Pulmonary Cysts

Abstract

BEFORE presenting this unusual and interesting case of pulmonary cysts, I would like to make a few preliminary remarks. A diagnosis of liver abscess was made in 1929. A retrograde pyelogram of the right kidney made in September, 1936, revealed an anomalous bifid renal pelvis and a moderately enlarged kidney. A roentgenographic examination, in September, 1936 (Figs. 5 and 6) revealed an enlarged liver having a smooth lower border and fairly well filling up the entire right abdomen. Its enlargement also pushed the gas-containing loops of intestines well over into the left half of the abdomen. Of what did the enlargement consist? Was it carcinoma, hydatid cyst, or some other form of neoplasm? Unfortunately, an autopsy was not available. The subject in question will be treated mainly from a roentgenologic standpoint. There is no question about the existence of cysts. The thing to be determined is, how do these cysts take origin and what appearance do they present roentgenologically at their inception? Unfortunately, the latter question cannot be answered because the cysts were not seen at their earliest stage. Obviously, a cyst which contains fluid, as ordinarily it will at its inception, would present itself on the roentgenograph as a circular or oval, smoothly outlined area of marked homogeneous density. An air-containing cyst would present a sharply defined circular or oval-shaped linear density confining within itself an area of radiability or translucency. An intermediate stage would present itself in a manner highly suggestive of that occasioned by a pulmonary abscess in which there is a fluid level. That is, the lower portion of the cyst would be dense and the upper, air-containing portion, markedly rarefied or translucent. Do all cysts at their inception contain fluid? The majority opinion is that they do. I believe, however, there is a fair agreement of opinion that the congenital type of cyst may present itself as an air-containing proposition or a fluid-containing —usually the latter. During the process of early development of the pulmonary tissue, the cystic portions may have remained in contact with an open bronchus, thereby resulting in an air-containing cyst, or they may have developed from, and later become independent of, the contributing bronchus, thereby resulting in a fluid-containing cyst. With regard to the hydatid cyst, it will first manifest itself as a rounded area of marked homogeneous density until such time as suppuration has set in. After perforation of a bronchus has resulted, an air communication is established between these structures. It is at this time that the roentgenologist would be puzzled in differentiating between a pulmonary abscess cavity containing fluid and a cyst. There does not appear to be much chance of confusion between a dermoid cyst and the other two types. The former always presents itself within the mediastinum and the latter usually within the lung parenchyma.