elastin and Adenocarcinoma--Papillary

Elastin and collagen are the main components of the lung connective tissue network, and together provide the lung with elasticity and tensile strength. In pulmonary pathology, elastin staining is used to variable extents in different countries. These uses include evaluation of the pleura in staging, and the distinction of invasion from collapse of alveoli after surgery (iatrogenic collapse). In the latter, elastin staining is used to highlight distorted but pre-existing alveolar architecture from true invasion. In addition to variable levels of use and experience, the interpretation of elastin staining in some adenocarcinomas leads to interpretative differences between collapsed lepidic patterns and true papillary patterns. This review aims to summarise the existing data on the use of elastin staining in pulmonary pathology, on the basis of literature data and morphological characteristics. The effect of iatrogenic collapse and the interpretation of elastin staining in pulmonary adenocarcinomas is discussed in detail, especially for the distinction between lepidic patterns and papillary carcinoma.

Topics: Adenocarcinoma of Lung; Adenocarcinoma, Papillary; Collagen; Diagnosis, Differential; Elastin; Histocytochemistry; Humans; Lung Neoplasms; Pleura; Pulmonary Alveoli

Surgical removal and pathologic handling of lung tissue has a compressive effect upon its architecture. The effect of surgical atelectasis on morphology has not been examined in depth, especially with respect to lung adenocarcinomas.. To examine the influence of surgical atelectasis on morphologic lepidic growth pattern, mimicking papillary adenocarcinoma pattern.. In 2 cases serial sections of resected pulmonary adenocarcinoma were used, as was a 3-dimensional reconstruction. Elastin stains were performed on primary and metastatic adenocarcinomas.. Perfusion fixation of another case showed marked morphologic differences of less compressed peripheral lung tissue, emphasizing the preexisting alveolar structure. An elastic stain may help identify true lesional architecture.. We demonstrate that microscopic sections of adenocarcinoma in situ in compressed/collapsed tissue may give rise to a pseudopapillary pattern mimicking invasive adenocarcinoma. Accurate appreciation of different tumor architecture in lung adenocarcinoma has important biologic and clinical implications. Pathologists should be aware of the possibility of misclassification of adenocarcinoma pattern due to tissue artifacts caused by lung tissue handling.

Topics: Adenocarcinoma; Adenocarcinoma, Papillary; Aged, 80 and over; Artifacts; Biomarkers, Tumor; Diagnosis, Differential; Elastin; Female; Histocytochemistry; Humans; Lung; Lung Neoplasms; Male; Middle Aged; Specimen Handling; Tomography, X-Ray Computed