Eosinofiele fasciitis na immuuncheckpointinhibitie met pembrolizumab

Eosinophilic fasciitis following checkpoint inhibitor therapy with pembrolizumab A 70-year-old woman presents with progressive induration of the skin and oedema spreading to the 4 limbs. She has been treated for 8 months with pembrolizumab for a stage IVa non-small-cell adenocarcinoma of the right lung. A blood test reveals eosinophilia. The MRI of the left forearm shows oedematous thickening of the superficial and deep intermuscular fascia, consistent with fasciitis. On the biopsy, fascial thickening and accumulation of lymphocytes is observed. The diagnosis of eosinophilic fasciitis is made, presumably triggered by pembrolizumab. After multidisciplinary consultation at the Belgian Multidisciplinary Immunotoxicity Board (BITOX), the treatment with pembrolizumab is discontinued. The patient is administered methylprednisolone 1 mg/kg and achieves complete remission of the symptoms.