Pigmented Lesions in the Orofacial Region

Flashcards covering classification, clinical features, histopathology, differential diagnosis, and management of endogenous and exogenous pigmented lesions of the orofacial region.

What main tissue interactions create the normal pink-to-red hue of healthy oral mucosa?

Surface keratinization, vascularity of the stroma, presence of submucosal fat, and absence of basal-layer melanin.

Which three endogenous pigments most commonly cause oral discoloration?

Hemoglobin, hemosiderin, and melanin.

What colors are typically produced by hemoglobin, hemosiderin, and melanin respectively in oral tissues?

Hemoglobin – red/blue; Hemosiderin – brown; Melanin – brown/black/blue (depending on depth).

Superficial melanin deposition appears in color, whereas deeper deposition appears .

Brown; black to blue.

Name the two broad categories of oral mucosal pigmentation.

Endogenous melanotic pigmentation and exogenous pigmentation.

List three examples of focal (solitary) endogenous melanotic lesions.

Oral/labial melanotic macule, melanocytic nevus, malignant melanoma.

Give three causes of multifocal or diffuse endogenous melanosis.

Physiologic (ethnic) pigmentation, drug-induced melanosis, smoker’s melanosis, post-inflammatory hyperpigmentation, melasma.

Which systemic diseases are classically associated with oral mucosal melanosis? Name two.

Addison’s disease (adrenal insufficiency) and Peutz–Jeghers syndrome.

What is the most common intraoral site of physiologic (ethnic) pigmentation?

Gingiva.

Physiologic pigmentation is caused by increased rather than increased .

Melanin production; melanocyte number.

Which habits and hormones enhance smoker’s melanosis prevalence?

Cigarette or pipe smoking and female sex hormones (e.g., oral contraceptives).

Where is smoker’s melanosis most frequently seen intraorally?

Anterior labial gingiva.

What happens to smoker’s melanosis after smoking cessation?

Pigmentation gradually diminishes over months to years.

Define an oral melanotic macule.

A focal, flat, pigmented lesion representing an oral freckle, post-inflammatory pigment, or a manifestation of systemic disease.

Which two syndromes should be considered when multiple oral melanotic macules are present?

Peutz–Jeghers syndrome and Addison’s disease.

Peutz-Jeghers syndrome inheritance pattern and key systemic manifestation?

Autosomal dominant; intestinal hamartomatous polyps.

Why does Addison’s disease cause diffuse mucocutaneous pigmentation?

Adrenal cortisol deficiency leads to excess ACTH and MSH, stimulating melanocytes.

What are café-au-lait macules and what condition is suspected when six or more >1.5 cm are present?

Brown cutaneous patches with irregular borders; neurofibromatosis type 1.

Pigmented neuroectodermal tumor of infancy usually affects infants under what age and in which bone?

Under 6 months old; maxilla.

Radiographically, how does a pigmented neuroectodermal tumor of infancy appear?

Ill-defined radiolucency that may contain developing teeth.

Name the four microscopic subtypes of nevomelanocytic nevus based on cell location.

Junctional, intradermal/intramucosal, compound, and blue nevus.

Which nevus subtype is most common in the oral cavity?

Intramucosal nevus.

What is the standard management for any undiagnosed pigmented oral lesion suspected to be a nevus?

Excisional biopsy.

State the two growth phases common to all melanomas.

Radial (horizontal) growth phase and vertical (invasive) growth phase.

Which two intraoral sites account for most oral melanomas?

Palate and maxillary gingiva.

List three clinical features that raise suspicion for oral melanoma.

Mixed colors (brown/black/blue/red), asymmetry, and irregular borders.

Five-year survival for oral melanoma is approximately _ compared to cutaneous melanoma’s 65 %.

20 %.

What is an amalgam tattoo and where is it most commonly found?

Iatrogenic implantation of amalgam particles; gingiva, buccal mucosa, palate, or tongue adjacent to amalgam-restored teeth.

Which imaging finding may help confirm an amalgam tattoo?

Radiopaque particles in soft-tissue radiograph.

Graphite tattoos typically result from what childhood injury?

Accidental pencil puncture implanting graphite into mucosa.

