NDHCE General and Oral Pathology — Questions and Answers
Question 1: Which oral lesion is characterized by a white, non-wipeable plaque that cannot be attributed to any other condition and carries a risk of malignant transformation?
- Candidiasis
- Leukoplakia (Correct answer)
- Leukoedema
- White sponge nevus
Correct answer: Leukoplakia
Leukoplakia is defined as a white patch that cannot be rubbed off and cannot be classified as any other diagnosable disease, and it carries a risk of malignant transformation.
Question 2: A patient presents with a painless, slow-growing swelling on the palate that is firm on palpation and has been present for years. This description is most consistent with which salivary gland tumor?
- Mucocele
- Pleomorphic adenoma (Correct answer)
- Necrotizing sialometaplasia
- Mucoepidermoid carcinoma
Correct answer: Pleomorphic adenoma
Pleomorphic adenoma (benign mixed tumor) is the most common salivary gland tumor and presents as a slow-growing, painless, firm mass, most often on the palate among minor salivary gland sites.
Question 3: Which type of hypersensitivity reaction is responsible for anaphylaxis following administration of penicillin?
- Type II (cytotoxic)
- Type III (immune complex)
- Type I (IgE-mediated) (Correct answer)
- Type IV (delayed/cell-mediated)
Correct answer: Type I (IgE-mediated)
Anaphylaxis is a Type I (immediate) hypersensitivity reaction mediated by IgE antibodies on mast cells and basophils, triggering rapid release of histamine and other mediators.
Question 4: Oral hairy leukoplakia is caused by which virus and is strongly associated with immunosuppression?
- Human papillomavirus (HPV)
- Herpes simplex virus (HSV)
- Epstein-Barr virus (EBV) (Correct answer)
- Cytomegalovirus (CMV)
Correct answer: Epstein-Barr virus (EBV)
Oral hairy leukoplakia is caused by Epstein-Barr virus (EBV) and is most commonly seen in HIV-positive individuals as a marker of immunosuppression.
Question 5: A bluish, dome-shaped fluctuant nodule located on the lower lip mucosa is most likely which pathological entity?
- Fibroma
- Mucocele (Correct answer)
- Lipoma
- Ranula
Correct answer: Mucocele
A mucocele is caused by rupture of a minor salivary gland duct with mucous extravasation into surrounding tissue, appearing as a bluish, fluctuant swelling most often on the lower lip.
Question 6: Which systemic disease is most commonly associated with the oral manifestation of 'burning mouth syndrome' (BMS)?
- Hypothyroidism
- Type 2 diabetes mellitus (Correct answer)
- Rheumatoid arthritis
- Addison's disease
Correct answer: Type 2 diabetes mellitus
Type 2 diabetes mellitus is one of the systemic conditions most commonly associated with burning mouth syndrome, along with nutritional deficiencies and hormonal changes.
Question 7: The Wickham's striae pattern of fine white lace-like lines on the buccal mucosa is characteristic of which condition?
- Lichen planus (Correct answer)
- Erythema multiforme
- Pemphigus vulgaris
- Psoriasis
Correct answer: Lichen planus
Wickham's striae — interlacing white lines on the buccal mucosa — are pathognomonic of oral lichen planus, an immune-mediated mucocutaneous disease.
Question 8: Which pathological process describes irreversible pulpal necrosis resulting from ischemia after traumatic injury to the tooth?
- Internal resorption
- Hypercementosis
- Pulp calcification
- Pulp necrosis (Correct answer)
Correct answer: Pulp necrosis
Pulp necrosis is the death of pulpal tissue due to ischemia (loss of blood supply), often following trauma that severs the apical vessels, making it irreversible.
Question 9: A patient with Sjögren's syndrome is at highest risk for which oral complication?
- Gingival hyperplasia
- Rapid rampant dental caries (Correct answer)
- Oral candidiasis only
- Torus palatinus formation
Correct answer: Rapid rampant dental caries
Sjögren's syndrome causes severe xerostomia due to autoimmune destruction of salivary glands, dramatically increasing the risk of rapid rampant dental caries from loss of saliva's protective effects.
Question 10: Which type of cyst is derived from the reduced enamel epithelium and surrounds the crown of an unerupted tooth?
- Radicular cyst
- Dentigerous cyst (Correct answer)
- Lateral periodontal cyst
- Nasopalatine duct cyst
Correct answer: Dentigerous cyst
A dentigerous (follicular) cyst develops from the reduced enamel epithelium that surrounds the crown of an unerupted tooth, attaching at the cementoenamel junction.
Question 11: Erythroplakia is considered more clinically significant than leukoplakia because it has a higher rate of:
- Recurrence after treatment
- Spontaneous resolution
- Malignant transformation (Correct answer)
- Viral etiology
Correct answer: Malignant transformation
Erythroplakia (red velvety patches) has a significantly higher rate of malignant transformation than leukoplakia, with the majority of lesions showing dysplasia or carcinoma on biopsy.
