[An autopsy case of non-specific interstitial pneumonia].

An autopsy case of fibrotic non-specific interstitial pneumonia (NSIP) is herein reported. A 54-year-old woman was admitted to our hospital because of dry cough and fever that had continued for a month. Her chest radiograph showed diffuse reticular shadows in both lower lung fields. Analyses of bronchoalveolar lavage fluid (BALF) showed an increase in the percentage of lymphocytes and a decrease in CD4/CD8 ratio. Video-assisted thoracoscopic (VATS) lung biopsy revealed that she had fibrotic NSIP. She was treated with corticosteroid with a transient increase in vital capacity, but her condition gradually deteriorated, associated with a decrease in lymphocytes and an increase in CD4/CD8 ratio shown by repeated measurement of BALF. She died 6 years after the diagnosis. The autopsied lungs showed diffuse consolidated lesions predominantly in both lower lung fields, without honeycombing. Histologically, the lung parenchyma was diffusely involved with homogeneous fibrosis, compatible with fibrotic NSIP. However, mononuclear cell infiltration was less severe, and collagen deposition was more extensive than shown by the VATS specimen. There is a possibility that the CD4/CD8 ratio in BALF may reflect the severity of fibrosis in the lung parenchyma. Histological differences between autopsy and biopsy specimens in this case could help to elucidate the natural course of fibrotic NSIP.