Detection of ETosis in the Lesion of Eosinophilic Fasciitis

Abstract

A 59-year-old man presented to our department with a 3-month history of worsening swelling in extremities and erythema on the forearms. On initial examination, swelling and sclerosis were observed in both upper and lower limbs, along with an orange-peel-like appearance on the forearms. Blood tests revealed peripheral eosinophilia, and MRI showed high-signal areas along the fascia. Histopathological examination revealed fascia thickening and eosinophilic infiltration, leading to a diagnosis of eosinophilic fasciitis. Treatment with oral prednisolone at 35 mg/day resulted in symptom improvement. The dose has since been tapered to 12.5 mg/day without recurrence. Immunofluorescence using galectin-10 and major basic protein (MBP) revealed ETosis in the lesion of eosinophilic fasciitis.