Lung adenocarcinoma presenting with eosinophilic erythroderma associated with anti‐KRT6B antibodies: Case report

Abstract Paraneoplastic erythroderma (PE) is a rare and potentially life‐threatening inflammatory condition associated with malignancy. PE may potentially develop due to antibodies produced against tumoral antigens that cross‐react with epidermal structures. We report a patient with paraneoplastic eosinophilic erythroderma associated with lung adenocarcinoma. Erythroderma and eosinophilia subsided after wedge‐resection of the tumour. To tackle the pathogenesis of PE in this patient, we performed western blot analysis (WB) using healthy human skin tissue lysate and the patient's serum. Samples were analysed first by immunoprecipitation of autoantibody‐target protein complexes and mass spectrometry to reveal the corresponding protein. After incubating patient serum with skin proteins, in WB, we could observe a distinct band around 60 kD. Later, immunoprecipitation for mass spectrometry showed a bar in the same area which was not present in healthy controls. Mass spectrometric analysis revealed that KRT6B might be the potential target protein. In this patient with PE, which resolved after surgical removal of lung adenocarcinoma, the antibody production to tumoral antigens cross‐reacting with keratins in skin may have initiated the dermatitis.