Congenital pulmonary agenesis.

B-Excessive formations in the development of the lungs. 1-Azygos lobe 2-Supernumerary lobes a-Tracheal lobe b-The so-called lower accessory lobe c-Ectopic lung. The rarity of agenesis of the lung is attested to by the infrequency with which it has been reported in the literature. As of January 1, 1954, there were less than 150 cases reported in medical journals. In a review of 100 cases (96 from the literature and four reported in this paper) there were 40 males and 38 females. In 22 the sex is not mentioned. The right lung was involved in 48 and the left in 52. The age distribution in 86, in which it was mentioned, was as follows: premature, seven; birth to one week, six; one week to one month, eight; one month to three months, three; three months to six months, nine; six months to one year, six; one year to two years, 10; two to five years, eight; five to 15 years, six; 15 to 25 years, eight; 25 to 35 years, three; 35 to 50 years, six; 50 to 65 years, four, and 65 to 72 years, two. Symptoms in patients. with congenital pulmonary agenesis are variable, from complete absence to those of marked cardiorespiratory embarrassment. When symptoms do occur, they are not necessarily due entirely to the agenesis, but may also be due to associated malformations and complications. The most frequent symptoms encountered in patients with