Answer
Lung transplantation–related pathology encompasses a spectrum of disorders that include, but are not limited to, indications for lung transplantation (seen in explanted lungs), surgical complications (airway anastomotic and vascular complications), ischemia-reperfusion injury, rejection (acute and chronic), infections, and posttransplantation lymphoproliferative disorders (PTLDs).
Over the last few decades, lung transplantation has become an accepted modality of treatment for many end-stage lung diseases. With greater experience and analysis of significant numbers of cases, lung transplant recipients are living longer, and follow-up regimens are becoming streamlined. Thus, a comprehensive understanding of lung transplantation–related pathology is necessary for both tertiary care pathologists dealing with highly specialized lung transplantation teams and a much larger spectrum of healthcare providers who may be involved in the care of lung transplant recipients or candidates for lung transplantation.
Clinical features of lung transplantation–related pathology can range from an absence of symptoms to signs and symptoms of respiratory distress and/or infection and are not detailed in this article. Of note, clinical findings do not play a role in the pathologic grading of rejection.
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Lung transplantation-related pathology. Intraalveolar multinucleated giant cell indicates microaspiration in this posttransplant transbronchial biopsy specimen (hematoxylin and eosin [H&E], 200x)
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Lung transplantation-related pathology. This image depicts minimal acute cellular rejection with incomplete perivascular cuff of inflammatory cells (grade A1) (hematoxylin and eosin [H&E], 200x).
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Lung transplantation-related pathology. This image shows mild acute perivascular rejection with a thick complete cuff around a blood vessel (grade A2) (hematoxylin and eosin [H&E], 200x).
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Lung transplantation-related pathology. Moderate acute perivascular rejection is revealed: The inflammation extends into adjacent alveolar walls and is accompanied by fibrinous exudates (grade A3) (hematoxylin and eosin [H&E], 200x).
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Lung transplantation-related pathology. Note the minimal acute airway rejection shown: There is focal inflammation in the submucosa (grade B1) (hematoxylin and eosin [H&E], 200x).
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Lung transplantation-related pathology. This image demonstrates mild acute airway rejection: There is a bandlike infiltrate in the submucosa (grade B2) (hematoxylin and eosin [H&E], 200x).
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Lung transplantation-related pathology. Moderate acute airway rejection is revealed: The inflammatory infiltrate extends into the overlying epithelium (grade B3) (hematoxylin and eosin [H&E], 200x).
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Lung transplantation-related pathology. This image shows bronchial-associated lymphoid tissue (BALT): A collection of small mature lymphocytes is present which is associated with pigment. Although no airway is seen in this figure, the morphologic appearance is not that of rejection (hematoxylin and eosin [H&E], 100x).
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Lung transplantation-related pathology. Bronchiolitis obliterans (chronic rejection) is revealed: The patient underwent retransplantation for chronic rejection, which is seen here as eccentric fibrosis partially occluding the airway lumen. Note the presence of scant inflammatory cells and plump fibroblasts in the lesion (hematoxylin and eosin [H&E], 100x).
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Lung transplantation-related pathology. This image demonstrates bacterial infection: The presence of mostly neutrophils in both the submucosa and mucosa is most suggestive of an infection (hematoxylin and eosin [H&E], 200x).
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Lung transplantation-related pathology. The image reveals cytomegalovirus (CMV) infection by immunohistochemical (IHC) staining: Both enlarged nuclei and normal-sized infected nuclei stain positively. This feature is helpful when viral inclusions are not readily apparent on hematoxylin and eosin (H&E) stain. (IHC stain using antibody against immediate early antigen, 200x)
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Lung transplantation-related pathology. This image demonstrates posttransplant lymphoproliferative disorder (PTLD): There is a diffuse infiltrate of atypical lymphoid cells, obliterating the lung architecture, with a foci of necrosis, as would be seen in a large-cell lymphoma (hematoxylin and eosin [H&E], 200x).
