By performing autopsies in the fatal cases in this population we could determine that the cause of death in all patients was extensive involvement of the lungs and alterations secondary to multiple organ failure in major organs such as kidney and liver [11] . Patients had severe DAD associated with severe NB and alveolar hemorrhage. Further, autopsy results showed that patients had metastatic disease and signs of cellular immunosuppression as depletion of white pump view on spleen analysis. Certainly, autopsies contributed to a better characterization of these patients. This report has some limitations. The unicentric characteristics of the study and the small sample size do not allow for definite conclusions about severe H1N1 presentation in oncologic patients. We characterized H1N1 infection in a selected population of patients with neoplasm, with a high incidence of metastatic disease and who needed ICU care. Our findings certainly describe the most serious presentation of disease.