Oral Mucosa Diseases Overview

Oral Mucosa Diseases (OMD)

• Aphthous stomatitis (ulcerative stomatitis): Small, painful sores (ulcers) commonly appearing in childhood, recurring frequently. Cause unknown; predisposing factors include stress, fever, and certain foods.

• Gross: Small (less than 1 cm), painful, shallow ulcers, located on the oral mucosa and tongue.

• Fate: Resolves within 7-14 days without scarring.

• Herpes infections: Caused by HSV-1, rarely HSV-2. Can cause acute herpetic gingivostomatitis in children.

• Gross: Vesicles containing clear fluid, typically found on lips and oral mucosa.

• Microscopic: Cellular edema, intranuclear inclusion bodies, and giant cells.

• Fate: Vesicles heal within 3-4 weeks.

• Oral candidiasis (moniliasis, thrush): Common fungal infection in infants and individuals with impaired immunity (e.g., diabetes, neutropenia).

• Caused by Candida Albicans; a normal inhabitant of the oral cavity (in 30-40% of the population).

• Gross: Whitish areas on an inflamed oral mucosa.

• Leukoplakia: White plaque on the oral mucosa or tongue due to epithelial thickening.

• Causes: Heavy smoking, chronic friction from a ragged tooth, and alcohol abuse.

• Malignant change occurs in 3-6% of cases.

• Microscopic: Acanthosis (increased thickness of prickle cells), hyperkeratosis (hypertrophy of the horny layer), and potentially dysplastic changes.

• Glossitis: Inflammation of the tongue, presenting as a painful tongue, changes in texture (atrophy of papillae), and/or changes in color (beefy-red).

• Causes include: Anemia (iron-deficiency or pernicious), vitamin B deficiencies, and infections, certain medications (e.g., sulphanilamide, sulphathiazole, ACE inhibitors and albuterol).

• Oral carcinoma (squamous cell carcinoma): Constitutes 95% of oral cancers; develops between ages 50-70.

• Causes: Tobacco smoking (most common), alcohol abuse, leukoplakia, human papilloma virus (HPV) infection, chronic irritation (e.g., from a ragged tooth).

• Gross appearance: Ulcerative or verrucous lesions (exophytic/raised growth), often found on the floor of the mouth, tongue, and soft palate.

• Microscopic: Typical squamous cell carcinoma with variable differentiation.

• Malignant cells, well-differentiated; formation of cell nests.

Salivary Gland Diseases (SGD)

• Oral mucoceles: Most common salivary gland lesions, caused by ductal blockage due to trauma or inflammation.

• Gross: Cyst filled with mucus, varying in size, typically affecting small glands on the lower lip.

• Acute sialadenitis: Inflammation of the major salivary glands, possibly due to viral, bacterial, or autoimmune factors. Mumps is the most common viral cause, leading to parotid gland enlargement and inflammation. Bacterial sialadenitis can be secondary to ductal obstructions (like stones) or bacterial invasion.

• Chronic sialadenitis: Occurs due to diminished saliva secretion and subsequent inflammation, often stemming from autoimmune disorders like Sjögren's syndrome. Symptoms include dry eyes (kerato-conjunctivitis sicca), and dry mouth (xerostomia)

• Presence of diffuse inflammation and focal lymphocytic aggregates.

• Salivary gland tumors: -Incidence: Substantially high incidence in parotid glands (65–80%) with (15–30% being malignant). -10% in submandibular glands (with 30–40% malignancy) and 10% in minor salivary glands.

• Classification: Exhibit both benign and malignant varieties.

• Pleomorphic adenoma (benign mixed salivary tumor): Benign, slow-growing, painless swelling typically in the parotid gland at the lower jaw angle.

• Gross: Well-demarcated, encapsulated mass, rarely exceeding 6 cm in greatest dimension.

• Microscopic: Epithelial and connective tissue components.

• Warthin tumor (papillary cystadenoma lymphomatosum): Less common than pleomorphic adenoma, usually found in the parotid gland, often in smokers.

• Gross: Typically small, well-circumscribed, and encapsulated. May be bilateral in 10% of cases.

• Microscopic: Cystic spaces lined by two layers of cells, with notable lymphoid tissue.

• Mucoepidermoid carcinoma: Common salivary gland carcinoma (15%), measuring up to 8 cm in diameter and lacking a well-defined capsule.

• Microscopic: Sheets of malignant squamous cells and mucous cells filled with mucin, pushing nuclei to the periphery.

• Prognosis: High grade tumors have a 25% recurrence rate; 50% 5-year survival rate.

• Adenoid cystic carcinoma: Relatively uncommon, characterized by small cells with scant cytoplasm, arranging in tubular or cribriform patterns.

• Prognosis: 5-year survival rate approximating 60%.

• Acinic cell tumor: Relatively uncommon, making up about 3% of salivary gland tumors, mainly affecting the parotid gland.

• Microscopic: Tumor cells resemble normal salivary serous acinar cells even though they are malignant.

• Prognosis: 5-year survival rate close to 90%.