Morphological artifacts in pulmonary pathology and literature review

In pathology practice, understanding pre-analytical and analytical variables is fundamental for an accurate interpretation of the microscopic morphology of each organ. The lung is susceptible to several artifacts, which can alter the final microscopic appearance of the specimen, including (i) morphological changes ex vivo compared to the in vivo state, (ii) effects of presurgical and surgical procedures, and (iii) pre-analytical and analytical variables. In this article, the main iatrogenic artifacts described in pulmonary pathology are summarized, as well as the effects of previous biopsies, positive pressure ventilation, surgical collapse, clamping edema, consequences of surgical resection, intravascular procedures (hydrophilic polymer embolism and lipoid pneumonia due to lipid emulsions), and consequences of pathology handling. Specific artifacts are also highlighted in detail, including hook wire placement, clamping edema, cell and tissue handling, fixation delay, iatrogenic collapse, freezing of lung parenchyma, and tissue displacement. Awareness of these artifacts is crucial for proper interpretation and accurate histologic diagnosis of lung specimens.