Mole Inside the Mouth: When Pigmentation Is Concerning

Physiological pigmentation: brown patches on the gums (gingiva) common in people of African, South Asian, East Asian, and Middle Eastern ancestry. Bilateral, symmetric, present from childhood, stable. Completely normal and not a disease.

Melanotic macule: a single flat brown or tan spot, usually 2-10mm, on the lip mucosa, gum, or palate. Benign, stable for years.

Amalgam tattoo: a grey-blue spot in the mouth from silver fillings particles deposited in the mucosa during dental procedures. Stable, benign, often visible on dental X-rays.

Post-inflammatory pigmentation: brown patches from previous trauma, biting, dental work, or healed sores. Fades over months.

Black hairy tongue: dark coating on the tongue from elongated papillae, often related to smoking, certain medications, or poor oral hygiene. Reversible.

Nicotine staining: yellow-brown discolouration on teeth and gums from smoking or chewing tobacco.

Oral mucosal melanoma (OMM) is rare — less than 1% of all melanomas — but disproportionately deadly. Five-year survival is 15-30% even for early-stage cases, much worse than cutaneous melanoma at matched stages.

Reasons for poor outcomes:

Late diagnosis. People notice pigmentation but don't think 'cancer' until it's grown.

The mouth is rich in blood and lymphatic supply, allowing earlier spread.

Different molecular profile from skin melanoma; less responsive to some therapies.

Surgery in the oral cavity is more constrained than skin surgery.

The practical implication: any new, growing, asymmetric, or multi-coloured oral pigmented lesion deserves prompt evaluation. Threshold for biopsy is appropriately low. This is one of the cancers where 'wait and see' carries real cost.

New pigmented lesion in adulthood without obvious dental cause (filling, recent procedure).

Growing lesion over weeks to months.

Asymmetric or irregular borders.

Multiple colours within a single lesion (brown, black, blue, red, white).

Ulceration or non-healing surface.

Bleeding without trauma.

Lesion larger than 6-7mm.

Lesion in a high-risk site: hard palate, upper gum, or floor of mouth (these locations have higher OMM rates than buccal mucosa or tongue).

Any of these warrants oral medicine, dermatology, or oral surgery evaluation within 2-4 weeks.

OMM has different risk factors from cutaneous melanoma:

UV exposure is not the primary driver (the mouth is not directly UV-exposed).

Higher rates in people of Japanese, Chinese, and African ancestry (still rare in absolute terms).

Smoking and tobacco use may contribute (data mixed but plausible).

Formaldehyde exposure (rare, occupational).

Chronic irritation from poorly fitting dentures or sharp tooth edges may be a small risk.

Most OMM occurs in adults aged 50-80, with some preference for males.

If you have any of these risk factors and notice a new pigmented oral lesion, the threshold for evaluation is even lower.

Most oral pigmented lesions are first noticed during dental checks. Dentists are trained to identify obvious benign pigmentation (physiological, amalgam tattoo) but typically refer suspicious lesions to oral medicine, oral surgery, or dermatology.

If your dentist flags a lesion: follow the referral promptly.

If your dentist says 'it's probably nothing' but you are worried: ask for a referral anyway, especially if the lesion is new, growing, or has multiple colours.

If you have no dentist or it's been years since a check: book a dental appointment specifically for oral examination. Mention the lesion you noticed.

For known suspicious lesions, oral medicine specialists or oral and maxillofacial surgeons are usually the right specialists. Dermatologists also handle some oral cases. The biopsy is straightforward — small punch or excisional biopsy under local anaesthetic — and pathology distinguishes benign from melanoma reliably.

Within 1-2 weeks if any:

New oral pigmented lesion that has appeared in the past 6 months.

Growing oral pigmented lesion.

Lesion with irregular borders or multiple colours.

Non-healing oral ulcer or sore (over 4 weeks) regardless of pigmentation.

Bleeding from an oral lesion.

Lesion on hard palate, upper gum, or floor of mouth.

Within 4-8 weeks if any:

Longstanding lesion that has changed.

Multiple new lesions across the mouth.

Any pigmentation in someone with prior melanoma history (cutaneous or otherwise).

For any pigmented oral lesion that prompts the question 'should I get this checked?' — the answer is yes. Oral pigmentation is one of the higher-yield clinical signs in this region; biopsy threshold is low for good reason.