Two Cases of Lichen Planus Pigmentosus Presenting with a Linear Pattern

Abstract

We report two cases of lichen planus pigmentosus (LPP) that developed in a unilateral linear pattern. The patients presented with unilateral linear brown macules on the extremities. Skin biopsy showed orthokeratosis, basal hydropic degeneration with scarce lymphohistiocytic infiltrates, and numerous melanophages in both patients. These patients, to the best of our knowledge, are the first cases of LPP presenting with a linear pattern. LPP should be considered in the differential diagnosis of linear hyperpigmented skin lesions.

Linear lichen planus pigmentosus and coincidental ipsilateral facial nerve palsy: An unusual observation

“…The relation of EDP to lichen planus (LP) is uncertain, both have several clinical, histological and immunohistochemical similarities and often coexist, making some authors consider EDP a variant of LP [11]. Linear LPP is considered as a combined type of linear lichen planus and LPP and there have been only a few reports on this in the dermatologic literature [12][13][14][15], especially from India [16]. The linearity of the lesion is probably related to Blaschko's lines, which suggests that the predisposition to develop LPP might be determined during embryogenesis [2].…”

A Case of Linear Lichen Planus Pigmentosus

“…Based on the distinctive lymphocytic inflammatory response of the lichenoid reactions, cell mediated immunity seems to play a pivotal role in triggering the clinical expression of the disease. T-lymphocytes are pivotal as they regulate epidermal cell recognition, the lichenoid response and epithelial destruction [2][3][4]8 . Clinically, LPP differs from classical lichen planus by exhibiting dark brown macules and/or papules and a longer clinical course 2 .…”

“…LPP is characterized by mottled or reticulated hyperpig- mented, dark brown macules on the sun exposure skin areas and flexural folds on the face and neck, and the axillae and inguinal regions [1][2][3] .…”

“…A perivascular lymphohistiocytic infiltration and pigmentary incontinence in the dermis are also noted 2,6 .…”

“…Lichen planus pigmentosus (LPP) was first described by Bhutani et al 1 , and this a rare variant of lichen planus, and LPP appears as mottled or reticulated hyperpigmented, dark brown macules or papules on the sun exposed areas and flexural folds 2,3 . Linear lichen planus, which shows a linear distribution following Blaschko's lines, is considered a subtype of lichen planus [3][4][5] .…”