:** This describes **Warthin’s Tumor** (Adenolymphoma), which is characterized by a double layer of oncocytic epithelium and a dense lymphoid stroma with germinal centers. * **Option C:** The most common malignant salivary gland tumor is **Mucoepidermoid Carcinoma**. While Pleomorphic Adenoma is the most common tumor overall, it is histologically benign. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Parotid gland (Superficial lobe). * **Most common minor salivary gland site:** Palate. * **Carcinoma ex-pleomorphic adenoma:** A malignant transformation (usually into an adenocarcinoma) that should be suspected if a long-standing stable mass suddenly grows rapidly or causes nerve palsy. * **Treatment of choice:** Superficial parotidectomy (with nerve preservation). Never perform an incisional biopsy; use FNAC instead.

Q: Which jaw cyst is premalignant?

Odontogenic keratocyst. **Explanation:** **Odontogenic Keratocyst (OKC)**, recently also known as Keratocystic Odontogenic Tumor (KCOT), is considered premalignant because of its aggressive clinical behavior, high recurrence rate, and its potential to undergo neoplastic transformation into Squamous Cell Carcinoma. Unlike other cysts, its lining is derived from the **dental lamina** and possesses an innate growth potential similar to a benign tumor. Histologically, it is characterized by a thin, friable wall and a parakeratinized stratified squamous epithelium. **Why other options are incorrect:** * **Radicular Cyst (Option A) & Dental Cyst (Option B):** These are synonymous. They are the most common inflammatory odontogenic cysts, usually occurring at the apex of a non-vital tooth. They are inflammatory in origin, not neoplastic, and have a very low potential for malignant change. * **Dentigerous Cyst (Option D):** This is a follicular cyst that surrounds the crown of an unerupted tooth (most commonly the mandibular 3rd molar). While it can occasionally transform into an Ameloblastoma or Mucoepidermoid carcinoma, it is primarily considered a developmental cyst rather than a classic premalignant lesion like OKC. **High-Yield Clinical Pearls for NEET-PG:** * **Gorlin-Goltz Syndrome:** Multiple OKCs are a hallmark of this syndrome (along with Basal Cell Carcinomas and bifid ribs). * **Aspiration:** OKC often contains a "cheesy" or "creamy" white material (keratin) with low soluble protein levels (<4g/dL). * **Radiology:** Typically appears as a well-defined multilocular or unilocular radiolucency, often in the **posterior body or ramus of the mandible**. * **Treatment:** Due to high recurrence, treatment often involves enucleation with **Carnoy’s solution** application or marsupialization.

Q: A white persistent patch in the mouth most commonly indicates which of the following?

Streptococcal infection. The correct answer is **B. Streptococcal infection**. ### **Explanation** A persistent white patch in the oral cavity is clinically defined as **Leukoplakia**. However, in the context of acute infections, a white patch or exudate on the tonsils or oropharynx is most commonly associated with **Group A Beta-Hemolytic Streptococcus (GABHS)**. In the clinical setting of a "white patch" appearing as a pseudomembrane or exudative coating, streptococcal pharyngitis/tonsillitis is the most frequent bacterial cause encountered in general practice. ### **Analysis of Options** * **A. Mucormycosis:** This is a fulminant fungal infection typically seen in immunocompromised or uncontrolled diabetic patients. It is characterized by **black eschar** (necrosis) due to angioinvasion, rather than a simple white patch. * **C. Erythroplakia:** This refers to a persistent **red patch** in the oral cavity. While it is a significant premalignant condition, it does not present as a white lesion. (Note: Leukoplakia is the term for a white patch). * **D. None of the above:** Incorrect, as Streptococcal infection is a recognized cause of white exudative patches. ### **NEET-PG High-Yield Pearls** * **Leukoplakia:** Defined by WHO as a "white patch or plaque that cannot be characterized clinically or pathologically as any other disease." It is the most common **premalignant** lesion of the oral cavity. * **Erythroplakia:** Has a much higher risk of malignancy (up to 90% show dysplasia or carcinoma) compared to leukoplakia. * **Membranous Tonsillitis:** Differential diagnosis for a white/greyish membrane includes **Diphtheria** (bleeds on removal), **Infectious Mononucleosis** (Epstein-Barr Virus), and **Vincent’s Angina**. * **Oral Candidiasis (Thrush):** A white patch that **can be scraped off**, leaving an erythematous base.

