Diseases of the Oral Cavity and Salivary Glands Practice Questions

Q: Adenoid cystic carcinoma can cause lesion of which of the following nerves?

All of the above. **Explanation:** The correct answer is **D. All of the above**. The hallmark pathological feature of **Adenoid Cystic Carcinoma (ACC)** is its high propensity for **perineural invasion (PNI)**. Unlike many other tumors that spread primarily via lymphatics, ACC characteristically tracks along nerve sheaths, often extending far beyond the visible margins of the tumor. **Why "All of the above" is correct:** Adenoid cystic carcinoma most commonly involves the **parotid gland** and the **minor salivary glands** (frequently in the palate and tongue). * **Facial Nerve (CN VII):** When ACC occurs in the parotid gland, it frequently infiltrates the facial nerve, leading to facial palsy. * **Lingual and Hypoglossal Nerves:** When ACC involves the submandibular gland or the minor salivary glands of the floor of the mouth and tongue, it can track along the lingual nerve (causing sensory loss) and the hypoglossal nerve (causing tongue deviation/atrophy). **Clinical Pearls for NEET-PG:** * **Most Common Site:** The **Palate** (minor salivary glands) is the most common site overall, but it is also the most common malignant tumor of the **Submandibular** and **Sublingual** glands. * **Histology:** Look for the classic **"Swiss Cheese" appearance** (Cribriform pattern), which is the most common histological subtype. * **Spread:** It is notorious for **distant metastasis** (most commonly to the **Lungs**) via the bloodstream, often occurring years after initial treatment. * **Prognosis:** It is characterized by a slow, indolent growth but a relentless clinical course with a high rate of local recurrence due to its "skip lesions" along nerves.

Q: What is the investigation of choice for parotid fistula?

Sialogram. ### Explanation **Correct Answer: D. Sialogram** **Why it is the Investigation of Choice:** A **sialogram** (sialography) is the gold standard for investigating a parotid fistula. It involves the injection of a radio-opaque contrast medium into the Stensen’s duct followed by imaging. In the case of a fistula, the contrast will be seen leaking from the ductal system or gland parenchyma into the fistulous tract, effectively demonstrating the **site, size, and origin** of the leak. It also helps differentiate between a ductal fistula (injury to the main duct) and a glandular fistula (injury to the parenchyma), which is crucial for surgical planning. **Analysis of Incorrect Options:** * **A. CT Scan:** While useful for identifying tumors or abscesses, a routine CT lacks the dynamic contrast flow needed to pinpoint a fine fistulous communication. * **B. X-ray:** Plain radiographs are primarily used to detect radiopaque sialoliths (stones) but cannot visualize soft tissue tracts or fluid leaks. * **C. Starch Iodine Test (Minor’s Test):** This is the investigation of choice for **Frey’s Syndrome** (gustatory sweating), not a parotid fistula. It identifies sweat production on the skin, whereas a fistula involves the leakage of saliva. **High-Yield Clinical Pearls for NEET-PG:** * **Frey’s Syndrome:** Occurs due to aberrant regeneration of auriculotemporal nerve fibers. * **Management of Parotid Fistula:** Initial management is conservative (anti-sialagogues like Glycopyrrolate, pressure dressings). If it fails, surgical options include tympanic neurectomy (to cut parasympathetic supply) or parotidectomy. * **Sialography Contraindication:** It should never be performed during **acute infection** (sialadenitis) as it can retrograde spread the infection.

Q: Which of the following is the most common tumor of the salivary gland?

