Lichen planus pigmentosus (LPP) is a condition characterized by persistent and asymptomatic brownish-black-to-blue or purple-gray pigmentation, predominantly in the face and sun-exposed areas, commonly in dark-skinned individuals. Several clinical variants of LPP have been reported. However, the ichthyosiform type of LPP has not been reported. We present a 19-year-old male patient who presented with a 7-year history of asymptomatic grayish macules; patches with fine scales on the face, trunk, and upper extremities; and grayish plaques with thick "ichthyosiform" scales on the lower extremities. The diagnosis of LPP was proven by histopathological findings on both the macular and ichthyosiform plaques. Cluster differentiation (CD) 68 stain highlights the same density of pigment-laden macrophages in both the gray macule and the ichthyosiform plaque. The cause of LPP is unknown. Transcription factor anomalies may play a role in increased keratinization of lichen planus lesions. It can be assumed that the mechanism of the altered distribution of keratinization may occur on the ichthyosiform lesions in this patient. The terminology "ichthyosiform lichen planus pigmentosus" is hereby proposed to be added to the clinical variants of LPP.
Keywords: Filipino; Pacific Island; asymptomatic; clinical; dermatologist; dermatology; diffuse; hyperpigmentation; hypersensitivity; ichthyosiform; lichen planus pigmentosus; pigmentary disorder; pigmentation; skin; sun; sun exposed; sunburn.
©Audi Sugiharto, Julius Gatmaitan, Johannes Dayrit. Originally published in JMIR Dermatology (http://derma.jmir.org), 19.04.2024.