Diseases of the Oral Cavity and Salivary Glands Practice Questions

Q: Which of the following develops from an unerupted tooth?

Dentigerous cyst. ### Explanation **Correct Answer: B. Dentigerous cyst** #### Why Dentigerous Cyst is Correct: A **Dentigerous cyst** (also known as a follicular cyst) is an odontogenic cyst that originates from the **reduced enamel epithelium** surrounding the crown of an **un-erupted or impacted tooth**. It is the second most common odontogenic cyst after the radicular cyst. * **Pathophysiology:** Fluid accumulates between the reduced enamel epithelium and the tooth crown, causing the cyst to attach at the **cemento-enamel junction (CEJ)**. * **Common Site:** It most frequently involves the **mandibular third molar**, followed by the maxillary canine. #### Why Other Options are Incorrect: * **A. Dental Cyst (Radicular Cyst):** This is an inflammatory cyst that develops at the apex of a **non-vital, erupted tooth**. It arises from the epithelial rests of Malassez in the periodontal ligament due to pulp necrosis or dental caries. It does *not* involve an unerupted tooth. * **C & D:** Since the mechanisms of formation for dental and dentigerous cysts are distinct (inflammatory vs. developmental), only Option B is correct. #### High-Yield Clinical Pearls for NEET-PG: * **Radiological Appearance:** Dentigerous cysts appear as a well-defined, unilocular radiolucency surrounding the crown of an impacted tooth. * **Most Common Odontogenic Cyst:** Radicular (Dental) cyst. * **Most Common Developmental Odontogenic Cyst:** Dentigerous cyst. * **Potential Complications:** If left untreated, a dentigerous cyst can lead to pathological fractures or transform into an **Ameloblastoma** or Squamous Cell Carcinoma. * **Treatment:** Surgical enucleation and extraction of the associated impacted tooth.

Q: A 16-year-old female patient presents with a one-week history of small ulcers on her cheeks and tongue. On general examination, a mild rise in temperature is noted. Oral examination reveals multiple ulcers on the buccal and labial mucosa. She also reports that she has her board exams in one week. What is the likely diagnosis?

Minor aphthous ulcers. **Explanation:** The clinical presentation of multiple small, painful ulcers on the non-keratinized mucosa (buccal and labial) in a young patient, triggered by stress (upcoming exams), is classic for **Minor Aphthous Ulcers** (Canker sores). These are the most common type of recurrent aphthous stomatitis (RAS), typically measuring less than 1 cm and healing without scarring within 7–10 days. A mild prodromal fever is occasionally noted. **Analysis of Options:** * **Minor Aphthous Ulcers (Correct):** Characteristically occur on mobile, non-keratinized mucosa. Stress is a well-documented precipitating factor. * **Bullous Pemphigoid:** An autoimmune blistering disease primarily affecting the skin of the elderly. Oral involvement is rare (unlike Pemphigus Vulgaris) and would present as large, ruptured bullae rather than small, multiple ulcers in a teenager. * **Traumatic Ulcer:** Usually presents as a single, large, painful ulcer with an identifiable cause (e.g., a sharp tooth or dental appliance). It does not typically present with multiple lesions or systemic symptoms like fever. * **Tuberculoid Ulcer:** Typically presents as a chronic, painless, "undermined" ulcer, often on the dorsum of the tongue. It is usually secondary to pulmonary TB and lacks the acute, stress-related onset seen here. **High-Yield Clinical Pearls for NEET-PG:** * **Major Aphthous Ulcers (Sutton’s Disease):** >1 cm, deeper, very painful, and heal **with scarring**. * **Herpetiform Ulcers:** Multiple crops of tiny (1-2 mm) ulcers that may coalesce; not related to the Herpes virus despite the name. * **Treatment:** Primarily symptomatic (topical steroids like triamcinolone acetonide, topical anesthetics). * **Associations:** Rule out Behcet’s syndrome if oral ulcers are associated with genital ulcers and uveitis.

Q: Which stain is used to identify premalignant lesions of the oral cavity?