Pleomorphic adenoma. **Explanation:** **Pleomorphic Adenoma** (Option D) is the most common tumor of the salivary glands, accounting for approximately 60–70% of all salivary gland neoplasms. It is a benign mixed tumor containing both epithelial and mesenchymal elements. It most frequently involves the **parotid gland** (80% of cases), where it typically presents as a slow-growing, painless, firm swelling in the superficial lobe. **Analysis of Incorrect Options:** * **Mucoepidermoid Carcinoma (Option A):** This is the most common **malignant** salivary gland tumor in both adults and children. While common, its overall incidence is lower than that of the benign Pleomorphic Adenoma. * **Warthin’s Tumor (Option B):** Also known as Papillary Cystadenoma Lymphomatosum, it is the second most common benign tumor of the parotid. It is strongly associated with smoking and is the most common salivary tumor to present bilaterally or multicentrically. * **Acinic Cell Tumor (Option C):** This is a low-grade malignant tumor. It is unique because it is often bilateral (second only to Warthin’s) but is significantly rarer than Pleomorphic Adenoma. **High-Yield NEET-PG Pearls:** * **Rule of 80s for Parotid Tumors:** 80% are parotid, 80% are benign, 80% are Pleomorphic Adenoma, and 80% occur in the superficial lobe. * **Most common site for minor salivary gland tumors:** The Palate. * **Malignancy Risk:** The smaller the gland, the higher the risk of malignancy (e.g., Sublingual gland tumors are rare but ~80% are malignant). * **Carcinoma ex pleomorphic adenoma:** Refers to the malignant transformation of a long-standing Pleomorphic Adenoma.

Q: In Frey's syndrome, what is the neurotransmitter involved?

Acetylcholine. **Explanation:** **Frey’s Syndrome (Auriculotemporal Syndrome)** occurs due to the aberrant regeneration of nerve fibers following parotid surgery (parotidectomy) or trauma. 1. **Why Acetylcholine is correct:** The physiological basis of this syndrome lies in the **parasympathetic** nervous system. Normally, the **auriculotemporal nerve** carries postganglionic parasympathetic fibers that use **acetylcholine** to stimulate salivary secretion from the parotid gland. After injury, these regenerating parasympathetic fibers mistakenly grow into the overlying skin to innervate sweat glands and small blood vessels. Since sweat glands are also stimulated by cholinergic (acetylcholine) fibers, the stimulus intended for salivation (like seeing or smelling food) results in localized sweating and flushing of the temple area instead. 2. **Why the other options are incorrect:** * **Epinephrine & Norepinephrine:** These are the primary neurotransmitters of the sympathetic nervous system. While sweat glands are anatomically part of the sympathetic system, they are a unique exception as they are **cholinergic** (stimulated by acetylcholine). * **Serotonin:** This is a monoamine neurotransmitter primarily involved in mood regulation and GI motility; it has no role in the secretomotor pathway of the parotid or sweat glands. **High-Yield 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 **Sternocleidomastoid (SCM) flap** during surgery. * **Treatment:** Topical **Glycopyrrolate** or **Botulinum toxin (Botox)** injections (which block acetylcholine release).

Q: A 50-year-old smoker presents to the hospital with a painless oral lesion and white patch that develops in the oral cavity, as shown in the image. What is the diagnosis?

Leukoplakia. ***Leukoplakia*** - Leukoplakia is a clinical diagnosis for a white patch or plaque on the oral mucosa that **cannot be scraped off**, distinguishing it from other lesions like candidiasis. - It is strongly associated with chronic irritation, particularly **tobacco use** (as in this smoker), and is considered a **premalignant condition** with a risk of transforming into squamous cell carcinoma. *Candidiasis* - Oral candidiasis (thrush) presents as creamy white, curd-like plaques that **can typically be scraped off**, revealing an underlying erythematous and sometimes bleeding base. - It is an opportunistic fungal infection more common in **immunocompromised** patients, infants, or those using steroids or broad-spectrum antibiotics. *Lichen planus* - Oral lichen planus is a chronic inflammatory autoimmune disease that classically appears as a fine, lace-like network of white lines known as **Wickham's striae**. - While it can present as plaques, the typical reticular pattern is a key differentiating feature, and it is not primarily caused by smoking. *Oral cancer* - While this lesion could be oral cancer (squamous cell carcinoma), **leukoplakia** is the correct clinical descriptive term for the white patch itself. A definitive diagnosis of cancer requires a **biopsy**. - Oral cancers often present as **indurated ulcers**, red patches (erythroplakia), or fungating masses, which may or may not be painful, in addition to white patches.

