Osimertinib-associated ashy dermatosis–like hyperpigmentation

Osimertinib is an oral, third-generation epidermal growth factor receptor (EGFR)–tyrosine kinase inhibitor (TKI). It is approved for patients with advanced non–small-cell lung cancer who have disease progression despite the administration of the first- or second-generation EGFR-TKI by acquiring a second mutation in exon 20 of the EGFR T790M.1\r\n\r\nEGFR plays a pivotal role in maintaining skin homeostasis. Therefore, dermatologic adverse events (dAEs) commonly occur during the course of EFGR-TKI therapy that specifically inhibits this pathway. Common manifestations include papulopustular eruptions, pruritus, paronychia, hair changes, and xerosis. However, pigmentary changes in association with EGFR-TKI treatment are rarely reported.2 Here, we describe an unusual case of slate gray hyperpigmentation associated with osimertinib therapy.