We report a case of hypersensitivity pneumonitis in a worker cultivating enoki mushrooms. The patient developed symptoms of cough, sputum, and dyspnea after changing the culture medium of the enoki mushrooms. Radiographic findings showed small nodules and ground glass opacity in both lung fields. Bronchoalveolar lavage revealed a marked increase in lymphocytes. Lymphocyte stimulation test in both blood and bronchoalveolar lavage were positive for the culture medium but not for enoki mushrooms. Based on the results, a diagnosis of hypersensitivity pneumonitis caused by the culture medium of enoki mushrooms was confirmed. We should consider that the culture medium is a possible antigen leading to hypersensitivity pneumonitis.
