[An autopsy case of lymphoid interstitial pneumonia with monoclonal gammopathy].

An autopsy case of a 75-year-old female with lymphoid interstitial pneumonia with monoclonal gammopathy of IgA kappa type is reported. The patient was admitted to UOEH Hospital suffering from a cough, sputum and fever. After examining a specimen of transbronchial lung biopsy and chest X ray films, lymphoid interstitial pneumonia was suspected. Serum immunological examination showed monoclonal IgA kappa type hypergammaglobulinemia. Marked clinical and radiological improvement was attained after prednisolone administration. After 16 months, however, the patient deteriorated and expired on January 21, 1986. On postmortem examination, a number of plasma cells as well as lymphoid cells were seen to have infiltrated in the thickened interalveolar septa and the parenchyme of the lymph nodes throughout the whole body. The architecture of lymph nodes remained preserved, while the cortex as well as the medulla was almost completely replaced by plasma cells and lymphoplasmacytoid cells. Immunohistochemical examination demonstrated the presence of IgA kappa in the plasma cells and some of the lymphoplasmacytoid cells in both lymph nodes and lungs. These findings suggest that the proliferating plasma cells and lymphoplasmacytoid cells were in neoplastic or preneoplastic states and support the hypothesis that lymphoid interstitial pneumonia may be an expression of the systemic lymphoproliferative disorders in the lung.