Restoration by vacuum inflation of original alveolar dimensions in small human lung specimens

Resection of lung specimens results in deflated and distorted lung structures. If no major airway is present (as in the case of small lung specimens from biopsies), lung dimensions cannot be restored by inflation under 25 cmH2O. This impedes morphological analysis of the tissue. This report describes a simple and easy procedure to restore alveolar dimensions in deflated small lung specimens. Small human lung samples were inflated using moderate vacuum conditions which are provided by a common water stream‐driven vacuum device. Restoration of alveolar dimensions and morphology was evaluated for paraffin‐embedded as well as frozen tissue, using morphometric and immunohistological analysis. Vacuum inflation results in restoration of original lung dimensions as judged by light and scanning electron microscopy, and by analysis of the mean linear intercept, and the average length, width, perimeter and surface area. It also results in markedly improved cutting characteristics, allowing reliable sectioning of 2 µm cryosections and achieving high resolution images in immunofluorescence. Vacuum inflation is a simple and easy procedure to restore lung architecture of small human lung specimens/biopsies with a concomitant improvement of cutting characteristics. It allows for correct histological analysis of small specimens which cannot be inflated otherwise.