Diseases of the Oral Cavity and Salivary Glands Practice Questions

Q: A 40-year-old tobacco chewer presents for a routine oral examination. A non-scrapable white patch is noticed on the left buccal mucosa. What is the provisional diagnosis for this white lesion?

Leukoplakia. **Explanation:** The provisional diagnosis for a non-scrapable white patch in the oral cavity, especially in a patient with a history of tobacco use, is **Leukoplakia**. **1. Why Leukoplakia is correct:** By definition (WHO), Leukoplakia is a clinical term for a white patch or plaque that **cannot be rubbed off** and cannot be characterized clinically or pathologically as any other disease. It is a **premalignant condition** strongly associated with tobacco (smoking/chewing) and alcohol. The "non-scrapable" nature distinguishes it from Oral Candidiasis (which rubs off, leaving a raw base). **2. Why other options are incorrect:** * **Lichen Planus:** Typically presents as bilateral, symmetrical, lace-like white lines known as **Wickham’s striae**. It is an inflammatory condition, not primarily triggered by tobacco. * **Erythroplakia:** This refers to a **red** velvety patch. While it has a much higher malignant transformation rate than leukoplakia, it does not present as a white lesion. * **Submucous Fibrosis (OSMF):** Characterized by mucosal rigidity, vertical fibrous bands, and **trismus** (restricted mouth opening). While the mucosa may appear pale/blanched, it is a generalized condition rather than a localized "patch." **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Buccal mucosa and commissures. * **Highest malignant potential:** Proliferative Verrucous Leukoplakia (PVL) and Speckled Leukoplakia (Erythroleukoplakia). * **Biopsy:** Mandatory to rule out dysplasia or invasive carcinoma. * **Management:** Cessation of habits is the first step; surgical excision or laser ablation is preferred for dysplastic lesions.

Q: A 45-year-old male patient complains of a non-healing oral ulcer present for one month on the lateral border of the tongue. Histologic examination reveals abnormal keratinization. What is the possible diagnosis?

Squamous cell carcinoma. **Explanation:** **1. Why Squamous Cell Carcinoma (SCC) is correct:** Squamous cell carcinoma is the most common malignancy of the oral cavity, accounting for over 90% of cases. The **lateral border of the tongue** is the most frequent site for oral SCC. The clinical presentation of a **non-healing ulcer** (persisting for more than 3 weeks) in an adult is a classic "red flag" for malignancy. Histologically, SCC is characterized by the invasion of malignant epithelial cells into the subepithelial tissue and **abnormal keratinization**, often manifesting as "keratin pearls" or "epithelial pearls" in well-differentiated tumors. **2. Why other options are incorrect:** * **Basal Cell Carcinoma (BCC):** BCC typically affects the skin of the face (above the line joining the tragus to the angle of the mouth). It almost **never** occurs primarily within the oral cavity or on the tongue. * **Keratoacanthoma:** This is a rapidly growing skin tumor that often regresses spontaneously. While it shows keratinization, it typically occurs on sun-exposed skin and is rare on the mucous membranes of the tongue. * **Erythroplakia:** This is a clinical term for a red, velvety patch. While it is a high-risk **premalignant condition** (more likely to harbor dysplasia than leukoplakia), it is a clinical description rather than a histological diagnosis of an invasive ulcer. **Clinical Pearls for NEET-PG:** * **Most common site of Oral SCC:** Lower lip (overall), but **Tongue** (specifically lateral border) is the most common intra-oral site. * **Premalignant conditions:** Erythroplakia has a much higher transformation rate to SCC than Leukoplakia. * **Lymphatic spread:** Tongue SCC often spreads to Level II (upper deep cervical) lymph nodes. * **Field Cancerization:** This concept explains why patients with one oral SCC are at high risk for developing a second primary tumor in the upper aerodigestive tract.

Q: A 19-year-old woman has swelling in the back of her mouth for 2 months. Examination reveals swelling in the area of the left third molar. Radiographs show a radiolucent unilocular, well-circumscribed cyst surrounding the crown of the unerupted third mandibular molar. Histopathology shows the cyst is lined by stratified squamous epithelium and surrounded by a chronic inflammatory infiltrate. What is the most likely diagnosis?

