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 81: A 36-year-old male patient presents with swelling in the submandibular region, elevated tongue, and dysphagia. He has a high fever, and intraoral examination reveals a grossly destructed lower first molar. What is the likely cause of the high fever associated with this patient's condition?

A. Septicemia
B. Reduced immunity
C. Severity of infection
D. All of the above (Correct Answer)

Explanation: ### **Explanation** The clinical presentation of submandibular swelling, an elevated tongue (due to displacement of the floor of the mouth), dysphagia, and a decayed lower molar is a classic description of **Ludwig’s Angina**. This is a rapidly spreading, life-threatening cellulitis of the submandibular, sublingual, and submental spaces. **Why "All of the above" is the correct answer:** 1. **Severity of Infection:** Ludwig’s Angina is a "brawny" cellulitis that spreads by continuity rather than lymphatics. The aggressive nature of the mixed aerobic-anaerobic infection (often *Streptococcus* and *Staphylococcus*) triggers a potent systemic inflammatory response, leading to high-grade fever. 2. **Septicemia:** Due to the high vascularity of the head and neck, bacteria and their toxins can easily enter the bloodstream from the submandibular space, leading to sepsis and systemic toxicity. 3. **Reduced Immunity:** While Ludwig’s Angina can occur in healthy individuals, it is significantly more common and severe in immunocompromised patients (e.g., those with Diabetes Mellitus). Reduced immunity allows the odontogenic infection to bypass local defenses and manifest with severe systemic symptoms like high fever. **Analysis of Options:** * **Options A, B, and C** are all individual contributing factors. In the context of a systemic response to a deep neck space infection, they are interrelated. Therefore, "All of the above" is the most comprehensive choice. ### **Clinical Pearls for NEET-PG** * **Source of Infection:** The most common cause is a dental infection, typically the **lower 2nd or 3rd molar** (as their roots lie below the mylohyoid line). * **Key Sign:** The hallmark is **woody/brawny edema** of the neck and **elevation of the tongue**, which poses a high risk of airway obstruction. * **Management:** The priority is **Airway Maintenance** (often requiring tracheostomy), followed by IV antibiotics and surgical incision and drainage (I&D). * **Most Common Organism:** *Streptococcus viridans*.

Question 82: Which of the following is not always a true odontogenic infection?

A. Periapical abscess
B. Periodontal abscess
C. Maxillary sinusitis (Correct Answer)
D. None of the above

Explanation: **Explanation:** The core concept here is the distinction between infections that **originate** from the teeth (odontogenic) and those that can have multiple etiologies. **Why Maxillary Sinusitis is the correct answer:** While maxillary sinusitis can be odontogenic in origin (approximately 10–12% of cases, usually due to periapical infections of the maxillary molars or premolars), it is **not always** odontogenic. The vast majority of maxillary sinusitis cases are **rhinogenic**, following viral upper respiratory tract infections or allergic rhinitis. Therefore, it is the only option that is not inherently or "always" a true odontogenic infection. **Analysis of incorrect options:** * **Periapical Abscess:** This is a true odontogenic infection. It occurs at the apex of the tooth root, typically following dental caries that lead to pulp necrosis and subsequent infection of the periapical tissues. * **Periodontal Abscess:** This is also a true odontogenic infection. It originates in the supporting structures of the teeth (the periodontium), often due to deep periodontal pockets or food impaction. **High-Yield Clinical Pearls for NEET-PG:** * **Odontogenic Sinusitis:** Suspect this if the sinusitis is **unilateral** and associated with a **foul-smelling (cacosmia)** discharge. * **First Molar Rule:** The maxillary first molar is the tooth most commonly associated with odontogenic maxillary sinusitis due to the proximity of its roots to the sinus floor. * **Ludwig’s Angina:** A life-threatening cellulitis of the submandibular space, most commonly caused by an odontogenic infection of the **2nd and 3rd mandibular molars**.

Question 83: What is the most common salivary gland tumor in children?

