Severe paraneoplastic peripheral blood eosinophilia and eosinophilic malignant pleural effusion as rare manifestations of squamous cell carcinoma lung

摘要

Introduction: Approximately 5%-8% of all exudative pleural effusion is eosinophilic effusion which is defined as presence of 10% or more eosinophils in pleural fluid. Presence of both peripheral blood eosinophila and eosinophilic pleural effusion in the same patient with bronchogenic carcinoma is very rare. This has prompted us to report this case of bronchogenic carcinoma with severe peripheral blood eosinophilia and eosinophilic pleural effusion. Clinical note: A 52 year old male, smoker, non-diabetic, normotensive, businessman presented with clinico-radiological features of right sided massive pleural effusion. Initially, total leucocyte count was 31500/??l (18% Eosinophils) and absolute eosinophil count was 5670/??l. Within a span of two weeks his total leucocyte count raised to 86500/??l (77% eosinophils) and absolute eosinophil count raised to 66605/??l. Pleural fluid was exudative in nature with presence of significant eosinophils (Total cells 1000/??l, Eosinophils 15%, absolute eosinophil count in pleural fluid 150/??l). He was thoroughly investigated for causes of increased peripheral and pleural fluid eosinophil count including bone marrow trephine biopsy and karyotyping which were normal. Translocation of bcr-abl gene and FIP1L1-PDGFRA gene were also negative. Histopathological examination of pleural biopsy tissue revealed metastatic squamous cell carcinoma. A final diagnosis of metastatic squamous cell carcinoma of lung with paraneoplastic peripheral eosinophilia and eosinophilic malignant pleural effusion was made. Discusion: Eosinophilia in solid malignancies is uncommon and rarely reported in carcinoma of lung. The pathogenesis of eosinophilia in bronchogenic carcinoma is poorly understood. The finding of markedly increased pleural as well as peripheral eosinophil in this patient is attributed to lung tumour and is not a manifestation of eosinophilic leukaemia (mature eosinophils in the bone marrow and peripheral blood without any blast cell), hypereosinophilic syndrome (absence of FIP1L1-PDGFRA gene) or eosinophilic variety of CML (absent bcr-abl translocation). Usually, eosinophilia in association with bronchogenic carcinoma has an aggressive course and very poor prognosis. Hypereosinophilia may have some yet unrecognized immunomodulatory factors. Conclusion: Lung carcinomas can present with different paraneoplastic syndromes. But the presence of marked peripheral blood eosinophilia as well as eosinophilic pleural effusion in lung carcinoma is quite rare and it needs exclusion of other causes of eosinophilia. The reasons for this paraneoplastic manifestation of eosinophilia in lung cancer is not clearly understood and further studies are required. ? 2013 Japan International Cultural Exchange Foundation & Japan Health Sciences University.