Diseases of the Oral Cavity and Salivary Glands Practice Questions

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.

Q: All of the following are true about Ranula except:

Premalignant. **Explanation:** A **Ranula** is a clinical term used to describe a translucent, bluish, fluctuant swelling found specifically on the **floor of the mouth**. It is caused by the extravasation or retention of mucus from the **sublingual salivary gland**. 1. **Why "Premalignant" is the correct (False) statement:** A ranula is a purely benign, reactive, or obstructive inflammatory lesion. It is **not premalignant** and has no potential for neoplastic transformation. Any suspicion of malignancy in a floor-of-the-mouth swelling should lead to a differential diagnosis of a salivary gland tumor (like Mucoepidermoid carcinoma), but the ranula itself is benign. 2. **Analysis of other options:** * **Asymptomatic (Option A):** Most ranulas are painless and slow-growing. They typically only cause symptoms if they become large enough to interfere with speech, swallowing, or mastication. * **Retention Cyst (Option B):** While many ranulas are "extravasation pseudocysts" (lacking an epithelial lining), they are classically categorized under the umbrella of **mucous retention phenomena** resulting from ductal obstruction or trauma to the sublingual gland. * **Floor of the Mouth (Option D):** This is the classic anatomical location. It arises lateral to the midline, distinguishing it from a dermoid cyst which is typically midline. **High-Yield Clinical Pearls for NEET-PG:** * **Plunging Ranula:** Occurs when the mucus extravasates through or around the **mylohyoid muscle**, presenting as a swelling in the submandibular neck region. * **Appearance:** Often described as "frog’s belly" appearance due to its translucent blue color. * **Treatment of Choice:** Surgical excision of the ranula along with the **offending sublingual gland**. Marsupialization is an alternative but has a higher recurrence rate.

Question 1

Which jaw cyst is premalignant?

Accepted Answer

Odontogenic keratocyst

Answer

Radicular cyst

Answer

Dental cyst

Answer

Dentigerous cyst

Question 2

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 3

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 4

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 5

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

Accepted Answer

Palate

Answer

Cheek

Answer

Sublingual gland

Answer

Tongue

Question 6

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 7

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 8

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

Question 9

A 40-year-old female presented with bilateral parotid gland enlargement, dry eyes, dry mouth, chronic non-productive cough, and shortness of breath. On examination, hepatosplenomegaly was noted. CT scan of the chest and salivary gland biopsy were performed. Which of the following interleukins is involved in the pathogenesis of this disease?

Accepted Answer

IL-18

Answer

IL-17

Answer

IL-15

Answer

IL-10

Question 10

All of the following are true about Ranula except:

Accepted Answer

Premalignant

Answer

Asymptomatic

Answer

Retention cyst

Answer

Occurs commonly on the floor of the mouth

Diseases of the Oral Cavity and Salivary Glands — MCQs

Diseases of the Oral Cavity and Salivary Glands — MCQs

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