A. Lymphoma
B. Adenoid cystic carcinoma
C. Pleomorphic adenoma
D. Mucoepidermoid carcinoma (Correct Answer)

Explanation: **Explanation:** The distribution of salivary gland tumors in children differs significantly from adults. While salivary gland neoplasms are rare in the pediatric population, a higher percentage of these tumors (approximately 50%) are malignant compared to adults (where 80% are benign). **1. Why Mucoepidermoid Carcinoma is correct:** Mucoepidermoid carcinoma is the **most common malignant salivary gland tumor** in both children and adults. However, specifically in the pediatric age group, it is also the **most common salivary gland tumor overall**, surpassing benign options. It most frequently involves the parotid gland and typically presents as a painless, slow-growing mass. **2. Analysis of Incorrect Options:** * **Pleomorphic Adenoma (Option C):** This is the most common salivary gland tumor in **adults** and the most common **benign** tumor in children. However, in pediatric statistics, Mucoepidermoid carcinoma occurs with slightly higher frequency overall. * **Adenoid Cystic Carcinoma (Option B):** This is the second most common malignant salivary gland tumor in children. It is known for its "Swiss cheese" appearance on histology and its tendency for perineural invasion, but it is less common than Mucoepidermoid carcinoma. * **Lymphoma (Option A):** While lymphomas can involve the intra-parotid lymph nodes, they are not primary epithelial salivary gland tumors and are much rarer in this anatomical site compared to Mucoepidermoid carcinoma. **High-Yield Clinical Pearls for NEET-PG:** * **Most common benign tumor (Children & Adults):** Pleomorphic Adenoma. * **Most common malignant tumor (Children & Adults):** Mucoepidermoid Carcinoma. * **Most common tumor overall in Children:** Mucoepidermoid Carcinoma. * **Rule of Thumb:** The smaller the salivary gland, the higher the chance of malignancy (e.g., sublingual gland tumors are ~80% malignant). * **Hemangioma:** The most common **benign non-epithelial** lesion of the parotid in infants (often presenting as a vascular parotid swelling).

Question 84: In MPDS (Masticatory Muscle Pain Dysfunction Syndrome), which muscle is most commonly involved?

A. Lateral pterygoid (Correct Answer)
B. Masseter
C. Temporalis
D. Medial pterygoid

Explanation: **Explanation:** **Masticatory Muscle Pain Dysfunction Syndrome (MPDS)**, also known as Temporomandibular Joint Dysfunction Syndrome, is a psychophysiological disorder characterized by pain, muscle tenderness, and restricted jaw movement. **Why Lateral Pterygoid is the Correct Answer:** The **lateral pterygoid** is the most frequently involved muscle in MPDS. This is primarily due to its unique anatomical role: it is the only muscle of mastication responsible for **opening the mouth** (depression of the mandible) and protrusion. In cases of stress-induced bruxism or malocclusion, this muscle undergoes constant fatigue and spasm. Spasm of the lateral pterygoid leads to the characteristic "clicking" sound of the TMJ and trismus (limited mouth opening). **Analysis of Incorrect Options:** * **Masseter:** While the masseter is a powerful elevator of the jaw and often shows tenderness in chronic cases, it is typically involved secondary to the lateral pterygoid. * **Temporalis:** This muscle is often associated with "tension-type headaches" in MPDS patients, but it is not the primary or most common site of initial muscle dysfunction. * **Medial Pterygoid:** Like the masseter, this is an elevator muscle. While it can be involved in internal derangements, it is less frequently the primary source of pain compared to its lateral counterpart. **High-Yield Clinical Pearls for NEET-PG:** * **Classic Triad of MPDS:** Pain, clicking/popping sounds in the TMJ, and limitation of jaw movement. * **Etiology:** Often linked to psychological stress, anxiety, and parafunctional habits (bruxism). * **Management:** Conservative treatment is the first line, including reassurance, soft diet, NSAIDs, and muscle relaxants. Occlusal splints (night guards) are highly effective. * **Differential Diagnosis:** Must be distinguished from Costen’s Syndrome (an older term for TMJ neuralgia).

