Oral Melanocytic Nevi and Malignant Melanoma

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Questions and Answers

What is the preferred site for oral melanocytic nevi?

Tongue

Palate and gingiva (correct)

Floor of the mouth

Upper lip

What is necessary to confirm the diagnosis of oral melanocytic nevi?

Ultraviolet light exposure

Radiological examination

Biopsy (correct)

Clinical examination

At what age does the incidence of malignant melanoma peak?

90-94 years

70-74 years

60-64 years

80-84 years (correct)

What is a risk factor for cutaneous melanoma?

Fair complexion Signup and view all the answers

What is the typical appearance of early oral melanomas?

Dark brown or black flat patches Signup and view all the answers

What is the stage of melanoma where the malignant melanocytes grow only within the epithelium?

Radial growth phase Signup and view all the answers

What is the most common site for oral malignant melanoma?

Palate and upper alveolar ridge Signup and view all the answers

What is the stage of melanoma where the melanocytes extend out of the epithelium into the connective tissue?

Vertical growth phase Signup and view all the answers

What is the primary pathophysiological mechanism associated with oral melanoacanthoma?

Acute regional trauma or chronic irritation Signup and view all the answers

What is the typical size range of oral melanoacanthoma lesions?

A few millimeters to several centimeters Signup and view all the answers

What is the primary distinguishing feature of oral melanoacanthoma histologically?

Spongiotic epithelium containing dendritic pigmented melanocytes Signup and view all the answers

Why is an incisional biopsy necessary for oral melanoacanthoma diagnosis?

To rule out malignant melanoma Signup and view all the answers

What are melanocytic nevi commonly referred to as?

Moles Signup and view all the answers

What is the primary cause of focal oral pigmentation in melanocytic nevi?

Benign proliferation of melanocytes Signup and view all the answers

What is the characteristic appearance of intraoral melanocytic nevi?

Circumscribed brown to black patches, usually flat and approximately 5 or 6 mm across Signup and view all the answers

Which of the following factors contributes to the development of melanocytic nevi?

Environmental and genetic factors Signup and view all the answers

What is the estimated prevalence of oral/labial melanotic macules in the population?

3% of the population Signup and view all the answers

In which age group are oral/labial melanotic macules typically observed?

Fourth and fifth decades Signup and view all the answers

What is the primary cause of oral/labial melanotic macules?

Unknown etiology Signup and view all the answers

Where are oral melanotic macules most commonly observed?

Palate and gingiva Signup and view all the answers

What is the typical size of oral/labial melanotic macules?

Less than 1 cm in diameter Signup and view all the answers

What is the malignant potential of oral/labial melanotic macules?

No malignant potential Signup and view all the answers

What is the recommended management for suspected oral/labial melanotic macules?

Excisional biopsy Signup and view all the answers

What is the most common demographic characteristic of oral melanoacanthoma?

Dark-skin females Signup and view all the answers

Study Notes

Melanocytic Lesions

Palate and gingiva are favored sites for oral melanocytic lesions.
Histologically, a cluster of naevus cells is seen below the epithelium.

Malignant Melanoma

Malignant melanoma is a neoplasm of melanocytic origin, with most cases occurring on the skin.
Incidence of malignant melanoma increases with age, reaching a peak between 80 and 84 years.
Oral malignant melanoma occurs much less frequently than its cutaneous counterpart.
Ultraviolet light exposure, fair complexion, and sun sensitivity cause cutaneous melanoma, but no aetiological factors are known for mucosal melanoma.
Malignant melanomas may develop denovo or from a preexisting benign melanocytic lesion.

Clinical-Pathologic Features of Malignant Melanoma

The most frequent sites are the palate and upper alveolar ridge.
Early oral melanomas are asymptomatic dark brown or black flat patches.
Symptoms only develop in the late stages with nodular growth, pain, ulceration, bleeding, or loosening of teeth.
Melanomas grow in a predictable fashion, initially spreading laterally within the epithelium, and later extending into the connective tissue.

Oral Melanoacanthoma

Oral melanoacanthoma typically presents as a diffuse, rapidly enlarging area of macular pigmentation.
Histologically, it is characterized by spongiotic epithelium containing dendritic pigmented melanocytes throughout the lesional epithelium.
The pathophysiologic mechanism is most consistently associated with acute regional trauma or chronic irritation.

Patient Management

A biopsy is necessary to confirm the diagnosis of oral melanocytic nevi and to rule out malignant melanoma.
Treatment of oral melanoacanthoma is typically not indicated after diagnosis has been established.

Melanocytic Nevus

Melanocytic nevi, commonly referred to as “moles,” represent a group of benign tumors that develop due to melanocytic growth and proliferation.
In general, melanocytic nevi are acquired lesions with both environmental and genetic factors thought to play a role in their development.

Clinical-Pathologic Features of Melanocytic Nevus

Intraoral lesions are unusual and form circumscribed brown to black patches, usually flat, approximately 5 or 6 mm across.
Oral/labial melanotic macules are present in up to 3% of the population, are typically observed in patients in the fourth and fifth decades, and have a 2:1 female predilection.

Oral/Labial Melanotic Macules

Oral/labial melanotic macules are solitary, well-circumscribed lesions that are typically less than 1 cm in diameter.
They may appear on any surface but are most commonly observed on the buccal mucosa, gingiva, and palate.
Histopathological analysis reveals an increase in melanin in the basal and parabasal layers of normal stratified squamous epithelium without an increase in the number of melanocytes.

Patient Management of Oral/Labial Melanotic Macules

Oral/labial melanotic macules are considered benign lesions without malignant potential.
Since early malignant melanoma may have a similar clinical appearance, it is strongly advisable to perform an excisional biopsy for any suspected macules.

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Description

This quiz covers the characteristics and management of oral melanocytic nevi and malignant melanoma, including their histology and diagnosis.