Differential Diagnosis of Non-specific Interstitial Pneumonitis

Abstract

THE terms “pneumonitis” and “pneumonia” are synonymous; both may be defined as “inflammatory disease of lung parenchyma.” Many pathologists, however, reserve “pneumonitis” for use in designating pneumonia of the chronic interstitial fibroid type, which may be encountered under a wide variety of clinical circumstances. As a result, “pneumonitis” has acquired an implied limitation of meaning. Although lobar pneumonia in its classical form is, strictly speaking, a form of pneumonitis, the distinctive clinical and radiologic features of this disease justify its specific designation as lobar pneumonia by the radiologist. Likewise, in the majority of instances pulmonary tuberculosis can be identified radiologically with a reasonable measure of confidence. It is only when the telltale signs characteristic of some particular pathologic process are lacking that the radiologist feels the desire to avail himself of the latitude which the widely inclusive term of “pneumonitis” implies. Chronic inflammatory processes ...