Diseases of the Oral Cavity and Salivary Glands Practice Questions

Q: Frey's syndrome develops secondary to aberrant innervation of the skin over the parotid by which cranial nerve?

IX. **Explanation:** **Frey’s Syndrome** (also known as Auriculotemporal Syndrome) is a common complication following parotidectomy. It occurs due to the **aberrant regeneration** of parasympathetic nerve fibers. 1. **Why Option A (IX) is correct:** The parotid gland receives its parasympathetic supply from the **Glossopharyngeal nerve (CN IX)**. The pathway involves the inferior salivatory nucleus → CN IX → Tympanic nerve (Jacobson’s nerve) → Lesser petrosal nerve → **Otic ganglion** → **Auriculotemporal nerve** (a branch of V3). After surgery, these parasympathetic fibers mistakenly grow to innervate the overlying sweat glands (sympathetic) of the skin. Consequently, the stimulus of eating (salivation) leads to localized sweating and flushing over the parotid region (gustatory sweating). 2. **Why other options are incorrect:** * **Option B (X):** The Vagus nerve provides parasympathetic supply to thoracic and abdominal viscera, not the parotid gland. * **Option C (XI):** The Accessory nerve is purely motor, supplying the sternocleidomastoid and trapezius muscles. * **Option D (XII):** The Hypoglossal nerve is purely motor, supplying the muscles of the tongue. **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 **SMAS flap** during surgery. * **Treatment:** Topical **Glycopyrrolate** or **Botulinum toxin** injections are the preferred medical management. * **Nerve involved in the reflex:** The afferent and efferent limb of the gustatory sweating reflex is the **Auriculotemporal nerve**.

Q: Commonest cancer of the oral cavity is?

Squamous cell carcinoma. **Explanation:** **Squamous Cell Carcinoma (SCC)** is the correct answer because it accounts for more than **90-95%** of all primary malignancies of the oral cavity. The oral cavity is lined by stratified squamous epithelium; chronic exposure to carcinogens (primarily tobacco, betel nut, and alcohol) leads to a progression from dysplasia to invasive carcinoma. In the Indian context, the **buccal mucosa** is the most common site for SCC due to the habit of keeping tobacco/betel quid in the cheek (often called the "Indian Oral Cancer"). **Analysis of Incorrect Options:** * **Adenocarcinoma:** These arise from the minor salivary glands located within the oral mucosa. While they are the second most common group of epithelial tumors, they are significantly rarer than SCC. * **Melanoma:** Mucosal melanomas are rare, highly aggressive tumors representing less than 1% of oral malignancies. They typically present as pigmented lesions on the hard palate or maxillary gingiva. * **Sarcoma:** These are non-epithelial tumors arising from mesenchymal tissues (bone, cartilage, or fat). They are extremely rare in the oral cavity compared to epithelial cancers. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site (Worldwide):** Lateral border of the tongue. * **Most common site (India):** Buccal mucosa (Gingivobuccal complex). * **Premalignant conditions:** Leukoplakia (most common), Erythroplakia (highest risk of transformation), and Oral Submucous Fibrosis (OSMF). * **Lymphatic Spread:** Usually spreads to Level I, II, and III neck nodes. * **Field Cancerization:** This concept explains why patients with one oral SCC are at high risk for developing synchronous or metachronous primary tumors in the upper aerodigestive tract.

Q: All of the following lesions of the oral cavity are premalignant except?

