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.