Summary

We report a case of a 90-year-old man with hypereosinophilia, lymphadenopathies and skin lesions, namely lichenification and pruritus. An aetiological investigation was performed, and a bone marrow (BM) biopsy and aspirate showed a hypercellular marrow with hypereosinophilia without dysmorphia or abnormal elements, and the BM and inguinal node’s immunophenotyping denied any presence of abnormal lymphoid cell population. The inguinal node biopsy revealed a multinodular proliferation of large cells S100 and CD1a⁺, and a diagnosis of Langerhans cell histiocytosis was made. The hypereosinophilia and skin lesions were managed with corticotherapy with substantial improvement of cutaneous lesions and lymphadenopathies and normalisation of eosinophil count. Finally, to define if it is a single or multisystem disease, a skin biopsy will be necessary.