Intrathoracic Rhabdoid Tumors Showing Rapid Progress in Patients with a History of Immune-suppressive Therapies for Hematological Diseases.

We herein report 2 autopsied cases of intrathoracic undifferentiated/rhabdoid neoplasms showing rapid progress in patients who received immunosuppressive therapies for hematological diseases (Case 1, a 72-year-old man who underwent hematological cell transplantation for aplastic anemia; Case 2, a 77-year-old man who received chemotherapy for multiple myeloma). Both patients experienced progressive pulmonary effusion and died after three months and two weeks of follow-up, respectively. Autopsy revealed rhabdoid neoplasms infiltrating the alveolar spaces in both cases. Nuclear immunoreactivity for SMARCB1/INI1 was lost in Case 2. Clinicians and pathologists should consider the possibility of rapidly progressive neoplasms, such as intrathoracic undifferentiated/rhabdoid neoplasm, as a differential diagnosis for pneumonia in possible immunosuppressive conditions.