DESQUAMATIVEINTERSTITIAL PNEUMONITIS AND LEUKEMIA 321 Desquamative Interstitial Pneumonitis Associated with Monomyelocytic Leukemia*

D esquamative interstitial pneumonitis ( DIP) is an inflammatory process in the lung characterized histologically by massive accumulation of intra-alveolar mononuclear cells, predominantly alveolar macrophages ( PAMs ) , without necrosis, fibrin exudates, hyaline membranes, or extensive fibrosis.1’2 Whether DIP is a distinct clinicopathologic entity or is merely part of a spectrum of fibrosing alveolitis remains controversial;3 however, patients with DIP tend to respond better to glucocorticoids, progress to “honeycomb lung” less frequently, and survive longer than patients with usual interstitial pneumonitis ( UIP ).4 The etiology of DIP is unknown, but more than one cause is likely since a variety of associated diseases and conditions have been noted in scattered cases.512 This report describes two patients with a previously unknown association-DIP and monomyelocytic leukemia. The findings in these cases provide additional evidence that alveolar macrophages and their precursors are still capable of responding to inflammatory stimuli even in the presence of hematologic malignancy.