Dentigerous cyst. **Explanation:** The clinical and radiological presentation is classic for a **Dentigerous Cyst** (also known as a Follicular Cyst). **Why it is correct:** A dentigerous cyst is the most common developmental odontogenic cyst. It originates from the separation of the follicle from around the crown of an **unerupted tooth**. The pathognomonic radiological feature is a **well-circumscribed, unilocular radiolucency** attached to the **cemento-enamel junction (CEJ)**, typically involving the mandibular third molars or maxillary canines. Histologically, it is lined by thin, non-keratinized stratified squamous epithelium. **Why other options are incorrect:** * **Ameloblastoma:** While it commonly occurs in the molar-ramus area, it usually presents as a "soap-bubble" or "honeycomb" multilocular radiolucency and is an aggressive neoplasm rather than a simple cyst. * **Odontogenic Keratocyst (OKC):** These often show a characteristic "picket-fence" or "tombstone" appearance of the basal layer on histology and have a high recurrence rate. They typically grow along the length of the bone without causing significant expansion initially. * **Odontoma:** These are dental hamartomas rather than cysts. They appear as radiopaque masses (resembling small teeth in "compound" type or a calcified mass in "complex" type) rather than a clear radiolucency. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Mandibular 3rd molar > Maxillary canine. * **Radiological hallmark:** Radiolucency attached to the neck of an unerupted tooth. * **Potential complication:** If left untreated, it can transform into Ameloblastoma or Squamous Cell Carcinoma. * **Treatment:** Enucleation and extraction of the involved tooth.

Q: What is the treatment for submandibular salivary gland duct calculi?

Opening the duct and removal of the calculus. **Explanation:** The primary goal in managing submandibular sialolithiasis (calculi) is to preserve the gland's function while removing the obstruction. **1. Why Option C is Correct:** Most submandibular stones (80%) are located in the **Wharton’s duct**. If the stone is palpable intraorally, the treatment of choice is **Sialolithotomy**. This involves making a longitudinal incision over the duct directly above the stone, removing the calculus, and leaving the duct open (marsupialization) to allow for drainage and prevent stricture. This procedure is conservative and avoids the risks associated with major surgery. **2. Why Other Options are Incorrect:** * **Option A & D:** Excision of the submandibular gland (Sialadenectomy) is reserved for stones located within the **gland parenchyma** (hilar stones) or cases where the gland has become chronically infected and non-functional (atrophic) due to recurrent obstruction. It is not the first-line treatment for ductal stones. * **Option B:** Opening the duct specifically at the frenulum is incorrect because the incision must be made **directly over the stone** to ensure successful retrieval. Opening only at the distal end may fail to reach stones located in the middle or posterior segments of the duct. **Clinical Pearls for NEET-PG:** * **Wharton’s Duct:** The most common site for salivary stones because the duct is long, the flow is against gravity, and the saliva is more alkaline and rich in calcium/mucin. * **Diagnosis:** 80% of submandibular stones are **radiopaque** (visible on X-ray/Occlusal views), whereas 80% of parotid stones are radiolucent. * **Sialendoscopy:** This is the modern "Gold Standard" for managing small, non-palpable ductal stones. * **Bimanual Palpation:** Always perform this to locate the stone before surgery.

Q: Which of the following is a premalignant lesion of the oral cavity?

Erythroplakia. **Explanation:** **Erythroplakia** is the correct answer because it is defined as a fiery red patch of the oral mucosa that cannot be characterized clinically or pathologically as any other definable disease. Among all oral premalignant lesions, erythroplakia carries the **highest risk of malignant transformation** (approximately 50% or higher). Histologically, it often shows severe epithelial dysplasia, carcinoma in situ, or even invasive squamous cell carcinoma at the time of biopsy. **Analysis of Incorrect Options:** * **Lichen Planus (Option A):** While the World Health Organization (WHO) classifies Oral Lichen Planus as a *premalignant condition* (specifically the erosive type), it is not a primary premalignant *lesion* like erythroplakia. Its transformation rate is significantly lower (approx. 1%). * **Bowen Disease (Option B):** This is a form of intraepidermal squamous cell carcinoma (carcinoma in situ) typically involving the **skin**. While it represents a malignant process, it is not a standard clinical term used for oral cavity premalignant screening in the same context as erythroplakia or leukoplakia. * **Behçet Disease (Option D):** This is a multi-system inflammatory vascular disorder characterized by recurrent aphthous ulcers, genital ulcers, and uveitis. It is **not** a premalignant condition. **High-Yield Clinical Pearls for NEET-PG:** * **Most common premalignant lesion:** Leukoplakia. * **Most common site for Leukoplakia:** Buccal mucosa. * **Highest malignant potential:** Erythroplakia > Speckled Leukoplakia (Erythroleukoplakia) > Leukoplakia. * **Premalignant Conditions:** Oral Submucous Fibrosis (OSMF), Lichen Planus, and Xeroderma Pigmentosum. * **Key Histology:** Look for "Dysplasia" (hyperchromatic nuclei, increased mitotic figures, and loss of polarity).

Q: What is the most common complication following the removal of a mandibular third molar?

