Eosinophils engulfing platelets and with ring-shaped nuclei in nivolumab-associated eosinophilia.

Abstract

A 63-year-old male smoker had been diagnosed with stage IVTTF1+( thyroid transcription factor -1) lung adenocarcinoma oneyear ago. Four cycles of carboplatin and pemetrexed were admin-istered without response. Thereafter, he was treated with nivolu-mab 240 mg intravenously every two weeks. Following thesecond cycle, eosinophilia was detected for which no other causewas found. A partial response of the cancer was achieved andtreatment was continued despite asymptomatic and progressiveeosinophilia which reached a maximum of 1039109/l eosino-phils after the tenth nivolumab cycle. Examination of the periph-eral blood film showed eosinophils with ring-shaped nuclei (1–2/1000) (bottom) and platelet phagocytosis by eosinophils (<1/1000) (top). Cytopenias were not detected. Despite treatmentwith prednisone 30 mg/day, eosinophilia persisted (719109/l)but with no associated clinical symptoms. PDGFRA, PDGFRB ,FGFR1 and JAK2 rearrangements were negative