Reactive Mesothelial Cells In Pleural Fluid Cytology

Normally mesotheial cells present only along surface and not in underlying tissue.

Reactive mesothelial cells in pleural fluid cytology.

Papanicolaou x100 breast adenocarcinoma cells in pleural effusion. Hyperplastic mesothelial cells with slightly enlarged nuclei micronucleoli and a clear space or window between adjacent cells present singly and in small clusters. Reactive pleural effusion showing acute and chronic cells normal mesothelial cells and alveolar macrophages in aggregates and dispersed cells with rounded nuclei and vacuolated cytoplasm. Because of the difficulty in distinguishing reactive mh from mm even in tissue specimens such as small pleural biopsies several studies have used immunohistochemical markers to distinguish between reactive and neoplastic mesothelial cells 3 8 or between adenocarcinoma reactive mh and mm in serous effusions.

The many faces of reactive mesothelial cells. An introduction to cytopathology is in the cytopathology article. The mesothelial cells have central round nuclei with a moderate amount of light purple cytoplasm and a corona or fringe to the cytoplasmic borders. Many of the false positives in effusion fluid cytology are caused by the atypical features of reactive mesothelial cells associated with a variety of underlying benign processes including acute pancreatitis 2 tuberculosis 1 ovarian fibroma 1 pulmonary infarction 3 chemotherapy 4 and cirrhosis.

9 14 these studies suggest that 2. Larger clusters of hyperplastic mesothelial cells showing mildly nuclear atypia with small nucleoli. Atypical mesothelial cell proliferation. Epithelial or lining cells most commonly mesothelial cells 1 the appearance and presentation of nucleated cells found in pleural fluid and whether they are considered common benign or abnormal is discussed below.

The article deals with cytopathology specimens from spaces lined with mesothelium i e. Bap1 a new marker that is helpful in distinguishing reactive mesothelial cells from malignant mesothelioma. Neoplastic transformation of mesothelial cells results in malignant mesothelioma an aggressive tumor especially the pleura. The distinction between reactive and malignant mesothelial cells has long been a challenge in effusion cytology.

Mesothelial cells form conspicuous layer of regularly spaced bland cuboidal cells along pleural surface. Numerous mesothelial cells are seen in this pleural fluid from a dog with a transudative effusion with concurrent diapedesis of red blood cells or hemorrhage. It deals with pericardial fluid peritoneal fluid and pleural fluid.