下葉優位で特発性間質性肺炎との鑑別を要したサルコイドーシスの1例

Pulmonary sarcoidosis manifesting as lower-lobe predominant reticulation：a case report

サルコイドーシスは，原因不明の全身性疾患で，類上皮細胞肉芽腫によって病理学的に特徴づけられる。肺サルコイドーシスでは，20％程度に線維化の所見がみられ，線維化の分布は上肺野に多い^1）2）。今回，下肺野優位の線維化所見を呈し，画像診断では特発性間質性肺炎との鑑別が困難だった症例を報告する。

A woman in her 70 s presented with dyspnea. Chest computed tomography showed subpleural and basal predominant reticular opacities, suggesting idiopathic interstitial pneumonia, especially interstitial pulmonary fibrosis（IPF）. Micronodules were also observed. Transbronchial lung cryobiopsy from the lower lobe revealed non-necrotizing epithelioid granulomas consistent with sarcoidosis. No extrapulmonary lesion was detected. After the disease progression during months of observation, we administered oral glucocorticoid therapy. The pulmonary infiltrates decreased following the therapy. In conclusion, although lower-lobe predominance suggests IPF, concomitant micronodules may give a clue to diagnosing sarcoidosis. Sarcoidosis with atypical fibrotic lesions may also respond to corticosteroid therapy.