Toluidine blue. **Explanation:** **Toluidine Blue (Option A)** is a basic metachromatic thiazine dye that has a high affinity for acidic tissue components, specifically **nucleic acids**. Malignant and premalignant cells (dysplasia/carcinoma-in-situ) exhibit increased DNA synthesis, rapid cell division, and a higher nuclear-to-cytoplasmic ratio compared to normal cells. When applied topically to the oral mucosa, the dye is selectively retained in these areas of high DNA content, staining them deep blue. This is a vital staining technique used as a screening tool to demarcate biopsy sites and identify "occult" lesions not easily visible to the naked eye. **Analysis of Incorrect Options:** * **Malachite Green (Option B):** Primarily used as a biological stain for spores and in aquaculture as a fungicide; it has no clinical role in screening oral malignancy. * **Potassium Iodide (Option C):** Often used in the management of hyperthyroidism (Lugol’s iodine) or as an expectorant, but not as a diagnostic stain for oral lesions. * **Iodine (Option D):** While **Schiller’s test** (using Lugol’s iodine) is used in the cervix to identify dysplasia (where abnormal cells *fail* to take up the stain due to lack of glycogen), it is not the standard primary stain for oral premalignancy. **Clinical Pearls for NEET-PG:** * **False Positives:** Toluidine blue can stain inflammatory conditions (e.g., ulcers) because of the presence of inflammatory cells and debris. * **False Negatives:** Highly keratinized lesions (Leukoplakia) may not take up the stain well as the keratin acts as a barrier. * **Gold Standard:** Remember that vital staining is only a screening tool; **Incisional Biopsy** remains the definitive gold standard for diagnosing oral cancer.

Q: Which odontogenic tumor, when treated with simple curettage, is most likely to recur?

Odontogenic myxoma. **Explanation:** The correct answer is **Odontogenic Myxoma**. **1. Why Odontogenic Myxoma is correct:** Odontogenic myxoma is a benign but **locally aggressive** mesenchymal tumor. Its hallmark characteristic is its **gelatinous, non-encapsulated consistency** and a "loose" myxomatous stroma. Because it lacks a capsule, the tumor cells easily infiltrate the surrounding trabecular bone beyond the visible margins of the lesion. Simple curettage often leaves behind microscopic remnants, leading to a high recurrence rate (up to 25%). Therefore, the preferred treatment is wide local excision or resection with clear margins. **2. Why the other options are incorrect:** * **Complex and Compound Odontomas:** These are considered **hamartomas** rather than true neoplasms. They are well-circumscribed, encapsulated, and consist of mature dental tissues. Simple surgical enucleation or curettage is curative, and recurrence is extremely rare. * **Ameloblastic Fibroma:** This is a true mixed odontogenic tumor typically seen in younger patients. While it requires monitoring, it is generally well-demarcated and responds well to conservative surgical excision/enucleation compared to the infiltrative nature of a myxoma. **3. Clinical Pearls for NEET-PG:** * **Radiological Appearance:** Odontogenic myxoma typically presents as a multilocular radiolucency with a **"soap bubble," "honeycomb," or "tennis racket"** (straight septations) appearance. * **Histology:** Look for stellate and spindle-shaped cells in an abundant mucoid/myxomatous extracellular matrix (resembling the dental papilla). * **Age/Site:** Most common in the 2nd–3rd decades; the mandible is affected more frequently than the maxilla.

Q: All of the following are true about mucoepidermoid carcinoma except?

Usually causes facial paralysis.. **Explanation:** Mucoepidermoid carcinoma (MEC) is the most common malignant tumor of the salivary glands. The correct answer is **C** because facial nerve paralysis is **uncommon** in MEC, occurring in only about 10–15% of cases. Facial nerve involvement is typically a feature of high-grade malignancies or advanced stages; most MECs are low-grade and present as slow-growing, painless masses. **Analysis of Options:** * **Option A:** MEC is indeed the most common **radiation-induced** salivary gland neoplasm, often appearing years after exposure to ionizing radiation. * **Option B:** It is the most common **malignant** salivary gland tumor in both children and adults. (Note: Pleomorphic adenoma is the most common *benign* tumor in children). * **Option D:** While MEC can be low, intermediate, or high-grade, it tends to be **more aggressive and poorly differentiated in adults** compared to the pediatric population, where low-grade variants predominate. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Parotid gland (overall), but it is also the most common malignancy of the minor salivary glands (especially the palate). * **Histology:** Characterized by a mixture of three cell types: **Mucin-producing cells**, **Epidermoid (squamous) cells**, and **Intermediate cells**. * **Staining:** Mucicarmine stain is used to identify the intracellular mucin. * **Grading:** The prognosis depends heavily on the histological grade rather than just the TNM stage. Low-grade tumors have a 5-year survival rate of >90%.

Q: Perforation of the palate is seen with which of the following conditions?