Question 85: Adenomatoid odontogenic tumour is most commonly found in which location?

A. Anterior mandible
B. Posterior maxilla
C. Anterior maxilla (Correct Answer)
D. Ramus of mandible

Explanation: **Explanation:** Adenomatoid Odontogenic Tumour (AOT) is a benign, slow-growing epithelial odontogenic lesion. It is often referred to as the **"Two-Thirds Tumor"** because approximately 2/3rd of cases occur in the maxilla, 2/3rd occur in young females (teenagers), and 2/3rd are associated with an impacted tooth (most commonly the maxillary canine). **1. Why Anterior Maxilla is Correct:** The most frequent site for AOT is the **anterior maxilla** (incisor-canine region). It typically presents as a well-circumscribed radiolucency surrounding the crown and part of the root of an unerupted tooth, mimicking a dentigerous cyst. However, unlike a dentigerous cyst, AOT often extends apically beyond the cemento-enamel junction. **2. Analysis of Incorrect Options:** * **Anterior mandible:** While AOT can occur here, it is significantly less common than the maxillary site. * **Posterior maxilla:** AOT has a strong predilection for the anterior segments of the jaws; posterior involvement is rare. * **Ramus of mandible:** This is a classic site for **Ameloblastoma** or **Odontogenic Keratocyst (OKC)**, but not for AOT. **3. Clinical Pearls for NEET-PG:** * **Radiological Appearance:** Often shows "snowflake" or "driven-snow" calcifications within the radiolucency (intralesional radiopacities). * **Histopathology:** Characterized by duct-like structures lined by cuboidal or columnar epithelium and whorled masses of epithelial cells (Rosette pattern). * **Treatment:** Conservative surgical enucleation; recurrence is extremely rare. * **Key Association:** Always remember the association with the **impacted maxillary canine**.

Question 86: A known HIV-infected patient presents with a non-tender parotid gland swelling. What is the most likely diagnosis?

A. B-cell non-Hodgkin's lymphoma
B. Lymphoepithelial cysts (Correct Answer)
C. Sialectasia
D. Parotid abscess

Explanation: ### Explanation **Correct Answer: B. Lymphoepithelial cysts** **Medical Concept:** In HIV-positive patients, the parotid gland is a common site for **Benign Lymphoepithelial Cysts (BLEC)**. These cysts are part of the "HIV-associated salivary gland disease" (HIV-SGD) spectrum. The pathogenesis involves the proliferation of lymphoid tissue within the parotid gland (which naturally contains intra-nodal salivary duct inclusions), leading to ductal obstruction and subsequent cystic dilatation. Clinically, they present as **painless, soft, often bilateral** parotid swellings. **Analysis of Incorrect Options:** * **A. B-cell non-Hodgkin's lymphoma:** While HIV patients have a significantly higher risk of developing NHL, it typically presents as a rapidly enlarging, firm, or hard mass, often associated with systemic "B" symptoms (fever, weight loss). BLEC is statistically more common as a primary cause of parotid swelling in this demographic. * **C. Sialectasia:** This refers to the dilation of the salivary ducts, usually seen in chronic sialadenitis or Sjögren’s syndrome. While it causes swelling, it is not specifically pathognomonic for HIV in the way lymphoepithelial cysts are. * **D. Parotid abscess:** An abscess presents with acute, **exquisitely tender**, erythematous swelling accompanied by fever and purulent discharge from Stensen’s duct. This contradicts the "non-tender" presentation in the question. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnostic Gold Standard:** Contrast-Enhanced CT (CECT) or MRI shows characteristic **multiple, thin-walled, fluid-filled cysts** within the parotid glands. * **Bilateralism:** BLEC is frequently bilateral, which is a strong clinical clue for HIV-associated pathology. * **Management:** Highly Active Antiretroviral Therapy (HAART) often reduces the size of these cysts. Aspiration or surgical excision is reserved for cosmetic concerns or pressure symptoms. * **Association:** If you see "bilateral parotid swelling + cervical lymphadenopathy" in an HIV patient, think Lymphoepithelial Cysts first.