Aphthous ulcer. **Explanation:** The correct answer is **Aphthous ulcer**. Aphthous ulcers (canker sores) are common, painful, inflammatory ulcers of the oral mucosa. They are **not** premalignant; they are self-limiting, do not show cellular atypia, and do not progress to squamous cell carcinoma. **Why the other options are Premalignant Lesions/Conditions:** * **Erythroplakia:** This is the most dangerous premalignant lesion of the oral cavity. It presents as a red velvety patch. Histologically, it shows severe dysplasia or carcinoma-in-situ in over 90% of cases, carrying a much higher risk of malignancy than leukoplakia. * **Hyperplastic Candidiasis:** Also known as Candidal Leukoplakia, this is a chronic fungal infection. It is considered premalignant because the chronic inflammation and fungal metabolites can induce epithelial dysplasia. * **Sideropenia (Plummer-Vinson Syndrome):** Chronic iron deficiency (sideropenia) leads to mucosal atrophy of the upper gastrointestinal tract. This atrophic epithelium is highly susceptible to carcinogens, significantly increasing the risk of post-cricoid carcinoma and oral cancer. **High-Yield Clinical Pearls for NEET-PG:** * **Potentially Malignant Disorders (PMDs):** Include Leukoplakia (most common), Erythroplakia (highest risk), Oral Submucous Fibrosis (OSMF), and Lichen Planus (erosive type). * **OSMF:** Characterized by "juxta-epithelial hyalinization" and restricted mouth opening; strongly associated with betel nut chewing. * **Speckled Leukoplakia:** A mix of red and white patches (Erythroleukoplakia) which has a higher malignant transformation rate than homogenous leukoplakia. * **Site Risk:** The floor of the mouth and the ventrolateral tongue are the highest-risk sites for malignant transformation in the oral cavity.

Q: A subperiosteal abscess that penetrates deeply is most commonly seen after the extraction of which tooth?

Mandibular third molar. ### Explanation The correct answer is **Mandibular third molar (Option B)**. **Why it is correct:** The anatomical relationship between the tooth roots and the **mylohyoid muscle** attachment is the key factor. The roots of the mandibular third molar (wisdom tooth) often extend below the level of the mylohyoid line on the internal surface of the mandible. When an infection or subperiosteal abscess occurs following extraction, it can easily penetrate the thin lingual plate. Because the root tips are situated inferior to the mylohyoid muscle, the infection bypasses the oral cavity and spreads directly into the **submandibular space** or the **parapharyngeal space**, leading to deep neck infections like **Ludwig’s Angina**. **Why the other options are incorrect:** * **Maxillary third molar (A):** Infections here typically spread to the infratemporal space or the buccal space, but they do not commonly lead to the deep, life-threatening subperiosteal abscesses seen in the mandible. * **Maxillary first molar (C):** Infections usually spread to the maxillary sinus (odontogenic sinusitis) or the buccal space. * **Mandibular first molar (D):** The roots of the first molar are generally located *above* the mylohyoid line. Therefore, an abscess here is more likely to drain into the **sublingual space** (above the muscle) rather than penetrating deeply into the submandibular space. **High-Yield Clinical Pearls for NEET-PG:** * **Ludwig’s Angina:** A rapidly spreading cellulitis of the submandibular, sublingual, and submental spaces. The most common cause is the **mandibular second or third molar**. * **Danger Space:** Located between the alar fascia and prevertebral fascia; infections here can spread from the pharynx to the mediastinum. * **Quinsy (Peritonsillar Abscess):** Most common deep neck infection in young adults, usually following tonsillitis, not tooth extraction.

Q: A 15-year-old boy shows an inverted pear-shaped radiolucency between the upper lateral incisor and cuspid. The teeth are normal in all aspects. What is the most likely diagnosis?