Q: Frey's syndrome is due to involvement of which nerve?

Auriculotemporal nerve. **Explanation:** **Frey’s Syndrome (Gustatory Sweating)** is a common complication following parotidectomy or trauma to the parotid region. It occurs due to the **aberrant regeneration** of nerve fibers. **Why Auriculotemporal Nerve is Correct:** The auriculotemporal nerve (a branch of the mandibular nerve, V3) carries two types of fibers: 1. **Parasympathetic fibers:** Secretomotor to the parotid gland (via the otic ganglion). 2. **Sympathetic fibers:** To the sweat glands and blood vessels of the overlying skin. During surgery, these fibers are severed. During healing, the parasympathetic fibers mistakenly grow into the distal sheaths of the sympathetic fibers. Consequently, a stimulus intended for salivation (seeing or smelling food) results in localized **sweating and flushing** of the skin over the parotid area. **Why Other Options are Incorrect:** * **Lingual Nerve:** Provides sensory innervation to the anterior 2/3 of the tongue and carries taste (via chorda tympani). It is not involved in parotid innervation. * **Inferior Alveolar Nerve:** Supplies the mandibular teeth and the chin (mental nerve). It does not have a secretomotor role for the parotid. * **Nerve to Mylohyoid:** A branch of the inferior alveolar nerve that supplies the mylohyoid and the anterior belly of the digastric muscle. **Clinical Pearls for NEET-PG:** * **Diagnosis:** Confirmed by the **Minor’s Starch-Iodine Test** (the area turns blue-black upon sweating). * **Treatment:** Topical anticholinergics (Glycopyrrolate) or **Botulinum toxin** injections (most effective). * **Prevention:** Interposition of a barrier (e.g., SMAS flap or acellular dermal matrix) during parotidectomy.

Q: What is the most common site for minor salivary gland tumors?

Palate. **Explanation:** The **palate** (specifically the hard palate) is the most common site for minor salivary gland tumors, accounting for approximately **40–50%** of all cases. Minor salivary glands are distributed throughout the upper aerodigestive tract, but their highest density is found at the junction of the hard and soft palate. **Analysis of Options:** * **B. Palate (Correct):** Due to the high concentration of minor salivary tissue, the palate is the primary site. A key clinical feature of minor salivary gland tumors is that they are more likely to be **malignant** (approx. 50%) compared to parotid tumors (approx. 20%). * **A. Cheek (Buccal Mucosa):** While minor 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. Although rare, tumors here have an extremely high malignancy rate (80%). * **D. Tongue:** Tumors can occur at the base or lateral borders (associated with glands of Von Ebner), but the frequency is much lower than the palatal site. **High-Yield Clinical Pearls for NEET-PG:** 1. **Most common minor salivary gland tumor:** Adenoid Cystic Carcinoma (overall, though Pleomorphic Adenoma is the most common benign type). 2. **Rule of 80s (Salivary Glands):** 80% of tumors are in the Parotid; 80% of Parotid tumors are Pleomorphic Adenoma; 80% are in the superficial lobe. 3. **Malignancy Risk:** The smaller the gland, the higher the risk of malignancy (Sublingual > Submandibular > Parotid). 4. **Adenoid Cystic Carcinoma:** Characterized by **perineural invasion** and a "Swiss-cheese" appearance on histology.

Q: What is perimolysis?

