The tuberculous round focus in its chronic form.

Since 1947, with the beginning of the immigration to Israel on a large scale, systematic x-ray examinations were done on immigrants in the reception camps. Now our mass radiographic studies include 350,000 people. In the first years, 1947-48, the high percentage of cases with active tuberculosis of the lungs was striking (0.8 per cent), and among them we found one particular form of tuberculous lesion of the lung: the tuberculous round focus in its chronic form, a lesion which does not become apparent on clinical examination. It Is the purpose of this paper to deal with it. Those examined were new immigrants to Israel, the majority of whom came at that time from concentration camps in Germany. The minographic films showed small, dense, well defined rounded shadows situated predominantly in the upper lung fields. Their density and their well defined character made them suggestive of fibrotic lesions. But clinical, radiological, and especially bacteriological examinations, carried out over a considerable time, brought us to the conclusion that we were deallng with a chronic round focus, which in the majority of our cases turned out to be the manifestation of an active tuberculous process of latent character. During 1947-48, 104 cases of round foci of this type were seen on minographic examination of whom 53 were males and 51 were females. More than 50 per cent (59 cases) were 20 to 30 years of age, the usual age groups mostly affected by t’uberculous infection. Of those 104 cases of round foci 85 were single, while 11 showed two foci. One case only showed more than four foci. The total number of round foci recorded was 136 of which 78 were in the right lung and 58 in the left. The most frequent localization was in the upper lung fields, particularly in the second anterior intercostal space, where 72 occurred (31 in the first intercostal space and 13 In the third). The lower lobes were the site of the lesions in 14 cases, of which six were In the apical segments. One hundred and fourteen (83 per cent) of the lesions showed a typical rounded form, 14 were oval and eight were angular in appearance. The lesions were relatively small. Sixty-two were 1 to 2 cm. in diameter, 52 were 1 cm., and 22 were larger than 2 cm. In 11 cases deposits of calcium were noted within the foci. In reading the films a close search was made for additional changes within the lung fields which is important with regard to the pathogenesis of the round foci. In 75 per cent no additional tuberculous changes were found, either in the vicinity of the round foci, or in other lung fields. In nine cases struc-