[A case of chronic interstitial pneumonia with benign monoclonal gammopathy (IgM-k) and thrombocytopenia].

A 53-year-old woman was admitted on 13th October 1988 with symptoms of dry cough and shortness of breath persisting for 1 year. On physical examination, fine crackles were audible over her back. Chest X-ray showed bilateral reticulonodular shadows and collapse of the bilateral lower lobes. Chest CT showed patchy areas of increased density distributed predominantly in the subpleural zone. Laboratory data on admission showed thrombocytopenia, hypergammopathy (IgG, 2044 mg/dl; IgA, 286 mg/dl; IgM, 1645 mg/dl), and positive ANF. Further examinations demonstrated that anti-platelet and anti-centromere antibodies were positive in the serum, and the titer of PA-IgG was high (56 ng/10(7) platelets). Histopathological examination of the open lung biopsy demonstrated honeycombing and thickening of the alveolar walls, with slight infiltration of chronic inflammatory cells. These histopathological findings were comparable with usual interstitial pneumonia. We report a very rare case of chronic interstitial pneumonia complicated by benign monoclonal gammopathy and thrombocytopenia. Although it remains unclear, these abnormalities may have been caused by immunological mechanisms.