Tooth wear due to gastric secretion. **Explanation:** **Perimolysis** (also known as dental erosion) refers to the irreversible loss of dental hard tissue due to a chemical process involving extrinsic or intrinsic acids, without bacterial involvement. 1. **Why Option A is Correct:** Perimolysis is specifically associated with **intrinsic acid**—namely, gastric hydrochloric acid (pH 1–2). When gastric contents enter the oral cavity, the acid chemically dissolves the hydroxyapatite crystals of the enamel. This is most commonly seen in patients with **GERD (Gastroesophageal Reflux Disease)** or eating disorders like **Bulimia Nervosa** (due to self-induced vomiting). The erosion typically affects the **palatal surfaces** of the maxillary teeth. 2. **Why the Other Options are Incorrect:** * **Option B (Bruxism):** This causes **Attrition**, which is tooth-to-tooth wear due to mechanical grinding or clenching. * **Option C (Dentifrices):** Tooth wear caused by external mechanical objects (like abrasive toothpastes or hard toothbrushes) is termed **Abrasion**. * **Option D (Peripheral blood cell destruction):** This is a hematological process (e.g., hemolysis) and is unrelated to dental pathology. **High-Yield Clinical Pearls for NEET-PG:** * **Patterns of Wear:** * *Attrition:* Incisal/occlusal surfaces. * *Abrasion:* Cervical/gingival margins. * *Perimolysis:* Palatal/lingual surfaces (classic sign of Bulimia). * **Sialadenosis:** Chronic, bilateral, non-inflammatory swelling of the parotid glands is often seen in bulimic patients alongside perimolysis. * **Management:** Treatment involves addressing the underlying gastric cause and using fluoride rinses to remineralize enamel; immediate brushing after acid exposure should be avoided as it accelerates wear.

Question 1

True regarding Warthin's tumor?

Accepted Answer

Shows a hot spot on technetium-99m scan

Answer

Most common tumor of minor salivary glands

Answer

Most common malignant tumor

Answer

Common in females

Question 2

A 45-year-old man presents with a small mass in his oral cavity. Physical examination reveals left facial nerve palsy and a firm, mobile, painless mass in the left parapharyngeal space. Biopsy of the oral cavity mass shows chondromyxoid stroma and epithelium. Which of the following best explains this mass?

Accepted Answer

The mass represents the most common salivary gland tumor.

Answer

Once excised, no recurrence occurs.

Answer

The mass represents a benign cystic tumor with germinal centers.

Answer

The mass represents the most common malignant tumor in the salivary glands.

Question 3

Which jaw cyst is premalignant?

Accepted Answer

Odontogenic keratocyst

Answer

Radicular cyst

Answer

Dental cyst

Answer

Dentigerous cyst

Question 4

A white persistent patch in the mouth most commonly indicates which of the following?

Accepted Answer

Streptococcal infection

Answer

Mucormycosis

Answer

Erythroplakia

Answer

None of the above

Question 5

Frey's syndrome is due to involvement of which nerve?

Accepted Answer

Auriculotemporal nerve

Answer

Lingual nerve

Answer

Inferior alveolar nerve

Answer

Nerve to mylohyoid

Question 6

Which of the following statements about salivary gland tumors is false?

Accepted Answer

The most common neoplasm of salivary glands in children is pleomorphic adenoma.

Answer

Mucoepidermoid carcinoma is the most common malignant tumor of salivary glands.

Answer

MRI is the best imaging investigation for salivary gland neoplasms.

Answer

FNAC is the best diagnostic modality for parotid swelling.

Question 7

What is the most common site for minor salivary gland tumors?

Accepted Answer

Palate

Answer

Cheek

Answer

Sublingual gland

Answer

Tongue

Question 8

What is perimolysis?

Accepted Answer

Tooth wear due to gastric secretion

Answer

Tooth wear due to bruxism

Answer

Tooth wear due to dentifrices

Answer

Peripheral blood cell destruction

Question 9

All of the following statements about lymphoepithelioma of the parotid gland are true, except:

Accepted Answer

Parotid gland is the most common site of lymphoepithelioma in the head and neck region

Answer

It is associated with EBV infection

Answer

It is highly radiosensitive

Answer

It is a type of squamous cell carcinoma

Question 10

All of the following are true about Mucoepidermoid carcinoma except -

Accepted Answer

Greater the mucin-producing cells, more malignant is the behavior

Answer

Invades the facial nerve

Answer

Behave like benign tumors in major salivary glands

Answer

Facial nerve preservation can be considered in low-grade tumors

Diseases of the Oral Cavity and Salivary Glands — MCQs

Diseases of the Oral Cavity and Salivary Glands — MCQs

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