The possible similarity of lipid pneumonia to pulmonary neoplasms from the roentgenologic and clinical aspects has been mentioned in publications describing the production of acute and chronic pulmonary lesions by lipids in infants, children and adults.1The clinical and pathologic features of lipid pneumonia in infancy and childhood have gained widespread recognition, but the lesions that occur in adults are extremely variable and have not been so well defined. The case to follow, of localized lipid pneumonia simulating a pulmonary neoplasm in an adult, is the first recorded instance of a surgical cure of this condition. The surgical therapy came about by chance, and it seems to us, in retrospect, that the diagnosis of lipid pneumonia could possibly have been made earlier in the case reported herewith. A complete preliminary study suggested a malignant condition of the lungs to be the most likely diagnosis. Operative intervention with lobectomy in