Question 87: A 60-year-old man presents with an ulcer on the lateral margin of his tongue, also complaining of ear pain. What is the most probable diagnosis?

A. Dental ulcer
B. Carcinomatous ulcer (Correct Answer)
C. Tuberculosis ulcer
D. Syphilitic ulcer

Explanation: ### Explanation The correct diagnosis is **Carcinomatous ulcer** (Squamous Cell Carcinoma of the tongue). **1. Why it is correct:** In an elderly patient (60 years), a chronic ulcer on the **lateral margin of the tongue** is highly suspicious of malignancy. The key clinical feature here is the **referred otalgia (ear pain)**. The tongue is supplied by the lingual nerve (a branch of the mandibular nerve, V3). Malignant infiltration of the lingual nerve causes pain that is referred to the ear via the **auriculotemporal nerve** (also a branch of V3). This "referred pain" is a classic red flag for base of tongue or lateral tongue carcinoma. **2. Why other options are incorrect:** * **Dental ulcer:** These are usually acute, associated with a sharp tooth or ill-fitting denture, and typically heal once the source of trauma is removed. They rarely cause referred otalgia unless severely infected. * **Tuberculosis ulcer:** These are typically **exquisitely painful**, shallow, with undermined edges, and usually occur on the tip of the tongue in patients with active pulmonary TB. * **Syphilitic ulcer:** Primary syphilis (chancre) is painless and usually on the tip; tertiary syphilis (gumma) occurs on the **dorsum** of the tongue in the midline, not the lateral margin. **3. NEET-PG High-Yield Pearls:** * **Most common site** for oral cavity cancer: Lower lip (globally), but in India, it is the **buccal mucosa** (due to tobacco chewing). * **Most common site for tongue cancer:** Lateral border of the anterior two-thirds. * **Lymphatic spread:** Tongue tip drains to Submental nodes (Level Ia); Lateral tongue drains to Submandibular (Level Ib) and then to Jugulodigastric nodes. * **Trotter’s Triad** (for Nasopharyngeal Ca) also involves referred otalgia, but the tongue ulcer specifically points to V3 involvement.

Question 88: Which of the following are premalignant lesions?

A. Submucous fibrosis
B. Leukoplakia
C. Erythroplakia
D. All of the above (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. All of the above**. In the context of Oral Oncology, a **premalignant lesion** (or potentially malignant disorder) is a morphologically altered tissue in which cancer is more likely to occur than in its normal counterpart. 1. **Leukoplakia:** Defined by the 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. While most are benign, the risk of malignant transformation is approximately 3–5%. 2. **Erythroplakia:** This presents as a fiery red, velvety patch. Although less common than leukoplakia, it has the **highest malignant potential** (over 50% show transformation or are already carcinoma in situ at the time of biopsy). 3. **Oral Submucous Fibrosis (OSMF):** A chronic, progressive condition characterized by juxta-epithelial inflammatory reaction followed by fibroelastic change of the lamina propria. It is strongly associated with **areca nut (betel nut)** chewing and carries a significant risk of transformation into Squamous Cell Carcinoma (SCC). **Clinical Pearls for NEET-PG:** * **Highest Malignant Potential:** Erythroplakia > OSMF > Leukoplakia. * **Speckled Leukoplakia (Erythroleukoplakia):** A mixed red-and-white lesion that carries a higher risk of malignancy than homogenous leukoplakia. * **OSMF Hallmark:** "Trismus" or restricted mouth opening due to vertical fibrous bands, often involving the buccal mucosa and soft palate. * **Biopsy Rule:** Any suspicious oral lesion persisting for more than 2 weeks despite removing local irritants must undergo biopsy to rule out malignancy.

