Laugier Hunziker Syndrome

 

Laugier-Hunziker syndrome (LHS) was initially described in 1970 as acquired, benign hyperpigmentated macules of the lips and buccal mucosa frequently associated with longitudinal melanonychia. Extended mucocutaneous features have been observed since that original description, including macular pigmentation of the genitalia. No underlying systemic abnormalities are associated with LHS, and no malignant predisposition exists. This lack of somatic abnormalities has moved some authorities to propose a name change to Laugier and Hunziker pigmentation.¹ When associated with nonclassic body locations or atypical features, the name idiopathic lenticular mucocutaneous hyperpigmentation has been used.²

The etiology of melanosis in LHS is unknown. A lack of family members with LHS is characteristic in most cases. To date, only one case of familial LHS has been described, which involved a mother and 2 daughters.³ Environmental risk factors have not been identified.

The incidence is rare, but it is likely underreported. Three patients, including 1 white female and 2 Hispanic females, have been described in the United States.

The prevalence appears to be higher in France and Italy when compared with the United Kingdom and the United States. Worldwide, approximately 60 cases were reported from 1970-1991. Among the patients described prior to 1989, 27 (93%) of 29 patients were from continental Europe. To date, more than 100 cases have been described.⁴

Systemic illness and malignancy are not features of LHS. Such findings in association with mucocutaneous melanotic hyperpigmentation exclude the diagnosis of LHS.

• LHS mainly affects whites; however, persons of Hispanic, Arabic, or Asian⁵ descent have been described.
• Idiopathic buccal melanosis without longitudinal melanonychia is a normal finding in 38% of black patients and in 5% of white patients. Physiologic melanoplakia, a term also used to describe idiopathic racial or ethnic melanosis, is most commonly noted on the gingiva of individuals with darker skin types. The histopathologic features of LHS are indistinguishable from those of physiologic melanoplakia.
• Longitudinal melanonychia (also known as melanonychia striata) without associated mucosal melanotic macules is a normal finding in 77% of blacks by age 20 years, and it is seen in 90% of blacks by the fifth decade of life. It most commonly occurs on the thumbs, with onset often during infancy or puberty.

• LHS was initially predominantly thought to affect females, with an estimated female-to-male ratio of 2:1. However, the idea that LHS is equally distributed between the sexes is gaining popularity.⁴

• Essential melanotic pigmentation typically develops during early to middle adulthood, in persons aged 20-40 years, but it can occur as late as the sixth or seventh decade of life. A mean age of 52 years⁶ and a median age of 42 years⁷ have been reported.
• Physiologic (racial or ethnic) melanosis characteristically occurs during the first 3 decades of life.
• Peutz-Jeghers syndrome (PJS), a major differential diagnosis of LHS, usually has its onset at birth or during the first few years of life. However, sporadic cases of PJS have been reported in as many as 40% of cases, and it can have a late onset. See Peutz-Jeghers Syndrome for more information on this syndrome. Additionally, the Medscape CME course Hamartomatous Polyposis Syndromes may be of interest.

• Oral pigmentation is most commonly present on the buccal mucosa and the lips (usually the lower lip), but it can also occur on the gingiva, the tongue, the soft palate, and the hard palate. Macules are brown, black, or slate with a smooth surface. They may be solitary or confluent. Round, lenticular, and linear lesions have been described, and they may be well defined or indistinct. On average, the macules are 5 mm or smaller; however, buccal lesions as large as 1 cm have been described. Oral hyperpigmentation may exist alone or in combination with nail and/or skin pigmentation. Of the 5 cases originally described by Laugier and Hunziker, 40% had oral involvement only. Subsequent reports have also described the onset of oral pigmentation following melanonychia.
• Nail hyperpigmentation occurs in an estimated 60% of cases, and it is permanent. Typically, multiple nails from both the fingers and the toes are involved. The degree of pigmentation may vary between streaks on the same patient. Streaks are smooth and not associated with dystrophic changes. The following 4 pigmentary presentations have been described:
  • One longitudinal band per nail, 1-8 mm in thickness
  • Two longitudinal bands per nail, 1-8 mm in thickness, which tend to occur along the lateral aspects of the nail plate
  • Half nail pigmentation
  • Complete nail pigmentation
• The Hutchinson sign, defined as the extension of pigment onto the proximal nail fold, is characteristically believed to be an ominous finding associated with spreading malignant melanoma. However, a pseudo-Hutchinson sign has been reported in multiple patients with LHS,^14,15 sometimes on various nails of the same patient. Pigment may also involve the lateral nail folds.
• Extended mucocutaneous pigmentation has become a recognized feature of LHS.¹⁶ Melanotic macular hyperpigmentation has been observed on the neck, the thorax, the abdomen, the dorsal and lateral aspects of the fingers, the palms and soles, the genitalia, the perineum, the perianal skin, and the anal mucosa of patients with LHS. Patients with LHS involving the conjunctiva, sclera, and esophageal mucosa have also been reported.^1,3,17

The etiology of melanosis in LHS is unknown.

Treatment

Treatment is not required, but a workup to rule out the other entities in the differential may be necessary.

Q-switched Nd:YAG¹⁴ or Q-switched alexandrite laser therapy may be an effective option for cosmetically bothersome melanosis on the skin. Recurrence after treatment has been reported, and sun protection is thought to be helpful in preventing recurrence.²¹ Cryosurgery has also been described, with good results.²²