Clinical characteristics of eosinophilic organ involvement distinguishing from metastasis in cancer patients with eosinophilia

Background: Eosinophilic organ involvement should be differentiated from metastasis of primary cancer, when space occupying lesions were newly developed together with peripheral blood eosinophilia in a patient who has been diagnosed with cancer, because further chemotherapy may be needed.

 Objective: To investigate clinical characteristics of eosinophilic organ involvement compared with distant metastasis in patients with primary cancer.

 Methods: We retrospectively reviewed medical records of thirty cancer patients who newly developed hepatic or pulmonary nodules with peripheral blood eosinophilia from January, 2005 to February, 2010 in Asan Medical Center in Seoul. Eosinophilic infiltration or distant metastasis was defined by pathologic findings and radiologic features. Mann-Whitney U test or Kruskal-Wallis test were used for statistical analysis.

 Results: Twenty patients (66%) were diagnosed with eosinophilic infiltration, 5 (17%) with cancer metastasis, and 5 (17%) with undetermined. History of raw food diet, high serum levels of total IgE, normal liver function test, fewer and smaller nodules were significantly associated with eosinophilic infiltration rather than metastasis. Causes of eosinophilic infiltration were parasite infection (n=15), drug (n=1) and undetermined (n=14).

 Conclusion: Our results suggest that eosinophilic organ infiltration has distinguished clinical characteristics compared with cancer metastasis. Moreover, physicians need to have more efforts to find the causes of organ involvement with peripheral blood eosinophilia, especially in cancer patients.