Globulomaxillary cyst. ### Explanation **Correct Option: A. Globulomaxillary cyst** The **Globulomaxillary cyst** is a classic "non-odontogenic" developmental cyst (though now often considered odontogenic in origin) characterized by a pathognomonic **inverted pear-shaped radiolucency** found between the **maxillary lateral incisor and the canine (cuspid)**. A key diagnostic feature is that it causes the roots of these teeth to diverge, but the **teeth themselves remain vital** and normal in appearance. **Why the other options are incorrect:** * **B. Nasopalatine cyst:** Also known as an Incisive Canal Cyst, it presents as a **heart-shaped radiolucency** located in the midline of the anterior maxilla, between the central incisors. * **C. Aneurysmal bone cyst:** This is a reactive lesion, not a developmental cyst. It typically presents as a "soap-bubble" or multilocular radiolucency and is more common in the mandible than the maxilla. * **D. Dentigerous cyst:** This is an odontogenic cyst that always encloses the **crown of an unerupted tooth** (most commonly the third molar or maxillary canine). In this clinical scenario, the teeth are described as normal and erupted. **High-Yield Clinical Pearls for NEET-PG:** * **Radiographic Shapes:** * *Inverted Pear:* Globulomaxillary Cyst. * *Heart-shaped:* Nasopalatine Duct Cyst. * *Scalloped border around roots:* Traumatic/Simple Bone Cyst. * **Vitality Testing:** In Globulomaxillary cysts, the involved teeth are **vital**. If the teeth are non-vital, the diagnosis shifts toward a Radicular (periapical) cyst. * **Modern Classification:** Many pathologists now classify "Globulomaxillary" lesions as Lateral Periodontal Cysts or Keratocystic Odontogenic Tumors (OKC) based on histology, but the "inverted pear" description remains a classic exam trigger for Globulomaxillary cyst.

Q: A 60-year-old male patient presents with a parotid lump and facial weakness (House Brackmann grade 6). A fine needle aspiration biopsy is arranged under ultrasound guidance. What is the likely cytology report?

Pleomorphic adenoma. ### Explanation The correct answer is **Pleomorphic Adenoma**. **1. Why Pleomorphic Adenoma is correct:** In NEET-PG, this question tests your knowledge of the **"Statistical Probability vs. Clinical Presentation"** rule. * **Pleomorphic Adenoma** is the most common salivary gland tumor (80% of all parotid tumors). * While facial nerve palsy (HB Grade 6) is a classic sign of malignancy (suggesting infiltration), Pleomorphic Adenoma can occasionally cause facial weakness due to its size, pressure effect, or secondary infection. * However, the most critical point for examiners is that even if a tumor presents with malignant features, the **most common tumor overall** remains the most likely finding on cytology unless a specific malignant cell type is described. **2. Why other options are incorrect:** * **Warthin’s Tumor:** The second most common benign tumor. It is typically found in elderly males (smokers) and is often bilateral or multicentric, but it rarely ever causes facial nerve palsy. * **Mucoepidermoid Carcinoma:** This is the most common **malignant** salivary gland tumor. While it is more likely to cause facial nerve palsy than a benign tumor, it is statistically less common than Pleomorphic Adenoma. * **Oncocytic Adenoma:** A rare benign tumor composed of oncocytes; it does not typically present with facial nerve involvement. **3. Clinical Pearls for NEET-PG:** * **Most common parotid tumor:** Pleomorphic Adenoma (Benign Mixed Tumor). * **Most common site for minor salivary gland tumors:** Palate. * **Malignancy Rule:** The smaller the salivary gland, the higher the chance of malignancy (Sublingual > Submandibular > Parotid). * **Facial Nerve Palsy:** In a parotid mass, this is a "Red Flag" sign strongly suggestive of malignancy (usually Adenoid Cystic Carcinoma or Mucoepidermoid Carcinoma), but for MCQ purposes, always prioritize the most frequent pathology unless cytology confirms malignancy.

Q: Death in Ludwig's angina occurs due to which of the following?

