[Polyalveolosis: pathogenesis of congenital lobar emphysema?]

Congenital lobar emphysema is an unusual condition and its pathogenesis remains unknown. The variety of findings in pathology studies of the resected specimens led to increasing academic interest. About 50 per cent of the cases have no definitive diagnosis in pathology. The most recent theory proposes an increased number of alveoli within each acinus (polyalveolar lobe).

The aim of this paper is to report the morphometric measures of surgical specimens of 12 patients with congenital lobar emphysema, using the Emery and Mithal technique (radial alveolar count).

We made a case-control study, classifying the cases by age. Mann-Whitney's U test and linear regression techniques were used in data analysis: Mann-Whitney's U in comparing the cases and respective controls and linear regression to evaluate the influence of age in the measures found.

The results revealed a significantly higher radial alveolar count than expected for the age group under 3 years; no difference was observed in the age group between 3 and 7 years and in children older than 7, the radial alveolar count was lower than expected. The normal development of the lung consists in an increasing number of alveoli increase from birth until adulthood, but this number remains constant, independent of age in congenital lobar emphysema.

Such findings allow us to conclude that polyalveolar lobe can and must be diagnosed by a simple and practical method, such as the radial alveolar count, which decreases the incidence of the unknown etiology. The findings of an increased number of alveoli on patients younger than 3 is related to congenital lobar emphysema, since the number of alveoli does not increase in congenital lobar emphysema, just the opposite to what one would expect in the normal development of the lung.