Question 89: A cyst arising from an unerupted permanent tooth is termed:

A. Dentigerous cyst (Correct Answer)
B. Epulis
C. Odontogenic keratocyst
D. None of the above

Explanation: ### Explanation **Correct Answer: A. Dentigerous cyst** A **Dentigerous cyst** (also known as a follicular cyst) is an odontogenic cyst that develops from the accumulation of fluid between the reduced enamel epithelium and the crown of an **unerupted or impacted tooth**. * **Pathophysiology:** It originates at the cemento-enamel junction (CEJ). As the cyst grows, it encloses the crown of the tooth while the root remains outside the cyst sac. * **Common Site:** The most frequently involved tooth is the **mandibular third molar**, followed by the maxillary canine. * **Radiology:** It typically appears as a well-defined, unilocular radiolucency surrounding the crown of an unerupted tooth. **Why other options are incorrect:** * **B. Epulis:** This is a non-specific clinical term for any tumor-like gingival swelling (e.g., fibrous epulis, pregnancy tumor). It is a soft tissue lesion, not a bony cyst associated with unerupted teeth. * **C. Odontogenic Keratocyst (OKC):** While also an odontogenic cyst, it arises from the **dental lamina** rather than the follicle of an unerupted tooth. It is known for its aggressive behavior, high recurrence rate, and association with **Gorlin-Goltz syndrome**. Unlike dentigerous cysts, OKCs often expand in an anteroposterior direction within the marrow. **High-Yield Clinical Pearls for NEET-PG:** * **Most common odontogenic cyst:** Radicular cyst (associated with a non-vital/carious tooth). * **Most common developmental odontogenic cyst:** Dentigerous cyst. * **Radiological sign:** "Snow-plow" effect (displacement of adjacent teeth). * **Complications:** If left untreated, a dentigerous cyst can transform into an **Ameloblastoma** or, rarely, Squamous Cell Carcinoma. * **Treatment:** Enucleation and extraction of the involved tooth.

Question 90: Which of the following head and neck tumors has the worst prognosis?

A. Adenoid cystic carcinoma (Correct Answer)
B. Acinic cell carcinoma
C. Cystadenolymphoma
D. Mucoepidermoid carcinoma

Explanation: **Explanation:** The prognosis of salivary gland tumors depends on their histological grade, growth pattern, and tendency for local or distant spread. **Why Adenoid Cystic Carcinoma (ACC) is the correct answer:** Among the options provided, **Adenoid Cystic Carcinoma** is notorious for its aggressive biological behavior. While it is often slow-growing, it has a hallmark characteristic of **perineural invasion** (creeping along nerves), making complete surgical resection difficult and leading to high rates of local recurrence. Most importantly, it has a high propensity for **late distant metastasis** (most commonly to the lungs), which can occur even decades after initial treatment, resulting in a poor long-term survival rate. **Analysis of Incorrect Options:** * **Acinic Cell Carcinoma:** This is generally considered a low-grade malignancy with a relatively favorable prognosis and low metastatic potential compared to ACC. * **Cystadenolymphoma (Warthin’s Tumor):** This is a **benign** salivary gland tumor (typically involving the parotid). It has an excellent prognosis as it does not metastasize. * **Mucoepidermoid Carcinoma:** The prognosis here is highly variable depending on the grade. While high-grade variants are aggressive, the overall group includes many low-grade cases that have a much better prognosis than ACC. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site for ACC:** Submandibular gland and minor salivary glands (palate). * **Histological appearance:** Classic "Swiss-cheese" or cribriform pattern. * **Nerve Involvement:** ACC is the most common tumor to cause facial nerve palsy in the parotid gland. * **Warthin’s Tumor:** Associated with smoking, often bilateral/multicentric, and shows "Hot spots" on Technetium-99m pertechnetate scan.

Practice by Chapter

Stomatitis

Practice Questions

Oral Ulcers

Practice Questions

Oral Leukoplakia

Practice Questions

Oral Cancers

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Sialadenitis

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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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