The etiology of this disorder remains unclear. Histopathological examinations of affected individuals suggest a functional alteration of melanocytes, which appear to be activated to continually synthesize higher amounts of melanin in a chronic fashion. However, the initial stimulus that induces this melanocyte activation is unknown.
Recognizing that this syndrome may mimic other pigmentary disorders, it is important to rule out those with potential for malignant transformation or other clinical implications. As a benign condition itself, the macular lesions of this syndrome do not require therapeutic intervention, although treatment may be pursued for cosmesis.
K13.70 – Unspecified lesions of oral mucosa
238706002 – Laugier-Hunziker syndrome
Differential Diagnosis & Pitfalls
- Physiologic pigmentation – Diffuse and bilateral, childhood onset (see multifocal or diffuse mucosal pigmentation).
- Peutz-Jeghers syndrome (periorificial lentiginosis) – Multiple diffuse and bilateral macules on the lips, oral / intranasal / conjunctival / rectal mucosa; childhood onset.
- Cronkhite-Canada syndrome – Nonfamilial gastrointestinal polyposis syndrome with associated cutaneous hyperpigmented macules, onychodystrophy, and alopecia.
- McCune-Albright syndrome – Polyostotic fibrous dysplasia, café-au-lait spots, and gonadotropin independent precocious puberty.
- Carney complex – Lentigines of the lips and intraoral pigmentation may be present.
- Primary hypoadrenalism (Addison disease) – Diffuse blue-black streaks or patches on oral mucosa and tongue in addition to hyperpigmentation, particularly in sun-exposed areas and flexural creases; also with fatigue, hypotension, electrolyte abnormalities. Palms and nails may also be affected.
- Other endocrine disorders: hyperthyroidism, Cushing disease
- Drug-induced oral pigmentation including from minocycline, antimalarials, clofazimine, and oral contraceptives
- Elevated heavy metal levels (lead, bismuth, silver, mercury, gold, arsenic) – Blue-black discoloration along the gingival margin.
- Postinflammatory pigmentation – Hyperpigmented lesions at sites of previous inflammatory or traumatic lesions or adjacent to active lesions (eg, lichen planus, pemphigus, pemphigoid).
- Smoker's melanosis – Brown-black lesions on the anterior labial and buccal mucosa in smokers.
- Scurvy – Ecchymosis, sometimes dusky purple discoloration of the gingiva with intraoral swelling and hemorrhage.
- Kaposi sarcoma – Bilateral brown to purple plaques / nodules in human immunodeficiency virus (HIV)-positive individuals; ulcerative and necrotic in advanced stages.
- Melanotic macule – Usually less than 1 cm, well demarcated, light or dark brown; more common in women and young adults. Though benign, should consider biopsy to rule out melanoma.
- Pigmented nevi – Brown or blue macule or papule commonly on the palate. Though benign, should consider biopsy to rule out melanoma.
- Melanoma – Brown or black patch with irregular borders, rapidly growing and more ulcerated as it advances; commonly on the palate, followed by the gingiva.
- Hemangioma – Red-bluish / purple lesion, flat or slightly raised, blanches with pressure, most commonly on tongue.
- Varix – Bluish / purple, irregular elevation, blanches with pressure, commonly on ventral tongue; if it does not blanch with pressure, it may contain a thrombus.
- Hemorrhage – Nonblanching macule, papule, or petechiae; may be ecchymotic.
- Inherited patterned lentiginosis