JAAD Grand Rounds quiz. Numerous hyperpigmented macules of the oral mucosa

Mystery behind labial and oral melanotic macules: Clinical, dermoscopic and pathological aspects of Laugier-Hunziker syndrome

Labial and oral melanotic macules are commonly encountered in a broad range of conditions ranging from physiologic pigmentation to a sign of an underlying life-threatening disease. Although Laugier-Hunziker syndrome (LHS) shares some features of labial and oral pigmentation with a variety of conditions, it is a benign and acquired condition, frequently associated with longitudinal melanonychia. Herein, the demographic, clinical, dermoscopic, and pathological aspects of LHS were reviewed comprehensively. The important differential diagnoses of mucocutaneous and nail pigmentation are provided. An accurate diagnosis is crucial to design a reasonable medical strategy, including management options, malignant transformation surveillance, and psychological support. It is important that clinicians conduct long-term follow-up and surveillance due to the potential risks of malignant transformation and local severe complications in some conditions.

Laugier-Hunziker syndrome: a case of asymptomatic mucosal and acral hyperpigmentation

Laugier-Hunziker syndrome (LHS) is a rare condition characterized by acquired hyperpigmentation involving the lips, oral mucosa, acral surfaces, nails and perineum. While patients with LHS may manifest pigmentation in all of the aforementioned areas, most present with pigmentation localized to only a few of these anatomical sites. We herein report a patient exhibiting the characteristic pigment distribution pattern associated with LHS. Since LHS is a diagnosis based on exclusion, we discuss the differential diagnosis of mucocutaneous hyperpigmentation. Due to the benign nature of the disease, it is critical to differentiate this disorder from conditions with similar mucocutaneous pigmentary changes with somatic abnormalities that require medical management. We also explore potential mechanisms that may explain the pathogenesis of LHS.