Q: A patient with dental caries has developed a swelling in the area shown in the image. Diagnosis is:

Ludwig's angina. ***Ludwig's angina*** - The image shows a dental infection (caries) spreading from the tooth root into the **submandibular and sublingual spaces**, which is characteristic of Ludwig's angina. - This rapidly spreading cellulitis of the floor of the mouth is often odontogenic in origin and can cause significant **airway compromise**. *Vincent angina* - Vincent angina, also known as **necrotizing ulcerative gingivitis**, is an infection of the gums characterized by pain, bleeding, and ulceration. - It does not involve a deep space infection originating from dental caries with swelling in the submandibular region as depicted. *Collar stud abscess* - A collar stud abscess is a type of abscess that has two parts, superficial and deep, connected by a narrow tract, commonly seen in the **neck or parotid region** from tuberculous lymphadenitis. - It does not represent a dental infection spreading into the deep fascial spaces of the neck as shown in the image. *Pharyngo maxillary abscess* - A pharyngomaxillary (or parapharyngeal) abscess is a deep neck space infection often arising from tonsillar, dental, or parotid gland infections. - While it can be serious, the image specifically illustrates infection tracking from a carious tooth into the submandibular and sublingual spaces, pinpointing Ludwig's angina.

Question 1

Adenoid cystic carcinoma can cause lesion of which of the following nerves?

Accepted Answer

All of the above

Answer

Facial nerve

Answer

Lingual nerve

Answer

Hypoglossal nerve

Question 2

What is the investigation of choice for parotid fistula?

Accepted Answer

Sialogram

Answer

CT Scan

Answer

X-ray

Answer

Starch iodine Test

Question 3

What is the treatment for leukoplakia?

Accepted Answer

Surgical excision and cryotherapy

Answer

Radiation therapy

Answer

Topical chemotherapy

Answer

Repositioning of ill-fitting dentures

Question 4

All of the following are true about dental abnormalities EXCEPT:

Accepted Answer

Dentigerous cysts are most common in the upper third molars.

Answer

Dental cysts develop at the apices of carious teeth with necrotic pulp.

Answer

Dentigerous cysts contain unerupted teeth.

Answer

Ameloblastoma is the most common odontogenic tumor.

Question 5

All the following are true regarding a ranula EXCEPT?

Accepted Answer

A cyst with an epithelial lining, confined to the sublingual salivary gland

Answer

A pseudocyst with no connection to the salivary gland

Answer

Will change size following chewing and swallowing

Answer

Formed due to obstruction of the submandibular or minor salivary glands

Question 6

Which of the following is the most common tumor of the salivary gland?

Accepted Answer

Pleomorphic adenoma

Answer

Mucoepidermoid tumor

Answer

Warthin's tumor

Answer

Acinic cell tumor

Question 7

Which of the following is not an indication for radiotherapy in pleomorphic adenoma of the parotid gland?

Accepted Answer

Second histologically benign recurrence

Answer

Involvement of the deep lobe

Answer

Microscopically positive margins

Answer

Malignant transformation

Question 8

In Frey's syndrome, what is the neurotransmitter involved?

Accepted Answer

Acetylcholine

Answer

Epinephrine

Answer

Norepinephrine

Answer

Serotonin

Question 9

A 50-year-old smoker presents to the hospital with a painless oral lesion and white patch that develops in the oral cavity, as shown in the image. What is the diagnosis?

Accepted Answer

Leukoplakia

Answer

Candidiasis

Answer

Lichen planus

Answer

Oral cancer

Question 10

A patient with dental caries has developed a swelling in the area shown in the image. Diagnosis is:

Accepted Answer

Ludwig's angina

Answer

Vincent angina

Answer

Collar stud abscess

Answer

Pharyngo maxillary abscess

Diseases of the Oral Cavity and Salivary Glands — MCQs

Diseases of the Oral Cavity and Salivary Glands — MCQs

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