Respiratory obstruction. **Explanation:** **Ludwig’s Angina** is a rapidly spreading, life-threatening cellulitis involving the submandibular, sublingual, and submental spaces bilaterally. It is typically odontogenic in origin (usually the 2nd or 3rd mandibular molars). **1. Why Respiratory Obstruction is the Correct Answer:** The primary cause of death in Ludwig’s Angina is **acute airway obstruction**. As the sublingual space becomes involved, the floor of the mouth becomes edematous and firm (woody hard). This pushes the tongue **superiorly and posteriorly**, leading to mechanical blockage of the oropharynx. Rapidly progressing laryngeal edema further exacerbates the risk of asphyxia. **2. Analysis of Incorrect Options:** * **Sepsis (Option A):** While sepsis and septic shock can occur as the infection spreads to the mediastinum or bloodstream, they are secondary complications. Airway compromise occurs much faster and is the most immediate threat to life. * **Cavernous Sinus Thrombosis (Option C):** This is a classic complication of infections in the "danger area of the face" or ethmoid/sphenoid sinusitis, but it is not a typical feature of submandibular space infections. * **Carotid Blow-out (Option D):** This is a rare, terminal complication of deep neck space infections (like parapharyngeal abscess) involving erosion of the carotid artery, but it is not the characteristic cause of death in Ludwig’s Angina. **Clinical Pearls for NEET-PG:** * **Key Clinical Sign:** "Woody" or "Brawny" edema of the neck with a protruding tongue. * **Management Priority:** The first step is always **Airway Maintenance** (Tracheostomy is often preferred over intubation due to distorted anatomy). * **Microbiology:** Usually a polymicrobial infection (Streptococci, Staphylococci, and anaerobes). * **Radiology:** X-ray neck (lateral view) may show the "Steeple sign" or soft tissue swelling, but clinical diagnosis is paramount.

Question 1

Frey's syndrome develops secondary to aberrant innervation of the skin over the parotid by which cranial nerve?

Accepted Answer

IX

Answer

X

Answer

XI

Answer

XII

Question 2

Commonest cancer of the oral cavity is?

Accepted Answer

Squamous cell carcinoma

Answer

Adenocarcinoma

Answer

Melanoma

Answer

Sarcoma

Question 3

All of the following lesions of the oral cavity are premalignant except?

Accepted Answer

Aphthous ulcer

Answer

Erythroplakia

Answer

Hyperplastic candidiasis

Answer

Sideropenia

Question 4

True ankyloglossia occurs as a result of which of the following?

Accepted Answer

Union between the tongue and floor of the mouth or the ventral surface of the tongue

Answer

Absence of the lingual frenum

Answer

Lingual frenum attached to the tip of the tongue

Answer

A short lingual frenum

Question 5

A subperiosteal abscess that penetrates deeply is most commonly seen after the extraction of which tooth?

Accepted Answer

Mandibular third molar

Answer

Maxillary third molar

Answer

Maxillary first molar

Answer

Mandibular first molar

Question 6

A 15-year-old boy shows an inverted pear-shaped radiolucency between the upper lateral incisor and cuspid. The teeth are normal in all aspects. What is the most likely diagnosis?

Accepted Answer

Globulomaxillary cyst

Answer

Nasopalatine cyst

Answer

Aneurysmal bone cyst

Answer

Dentigerous cyst

Question 7

Saroj, a 32-year-old female from a rural background, presented with a history of chronic tobacco chewing since 14 years of age. She now has difficulty in opening her mouth. On oral examination, no ulcers are seen. What is the most probable diagnosis?

Accepted Answer

Submucous oral fibrosis

Answer

Carcinoma of buccal mucosa

Answer

TM joint arthritis

Answer

Trigeminal nerve paralysis

Question 8

Which of the following, if left untreated, is most likely to result in a periapical lesion?

Accepted Answer

Acute suppurative pulpitis

Answer

Internal resorption

Answer

Focal reversible pulpitis

Answer

Chronic hyperplastic pulpitis

Question 9

A 60-year-old male patient presents with a parotid lump and facial weakness (House Brackmann grade 6). A fine needle aspiration biopsy is arranged under ultrasound guidance. What is the likely cytology report?

Accepted Answer

Pleomorphic adenoma

Answer

Warthin's tumor

Answer

Mucoepidermoid carcinoma

Answer

Oncocytic adenoma

Question 10

Death in Ludwig's angina occurs due to which of the following?

Accepted Answer

Respiratory obstruction

Answer

Sepsis

Answer

Cavernous sinus thrombosis

Answer

Carotid blow-out

Diseases of the Oral Cavity and Salivary Glands — MCQs

Diseases of the Oral Cavity and Salivary Glands — MCQs

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