[Mycoplasma pneumoniae pneumonia with diffuse nodular shadows and right hilar lymphadenopathy]

A 51-year-old man was admitted to our hospital because of fever, a productive cough, and dyspnea. His chest X-ray film revealed diffuse reticulonodular shadows and right hilar lymphadenopathy. A chest CT scan revealed thickened bronchial walls and diffuse centriacinar or centrilobular nodular shadows. Serologic testing provided conclusive evidence of Mycoplasma pneumoniae infection. The diffuse pattern and hilar lymphadenopathy on chest X-ray films are uncommon in this disease, and they caused some uncertainty regarding the correct diagnosis. M. pneumoniae attaches to cells of the respiratory tract and produces a locally acting cytotoxin. Immunologic mechanisms have been shown to play an important role in the pathogenesis of pneumonia. This case suggests that immunologic mechanisms are an important factor in diffuse lung lesions.