Dry socket. **Explanation:** The most common complication following the extraction of a mandibular third molar is **Dry Socket**, also known as **Alveolar Osteitis**. **1. Why Dry Socket is the Correct Answer:** Dry socket occurs when the blood clot at the extraction site either fails to form or undergoes premature lysis (fibrinolysis). This exposes the underlying alveolar bone, leading to intense, radiating pain typically starting 2–4 days post-extraction. It occurs in approximately 5–30% of mandibular third molar extractions, making it statistically the most frequent postoperative issue. **2. Analysis of Incorrect Options:** * **Lingual nerve damage:** While a significant concern due to the proximity of the nerve to the third molar, it is a relatively rare complication (occurring in ~1–2% of cases) compared to dry socket. * **Mandibular fracture:** This is a rare, severe complication usually resulting from excessive force during the use of elevators in a weakened or deeply impacted bone. * **Bleeding:** While primary hemorrhage is common immediately after surgery, persistent or secondary bleeding is less frequent than the incidence of alveolar osteitis. **3. NEET-PG High-Yield Pearls:** * **Risk Factors:** Smoking, oral contraceptives, poor oral hygiene, and excessive irrigation/trauma during surgery increase the risk of dry socket. * **Clinical Feature:** Characterized by "exquisite pain" and a foul odor (halitosis), but notably **lacks signs of infection** like fever or pus. * **Management:** Treatment is symptomatic. The socket is irrigated with saline and packed with a sedative dressing (e.g., **Zinc Oxide Eugenol** or Alvogyl). Antibiotics are generally not required unless systemic infection is present.

Question 1

Which of the following predisposes to oral cancer?

Accepted Answer

Lichen planus

Answer

Erythroplakia

Answer

Leukoplakia

Answer

Submucosal fibrosis

Question 2

Frey's syndrome is caused by?

Accepted Answer

Post-traumatic aberrant regeneration of facial nerve fibers with parasympathetic innervation from the auriculotemporal nerve.

Answer

Lesions involving the greater auricular nerve and the auriculotemporal nerve.

Answer

Damage to the facial nerve in conjunction with the greater auricular nerve.

Answer

None of the above.

Question 3

A 40-year-old tobacco chewer presents for a routine oral examination. A non-scrapable white patch is noticed on the left buccal mucosa. What is the provisional diagnosis for this white lesion?

Accepted Answer

Leukoplakia

Answer

Lichen planus

Answer

Erythroplakia

Answer

Submucous fibrosis

Question 4

A 45-year-old male patient complains of a non-healing oral ulcer present for one month on the lateral border of the tongue. Histologic examination reveals abnormal keratinization. What is the possible diagnosis?

Accepted Answer

Squamous cell carcinoma

Answer

Basal cell carcinoma

Answer

Keratoacanthoma

Answer

Erythroplakia

Question 5

A 19-year-old woman has swelling in the back of her mouth for 2 months. Examination reveals swelling in the area of the left third molar. Radiographs show a radiolucent unilocular, well-circumscribed cyst surrounding the crown of the unerupted third mandibular molar. Histopathology shows the cyst is lined by stratified squamous epithelium and surrounded by a chronic inflammatory infiltrate. What is the most likely diagnosis?

Accepted Answer

Dentigerous cyst

Answer

Ameloblastoma

Answer

Odontogenic keratocyst

Answer

Odontoma

Question 6

What is the treatment for submandibular salivary gland duct calculi?

Accepted Answer

Opening the duct and removal of the calculus

Answer

Excision of the submandibular gland

Answer

Opening the duct at the frenulum

Answer

Excision of the gland and duct

Question 7

Trismus following a lower molar extraction, presenting after 4 weeks, may be due to which of the following complications?

Accepted Answer

Breakage of needle in the pterygomandibular space

Answer

Hematoma of the temporomandibular joint (TMJ)

Answer

Abscess in the submasseteric space

Answer

Retained root stump in the extraction socket

Question 8

Which of the following is a premalignant lesion of the oral cavity?

Accepted Answer

Erythroplakia

Answer

Lichen planus

Answer

Bowen disease

Answer

Behçet disease

Question 9

What is the most common complication following the removal of a mandibular third molar?

Accepted Answer

Dry socket

Answer

Lingual nerve damage

Answer

Mandibular fracture

Answer

Bleeding

Question 10

Mikulicz's disease presents as:

Accepted Answer

Enlargement of parotid, submandibular salivary, and lacrimal glands

Answer

Enlargement of upper cervical lymph nodes

Answer

Systemic illness with dry mouth, joint pain, and fever

Answer

Fever, hepatosplenomegaly, and lymphadenopathy

Diseases of the Oral Cavity and Salivary Glands — MCQs

Diseases of the Oral Cavity and Salivary Glands — MCQs

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