Updates in grading and invasion assessment in lung adenocarcinoma

The pathologic evaluation of lung adenocarcinoma, because of greater understanding of disease progression and prognosis, has become more complex. It is clear that histologic growth patterns reflect indolent and aggressive disease, resulting in clearer morphologic groups that can be the underpinning of a grading system. In addition, the progression of adenocarcinoma from a tumor that preserves alveolar architecture to one that remodels and effaces lung structure has led to criteria that reflect invasive rather than in-situ growth. While some of these are based on tumor cell growth pattern, aspects of this remodeling from desmoplasia to artifacts of lung collapse and sectioning, can lead to difficult to interpret patterns with lower reproducibility between observers. Such scenarios are examined to provide updates on new histologic concepts and to highlight ongoing problem areas.

Automated summary

Pathologic evaluation of lung adenocarcinoma has become more complex due to a better understanding of disease progression and prognosis. Different histologic growth patterns reflect varying degrees of aggressiveness in the disease, leading to the need for clearer morphologic groups for grading. The progression of adenocarcinoma from preserving alveolar architecture to remodeling lung structure has introduced criteria for invasive growth rather than in-situ growth.