Immunohistochemical Expression of TGF-β1 in Lichen Planus

Lichen planus related to transforming growth factor beta inhibitor in a patient with metastatic chondrosarcoma: a case report

Transforming growth factor-beta1 (TGF-β1) is expressed in normal epidermis. TGF-β1 potently inhibits keratinocyte proliferation and immunomodulatory properties, mainly by suppressing immune responses to self-antigens. Lichen planus (LP) is a form of dermatitis caused by cell-mediated immune dysfunction, but the exact pathogenic pathways are unknown, which poses therapeutic challenges. We report on a 68-year-old man who developed multiple pruritic, discrete, and well-demarcated, flat-topped red-purple papules and macules on the back and upper arms following 4 cycles of treatment with TGF-β receptor I (TGFBR-I) inhibitor, ly3200882, for metastatic chondrosarcoma. The biopsy showed hyperkeratosis, wedge-shaped hypergranulosis, elongation of the rete ridges, and a dense band-like lymphohistiocytic infiltrate admixed with colloid bodies and pigment incontinence, consistent with LP. Temporal correlation suggested that the TGFBR-I inhibitor might be a trigger. Treatment with topical clobetasol and oral metronidazole led to partial resolution of the lesions with postinflammatory hyperpigmentation. We believe this is the first reported case of LP related to TGFBR-I inhibitor therapy. This report expands the list of cutaneous adverse events associated with this novel class of targeted therapy. More importantly, this report supports emerging evidence that failure of TGF-β1 activation/signal transduction is an important mechanism in the pathogenesis of LP and suggests the TGF-β1 pathway as a potential therapeutic target in this disease.

Lichen planus and lichenoid dermatoses: Clinical overview and molecular basis

Deriving from the Greek word λειχήν for "tree moss" and the Latin word planus for "planar," lichen planus is a relatively uncommon and heterogeneous cutaneous disorder that typically develops in middle-aged adults. Despite the significant clinical burden associated with the disorder, little well-conducted molecular research has been undertaken, possibly because of heterogeneity impeding consistent and confident phenotyping. The multiple variants of lichenoid disease bear overlapping clinical and pathologic features despite manifesting as distinct clinical disorders. The first article in this 2-part continuing medical education series provides a comprehensive overview of the clinical and pathologic characteristics of cutaneous lichenoid dermatoses and links these manifestations to recent advances in our understanding of the underlying pathobiology of such diseases.