Tertiary syphilis. **Explanation:** **Tertiary Syphilis (Correct Answer):** The hallmark lesion of tertiary syphilis is the **Gumma**, a chronic granulomatous lesion characterized by endarteritis obliterans. When a gumma involves the hard palate, it leads to localized ischemia and necrosis of the underlying bone, eventually causing a midline, painless **perforation of the palate**. This creates an oronasal communication, leading to nasal regurgitation of food and hypernasal speech. **Incorrect Options:** * **Minor Aphthous Ulcers:** These are small ( 10mm), deeper, and more painful than minor ulcers, they typically involve the soft tissues (lips, soft palate, fauces). Although they may heal with scarring, they do not cause full-thickness bony perforation of the hard palate. **High-Yield Clinical Pearls for NEET-PG:** * **Midline Perforation:** Always think of **Tertiary Syphilis** or **Wegener’s Granulomatosis** (Granulomatosis with Polyangiitis). * **Lateral Perforation:** More commonly associated with **Malignancy** (e.g., Squamous cell carcinoma of the maxillary sinus or palate) or **Mucormycosis** in immunocompromised patients. * **Cocaine Abuse:** Chronic intranasal cocaine use is a common non-infectious cause of midline palatal perforation due to intense vasoconstriction. * **Congenital Syphilis Triad (Hutchinson’s):** Hutchinson’s teeth, Interstitial keratitis, and Eighth nerve deafness.

Q: Intraoral pleomorphic adenoma most commonly occurs in which location?

Palate. **Explanation:** **Pleomorphic Adenoma (Benign Mixed Tumor)** is the most common salivary gland tumor overall. While it most frequently involves the parotid gland (extraoral), it can also arise from the minor salivary glands distributed throughout the oral cavity. 1. **Why Palate is Correct:** The **hard palate** is the most common site for minor salivary gland tumors, including pleomorphic adenoma. This is due to the high density of minor salivary glands located in the posterolateral aspect of the hard palate. Clinically, it presents as a slow-growing, painless, firm, and non-ulcerated swelling that does not move against the underlying bone (due to the tight mucoperiosteum). 2. **Why Other Options are Incorrect:** * **Upper Lip:** This is the second most common site for minor salivary gland pleomorphic adenomas. Interestingly, benign tumors are more common in the upper lip, whereas malignant minor salivary tumors are more common in the lower lip. * **Buccal Mucosa:** While minor salivary glands exist here, tumors in this location are significantly less frequent than those on the palate. * **Floor of the Mouth:** This is a rare site for pleomorphic adenoma. Swellings here are more likely to be ranulas, dermoid cysts, or tumors of the sublingual gland (which are frequently malignant). **High-Yield Clinical Pearls for NEET-PG:** * **Most common site (Overall):** Parotid gland (Superficial lobe). * **Most common site (Minor Salivary Glands):** Palate. * **Clinical Feature:** It is called "mixed tumor" because it contains both epithelial and mesenchymal (mucoid, chondroid) elements. * **Treatment:** Wide local excision with a cuff of normal tissue. Simple enucleation is avoided due to the presence of **pseudopods** (microscopic projections), which lead to high recurrence rates.

Q: What is the most common tumor of minor salivary glands?

Mucoepidermoid carcinoma. **Explanation:** The distribution and frequency of salivary gland tumors follow specific patterns based on the site of origin. While the Parotid gland is the most common site for salivary tumors overall, the **minor salivary glands** (found throughout the oral cavity, palate, and lips) have a higher propensity for malignancy. **1. Why Mucoepidermoid Carcinoma is correct:** **Mucoepidermoid carcinoma (MEC)** is the most common malignant tumor of the salivary glands overall and specifically the **most common tumor (and most common malignancy) of the minor salivary glands.** It typically presents as a painless, firm swelling, most frequently located on the hard palate. **2. Why the other options are incorrect:** * **Mixed Tumor (Pleomorphic Adenoma):** This is the most common tumor of the **major** salivary glands (especially the Parotid). While it can occur in minor glands, MEC surpasses it in frequency in these locations. * **Squamous Cell Carcinoma:** While this is the most common cancer of the oral cavity lining (mucosa), it does not arise from the glandular tissue itself. * **Epithelioma:** This is a non-specific term for epithelial tumors and is not a recognized primary classification for salivary gland neoplasms in this context. **High-Yield Clinical Pearls for NEET-PG:** * **The Rule of 80s (Parotid):** 80% of tumors are in the Parotid; 80% of Parotid tumors are Pleomorphic Adenomas; 80% are benign. * **Minor Salivary Glands:** Unlike the Parotid, nearly **50-60%** of minor salivary gland tumors are **malignant**. * **Adenoid Cystic Carcinoma:** This is the second most common malignancy of minor salivary glands and is notorious for **perineural invasion** and "skip lesions." * **Most common site for Minor Salivary Gland tumors:** The Palate.