Question 12: Which condition is characterized by bilateral, painful oral ulcers affecting the non-keratinized mucosa, often recurring monthly, and is NOT associated with trauma?
- Primary herpetic gingivostomatitis
- Recurrent aphthous stomatitis (RAS) (Correct answer)
- Recurrent herpes labialis
- Behçet's disease
Correct answer: Recurrent aphthous stomatitis (RAS)
Recurrent aphthous stomatitis presents as recurrent, painful ulcers on non-keratinized mucosa (e.g., buccal and labial mucosa), cycling approximately monthly, without a confirmed infectious etiology.
Question 13: An exophytic nodule of fibrous connective tissue on the gingiva caused by chronic low-grade irritation is best termed:
- Pyogenic granuloma
- Peripheral ossifying fibroma
- Peripheral giant cell granuloma
- Irritation fibroma (Correct answer)
Correct answer: Irritation fibroma
An irritation fibroma (traumatic fibroma) is a reactive hyperplasia of fibrous connective tissue in response to chronic irritation, appearing as a smooth, sessile or pedunculated nodule.
Question 14: Which radiographic appearance is most consistent with a periapical abscess?
- Well-defined radiolucency with a sclerotic border
- Diffuse radiolucency at the root apex (Correct answer)
- Generalized alveolar bone loss
- Widening of the periodontal ligament space only
Correct answer: Diffuse radiolucency at the root apex
A periapical abscess typically appears as an ill-defined, diffuse radiolucency at the root apex due to acute bone destruction without time for reactive bone formation.
Question 15: Which autoimmune blistering disease is characterized by suprabasilar acantholysis and positive Nikolsky's sign in the oral cavity?
- Mucous membrane pemphigoid
- Bullous pemphigoid
- Pemphigus vulgaris (Correct answer)
- Erythema multiforme
Correct answer: Pemphigus vulgaris
Pemphigus vulgaris involves autoantibodies against desmoglein proteins causing suprabasilar acantholysis, and the Nikolsky's sign (separation of epithelium with lateral pressure) is positive.
Question 16: Paget's disease of bone affecting the jaw would most likely produce which radiographic finding?
- Ground-glass opacity with loss of lamina dura
- 'Cotton wool' appearance (Correct answer)
- Floating teeth pattern
- Sun-ray pattern
Correct answer: 'Cotton wool' appearance
Paget's disease causes disorganized bone remodeling that radiographically produces a characteristic 'cotton wool' or 'cotton ball' pattern of mixed radiopaque and radiolucent areas.
Question 17: A patient with Addison's disease (primary adrenal insufficiency) may exhibit which distinctive oral finding?
- Geographic tongue
- Multifocal melanin pigmentation (Correct answer)
- Hairy tongue
- Torus mandibularis
Correct answer: Multifocal melanin pigmentation
Addison's disease causes elevated ACTH, which stimulates melanocytes, resulting in diffuse or focal melanin hyperpigmentation of the oral mucosa, particularly the buccal mucosa and gingiva.
Question 18: Which feature differentiates a pyogenic granuloma from an irritation fibroma clinically and histologically?
- Presence of bone formation
- High vascularity and tendency to bleed (Correct answer)
- Location on keratinized gingiva
- Association with systemic disease
Correct answer: High vascularity and tendency to bleed
Pyogenic granuloma is highly vascular with numerous blood vessels and bleeds easily upon probing or pressure, distinguishing it from the relatively avascular irritation fibroma.
Question 19: Fordyce spots in the oral cavity represent which anatomical variant?
- Ectopic minor salivary glands
- Sebaceous glands without associated hair follicles (Correct answer)
- Lymphoid aggregates
- Melanocyte clusters
Correct answer: Sebaceous glands without associated hair follicles
Fordyce spots are ectopic sebaceous glands (without hair follicles) found in the oral mucosa, appearing as yellowish, asymptomatic spots on the buccal mucosa and lips — a normal anatomical variant.
Question 20: Which condition involves replacement of normal stratified squamous epithelium by columnar-type epithelium in response to chronic irritation, representing a form of metaplasia?
- Dyskeratosis
- Acanthosis
- Epidermoid metaplasia
- Squamous metaplasia (Correct answer)
Correct answer: Squamous metaplasia
Squamous metaplasia is the replacement of one mature cell type by another (often columnar to squamous) in response to chronic irritation or environmental stress, representing an adaptive but reversible cellular change.
Question 21: Oral submucous fibrosis (OSMF), a premalignant condition, is most strongly associated with habitual use of which substance?
- Tobacco smokeless chew
- Areca nut (betel quid) (Correct answer)
- Alcohol
- Khat (Catha edulis)
Correct answer: Areca nut (betel quid)
Oral submucous fibrosis is caused primarily by the arecoline alkaloid in areca nut (betel quid), which stimulates fibroblast proliferation and collagen deposition leading to progressive fibrosis and trismus.
