The tumor-node-metastasis (TNM) staging system for lung cancer has been modified since its first edition in the late 1960s. Its seventh edition has been recently published and, for the first time, a truly worldwide database was analyzed in order to propose modifications in the staging. Significant changes have been made in the tumor and metastasis descriptors. Although the recommendations for the node descriptor have remained unchanged, the analysis of the factors related to this descriptor suggests that modifications will be made in the future. The forthcoming revisions of the TNM staging system might take the molecular aspects of lung cancer into consideration, aiming at a more refined staging system.

Keywords: Lung neoplasms; Neoplasm staging; Epidemiologic methods.

Thymolipoma is a very rare benign neoplasm of the thymus. We present the case of a 42-year-old male with a massive mediastinal tumor discovered on a chest X-ray after a motorcycle accident. The patient had no complaints, and his physical examination was unremarkable. Chest CT scans revealed a lipomatous mass containing areas of soft tissue density. The patient was submitted to median sternotomy expanded to left anterolateral thoracotomy, resulting in the complete excision of the tumor. The pathological diagnosis was thymolipoma. Thymolipoma usually attains enormous dimensions by the time of diagnosis, and the occasional symptoms are related to compression of adjacent structures. Surgical resection is the treatment of choice and offers the only possibility of cure. The airway deserves special care during anesthesia induction.

Keywords: Thymus neoplasms; Mediastinal neoplasms; Thymectomy; Lipoma.

Objective: To investigate the effects of maternal protein malnutrition during lactation on the elastic fibers in the tracheas of Wistar rat pups. Methods: At delivery, 12 male pups of two Wistar rat dams were equally divided into two groups: control, in which the dam received water and standard rat chow ad libitum during lactation; and protein-restricted (PR), in which the dam received water ad libitum and an isoenergetic PR diet (8% protein). At 21 days of age, the pups were killed and their tracheas were excised. The elastic fibers were stained with Weigert's resorcin-fuchsin (after oxidation) and evaluated under light microscopy. Morphometric determinations were performed by stereology, with the point-counting method, and expressed as volumetric densities. Results: Elastic fibers, most having a longitudinal distribution, were identified beneath the tracheal mucosa. In addition, well-defined circular layers of elastic fibers were found around the inner and outer surfaces of the cartilaginous ring. There were no differences between the groups regarding the organization and distribution of the elastic fibers. The volumetric density of the elastic fibers of the pups in the control and PR groups was 2.46 ± 0.99% and 3.25 ± 1.13%, respectively (p < 0.01). Conclusions: The volumetric density of elastic fibers appears to be greater in rat pups breastfed by dams receiving a PR diet than in those breastfed by dams receiving a normal diet.

Keywords: Trachea/growth and development; Trachea/anatomy and histology; Extracellular matrix; Airway remodeling; Malnutrition.