Hypereosinophilic syndrome in the differential diagnosis of pulmonary infiltrates with eosinophilia.

OBJECTIVE

To describe key diagnostic considerations in patients with pulmonary infiltrates with eosinophilia, with a special emphasis on raising awareness of hypereosinophilic syndrome (HES), a disease that often involves the lungs and prompts investigation for clonal neoplastic processes that determine prognosis and treatment.

DATA SOURCES

Studies and review articles were selected from PubMed and Scopus for relevance to pertinent topics.

STUDY SELECTIONS

The literature was screened for studies that described lung eosinophilia and HES. Studies relevant to the topic were included in this review.

RESULTS

Pulmonary eosinophil infiltrates in lung biopsy specimens present a broad differential diagnosis, including eosinophilic pneumonia; hypersensitivity reactions, such as allergic bronchopulmonary fungal disease; and pulmonary manifestations of systemic diseases, such as eosinophilic granulomatosis with polyangiitis. An additional important consideration in the differential diagnosis is pulmonary involvement by HES. HES is a rare syndrome that comprises a heterogeneous group of conditions characterized by persistent blood and/or tissue eosinophilia associated with organ dysfunction. Approximately one-third of HES cases are caused by neoplastic diseases, with the remaining cases classified as reactive or idiopathic. Lung involvement is seen in up to 67% of cases and may be the presenting manifestation of the disorder.

CONCLUSION

The differential diagnosis of pulmonary eosinophilia is broad and requires a multidisciplinary approach with clinicopathologic-radiologic correlation.