Autoimmune Dermatosis in a Pembrolizumab-Treated Patient With Merkel Cell Carcinoma: Case Study
Posted: Monday, October 19, 2020
In a case study published in JAAD Case Reports, a team of investigators, led by Benjamin K. Stoff, MD, MA, of Emory University School of Medicine, Atlanta, reported on a female patient being treated with pembrolizumab for metastatic Merkel cell carcinoma who developed the autoimmune dermatosis known as lichen planus pemphigoides. Of note, cutaneous toxicities are among the most common adverse events that may arise with immune checkpoint inhibitors.
The patient, a 65-year-old woman with widely metastatic Merkel cell carcinoma to the brain, lungs, and subcutaneous tissue, had completed seven cycles of pembrolizumab. She presented to an outpatient dermato-oncology clinic with a diffuse pruritic rash. Her pruritus developed within 1 week of initiating treatment with pembrolizumab (200 mg intravenously, every 3 weeks) and continued to progress with each cycle. At the clinic visit, physical examination was notable for numerous erythematous-to-violaceous, hypertrophic, lichenified papules and plaques scattered on the dorsal hands, forearms, chest, upper back, lower extremities, and dorsal feet bilaterally.
Given the extent and severity of the patient’s cutaneous toxicity, pembrolizumab was discontinued. The patient was treated with a 3-week course of an oral prednisone taper, starting at 40 mg, supplemented by clobetasol 0.05% ointment twice daily. Her pruritus rapidly resolved, and her skin lesions began to resolve rapidly, with secondary changes gradually fading over 6 months. The authors noted that unless the cutaneous toxicity is life-threatening, immunotherapy does not need to be permanently discontinued, although the toxicity may recur upon resuming checkpoint inhibitor therapy.
“With increased recognition of immunotherapy-induced carcinoma lichen planus pemphigoides, more data can be collected about patient outcomes, including identification of treatments that allow for the resolution of carcinoma lichen planus pemphigoides while maintaining the tumor response achieved by the immunotherapeutic agents,” concluded the authors.
Disclosure: For full disclosures of the study authors, visit jaadcasereports.org.