Pigmented Lesions of Oral Mucosa Notes

Pigmented Lesions of Oral Mucosa

Healthy oral soft tissues typically exhibit a pink to red hue with slight color variations.
This coloration is influenced by:
- Presence or absence of keratin on the surface epithelium.
- Quantity and location (superficial or deep) of blood vessels in the stroma.
- Presence of adipocytes.
- Absence of melanin pigmentation in the basal cell layer.

Melanin:
- Synthesized by melanocytes and nevus cells.
- Appears brown, blue, or black based on the amount and location within the tissue.
Exogenous Pigmentation:
- Associated with trauma or iatrogenic events depositing foreign material into mucosal tissues.
- Substances may be ingested, absorbed, and distributed via blood, especially in areas of chronic inflammation (e.g., gingiva).
- Ingested substances may stimulate melanin production.
Chromogenic Bacteria:
- Can cause oral pigmentation, typically discoloring the dorsal tongue.
Foods and Drinks:
- Certain foods, drinks, and confectionaries can result in exogenous pigmentation, which is usually reversible.

Melanin is derived from tyrosine and synthesized by melanocytes in the basal cell layer.
In the skin, melanin protects against actinic irradiation and acts as a scavenger against cytotoxic intermediates.
Melanosis: Term used to describe diffuse hyperpigmentation.

Commonly caused by increased sun exposure.
Intraorally, it's often due to:
- Physiologic or idiopathic sources
- Neoplasia
- Medication or oral contraceptive use
- High serum ACTH (pituitary adrenocorticotropic hormone)
- Post-inflammatory changes
- Genetic or autoimmune disease
Biopsy: Required if the etiology is uncertain due to the potential for malignant melanoma, which may have a benign appearance.

Common, asymptomatic, small (1-3 mm), well-circumscribed, tan or brown macule.
Found on sun-exposed areas, especially in light-skinned individuals or those with red/blond hair.
Developmental in origin, more abundant and darker in childhood/adolescence.
Darkens with sun exposure (spring/summer) due to increased melanin production, not melanocyte number.
Number and color intensity diminish with age.
No treatment is generally required.

Benign, pigmented lesion.
Trauma may play a role, but sun exposure is not a precipitating factor.
More frequent in females, usually on the lower lip (labial melanotic macule) and gingiva.
Develops at any age, but generally presents in adulthood.
Congenital melanotic macules have been described, primarily on the tongue.
Small (<1 cm), well-circumscribed, oval or irregular, and uniformly pigmented.
Unlike an ephelis, it does not darken with sun exposure.

Benign, reactive melanocytic lesion unique to mucosal tissues.
Acute trauma or chronic irritation usually precedes development.
May resolve spontaneously.
More common in females in their 3rd to 4th decade, with 50% occurring on the buccal mucosa.