What laser modality can be used to remove ornamental mucosal tattoos?

Q-switched laser therapy.

Which tetracycline derivative is notorious for causing oral and skin pigmentation after prolonged high-dose therapy?

Minocycline.

Name three drugs besides tetracyclines that can induce oral mucosal pigmentation.

Chloroquine, amiodarone, zidovudine (AZT), cyclophosphamide.

Heavy metal exposure can produce a linear gray-black band along the gingiva called a _ line (give one example).

Lead line (or bismuth line, platinum line, etc.).

What oral side effect can chronic bismuth subsalicylate use cause?

Generalized black tongue from bismuth sulfide deposition.

Define argyria and chrysiasis.

Argyria – blue-gray discoloration from silver; Chrysiasis – blue-gray/purple discoloration from gold.

Which oral condition presents with elongated, hyperkeratotic filiform papillae colonized by chromogenic bacteria?

Black (or brown/green) hairy tongue.

List two behaviors or substances linked to black hairy tongue.

Tobacco smoking and broad-spectrum antibiotic therapy (also coffee, bismuth, psychotropics).

First-line management for hairy tongue involves what simple measure?

Mechanical debridement—brushing or scraping the tongue and limiting staining foods/drinks.

Which occupational hazard may lead to mercury intoxication in dental personnel?

Chronic inhalation of mercury vapor from improperly handled dental amalgam.

Give two workplace precautions to reduce mercury vapor exposure in dental offices.

Store mercury in sealed containers and use water spray plus suction when grinding amalgam (others: sulfur cover on spills, good ventilation, sealed capsules).

What histologic finding is common to amalgam, graphite, and medicinal metal tattoos?

Black or brown particulate material within collagen fibers, vessel walls, or macrophages.

Which pigmentation disorder shows increased melanin in basal keratinocytes but normal melanocyte numbers on histology?

Melanotic macule.

Post-inflammatory pigmentation is often seen surrounding lesions of what chronic mucocutaneous disease?

Lichen planus.

Which syndrome combines mucocutaneous macules with soft-tissue and cardiac myxomas?

Carney complex (myxoma–endocrine syndrome).

What rare acquired disorder shows oral, lip, and nail streak pigmentation without intestinal polyps?

Laugier–Hunziker syndrome.

Blue nevus cells are located in the connective tissue and are histologically shaped.

Deep; spindle.

Why is early biopsy critical for pigmented lesions of the palate and gingiva?

These sites are common for oral melanoma, and early lesions may mimic benign pigmentation.

Explain why melanomas of oral mucosa often have poorer prognosis than skin melanomas (give one reason).

They are detected later and often thicker at diagnosis; surgical margins are harder to achieve in oral cavity.

Which heavy metal–based chemotherapy drug can cause a platinum gingival line?

Cisplatin (cis-platinum).

What color change occurs in argyria affecting the oral cavity?

Diffuse blue-gray discoloration.

Describe the appearance of medicinal silver-associated oral pigmentation histologically.

Brown/black granular particles dispersed throughout connective tissue, similar to amalgam tattoo.

Which laser therapy is effective for removing carbon-based amateur oral tattoos?

Q-switched lasers (e.g., Q-switched Nd:YAG).

In smoker’s melanosis, pigmentation intensity correlates with what two factors?

Duration of smoking and number of cigarettes (dose).

What is the usual management for an amalgam tattoo if diagnosis is certain?

No treatment; biopsy only if diagnosis is uncertain.

Name two childhood malignancies considered in the differential diagnosis of pigmented neuroectodermal tumor of infancy.

Neuroblastoma and rhabdomyosarcoma.

What term is used for oral biopsies showing increased atypical junctional melanocytes insufficient for melanoma diagnosis?

Atypical melanocytic proliferation (high-risk lesion).

Which oral lesion is characterized clinically by an asymptomatic, persistent, symmetric pigmentation that spares gingival architecture?

Physiologic (ethnic) pigmentation.

What microscopic pattern is seen in pigmented neuroectodermal tumor of infancy?

Alveolar nests of small central neuroendocrine-like cells with peripheral larger melanin-containing cells.