TY - BOOK AU - Cardis, Michael A TI - Diffuse lichen planus-like keratoses and clinical pseudo-progression associated with avelumab treatment for Merkel cell carcinoma, a case report SN - 1471-2407 PY - 2019/// KW - *Antibodies, Monoclonal/ae [Adverse Effects] KW - *Antibodies, Monoclonal/tu [Therapeutic Use] KW - *Antineoplastic Agents/ae [Adverse Effects] KW - *Antineoplastic Agents/tu [Therapeutic Use] KW - *Carcinoma, Merkel Cell/dt [Drug Therapy] KW - *Keratosis/et [Etiology] KW - *Lichen Planus/pa [Pathology] KW - *Skin Neoplasms/dt [Drug Therapy] KW - Aged KW - Antibodies, Monoclonal/ad [Administration & Dosage] KW - Antibodies, Monoclonal/pd [Pharmacology] KW - Antineoplastic Agents/ad [Administration & Dosage] KW - Antineoplastic Agents/pd [Pharmacology] KW - B7-H1 Antigen/ai [Antagonists & Inhibitors] KW - Cryotherapy KW - Disease Progression KW - Glucocorticoids/tu [Therapeutic Use] KW - Humans KW - Keratosis/dt [Drug Therapy] KW - Keratosis/im [Immunology] KW - Male KW - Positron Emission Tomography Computed Tomography KW - Programmed Cell Death 1 Receptor/ai [Antagonists & Inhibitors] KW - Treatment Outcome KW - Triamcinolone/tu [Therapeutic Use] KW - MedStar Washington Hospital Center KW - Dermatology KW - Journal Article N2 - BACKGROUND: Avelumab is an anti-programmed cell death ligand 1 (PD-L1) antibody approved for treatment of Merkel cell carcinoma (MCC) and locally advanced or metastatic urothelial carcinoma. It shares a similar side effect profile to other immune checkpoint inhibitors, including immune-related adverse reactions in the skin. These adverse skin reactions can present as a morbilliform exanthem, lichenoid dermatitis, vitiligo, autoimmune bullous disorder, among others; CASE PRESENTATION: We describe a patient with advanced MCC successfully treated with avelumab who developed acute onset diffuse lichen planus-like keratoses (LPLK) at sites of existing seborrheic keratoses (SK) and lentigines. Histopathology of an affected SK revealed papillomatous epidermal hyperplasia with lichenoid interface changes, numerous dyskeratotic keratinocytes and intermittent hypergranulosis. The findings resembled lichen planus (LP) arising in an SK. Onset of the skin symptoms corresponded with an inflammatory cancer response (clinical pseudo-progression), and the eruption improved as overall tumor burden decreased. The patient's pruritus was treated with topical steroids and cyrotherapy for individual symptomatic lesions; CONCLUSION: Diffuse LPLK is a distinct immune-related reaction pattern associated with PD-L1/PD-1 checkpoint blockade. This is an important side effect to be aware of as LPLK frequently mimic keratinocytic neoplasms. Further observation is needed to assess the prevalence and significance of this immune therapy-associated adverse reaction UR - https://dx.doi.org/10.1186/s12885-019-5759-1 ER -