Q: Bilateral parotid gland enlargement is seen in all of the following conditions except?

Systemic lupus erythematosus (SLE). ### Explanation The correct answer is **Systemic Lupus Erythematosus (SLE)**. While SLE is a multisystem autoimmune disease that can affect various organs, it is **not** typically associated with parotid gland enlargement. Instead, it primarily manifests with malar rashes, joint pain, and renal involvement. **Why the other options are incorrect:** * **Sarcoidosis:** This granulomatous disease frequently involves the parotid glands. The combination of parotid enlargement, uveitis, and facial nerve palsy is known as **Heerfordt’s syndrome** (Uveoparotid fever), a high-yield association for NEET-PG. * **Sjogren’s Syndrome:** This is a chronic autoimmune triad of keratoconjunctivitis sicca, xerostomia, and connective tissue disease. Bilateral, painless parotid swelling occurs in approximately 50% of patients due to lymphocytic infiltration. * **Viral Infection:** **Mumps** (Paramyxovirus) is the most common cause of acute bilateral parotid swelling. Other viruses like HIV, EBV, and Cytomegalovirus can also cause chronic bilateral enlargement. **High-Yield Clinical Pearls for NEET-PG:** * **Miculicz Disease:** Historical term for benign bilateral swelling of the lacrimal and salivary glands (now often linked to IgG4-related disease). * **Sialosis:** Non-inflammatory, non-neoplastic bilateral parotid enlargement often seen in **Alcoholism**, **Diabetes Mellitus**, and **Bulimia**. * **Warthin’s Tumor:** The only salivary gland tumor that can occasionally present bilaterally (though usually metachronous). * **Stensen’s Duct:** Opens opposite the crown of the upper second molar; its blockage leads to painful swelling.

Question 1

Which of the following develops from an unerupted tooth?

Accepted Answer

Dentigerous cyst

Answer

Dental cyst

Answer

Both of the above

Answer

None of the above

Question 2

A 16-year-old female patient presents with a one-week history of small ulcers on her cheeks and tongue. On general examination, a mild rise in temperature is noted. Oral examination reveals multiple ulcers on the buccal and labial mucosa. She also reports that she has her board exams in one week. What is the likely diagnosis?

Accepted Answer

Minor aphthous ulcers

Answer

Bullous pemphigoid

Answer

Traumatic ulcer

Answer

Tuberculoid ulcer

Question 3

Which stain is used to identify premalignant lesions of the oral cavity?

Accepted Answer

Toluidine blue

Answer

Malachite green

Answer

Potassium iodide

Answer

Iodine

Question 4

Which odontogenic tumor, when treated with simple curettage, is most likely to recur?

Accepted Answer

Odontogenic myxoma

Answer

Complex odontoma

Answer

Compound odontoma

Answer

Ameloblastic fibroma

Question 5

All of the following are true about mucoepidermoid carcinoma except?

Accepted Answer

Usually causes facial paralysis.

Answer

Most common radiation-induced neoplasm of the parotid gland.

Answer

Most common malignant salivary gland tumor in children.

Answer

Poorly differentiated in adults.

Question 6

Perforation of the palate is seen with which of the following conditions?

Accepted Answer

Tertiary syphilis

Answer

Minor aphthous ulcers

Answer

Major aphthous ulcers

Answer

All of the above

Question 7

Intraoral pleomorphic adenoma most commonly occurs in which location?

Accepted Answer

Palate

Answer

Buccal mucosa

Answer

Upper lip

Answer

Floor of the mouth

Question 8

What is the most common tumor of minor salivary glands?

Accepted Answer

Mucoepidermoid carcinoma

Answer

Mixed tumor

Answer

Squamous cell carcinoma

Answer

Epithelioma

Question 9

Which of the following statements is NOT true regarding the hard palate?

Accepted Answer

It is typically painful.

Answer

Maxillectomy may be required for treatment.

Answer

Lymphatic spread is a possible complication.

Answer

Histologically, it can present as squamous cell carcinoma or adenocarcinoma.

Question 10

Bilateral parotid gland enlargement is seen in all of the following conditions except?

Accepted Answer

Systemic lupus erythematosus (SLE)

Answer

Sarcoidosis

Answer

Sjogren's syndrome

Answer

Viral infection

Diseases of the Oral Cavity and Salivary Glands — MCQs

Diseases of the Oral Cavity and Salivary Glands — MCQs

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