Purpose: The aim of this study was to assess the CT findings of pulmonary involvement in patients with idiopathic hypereosinophilic syndrome (HES).
Method: The study included five patients with idiopathic HES who had pulmonary involvement proven by bronchoalveolar lavage (n = 3) or based on clinical and radiologic findings (n = 2). Four patients had high resolution CT and one had conventional CT. The CT scans were retrospectively reviewed by two chest radiologists for pattern and distribution of disease.
Results: All five patients had several small nodules in both lungs at CT scan. Four patients had nodules with a halo of ground-glass attenuation. Three patients had focal areas of ground-glass attenuation in both lungs. These lesions were present in all lung zones and involved mainly the peripheral lung. There was neither lobar predilection nor peribronchovascular distribution. Other organs involved included bone marrow (n = 3), liver (n = 3), stomach (n = 1), and peritoneum (n = 1).
Conclusion: The CT findings of pulmonary involvement in patients with idiopathic HES included small nodules with or without a halo of ground-glass attenuation and focal areas of ground-glass attenuation mainly in the lung periphery.