Cytology of Pleural, Pericardial and Peritoneal Cavity Effusions - Effusions - Metastatic Lung Cancer

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Figure 80
Pleural effusion: Adenocarcinoma, lung origin. 20x

Figure 81
Pleural effusion: Adenocarcinoma, lung origin. 20x

Figure 82
Pleural effusion: Adenocarcinoma, lung origin. 60x

Figures 80-82: Pleural effusion: Adenocarcinoma, lung origin.
Photomicrographs show adenocarcinoma.Often it is easy to distinguish adenocarcinoma from mesothelioma. At times sophisticated technology including electron microscopy and immunohistochemistry may assist in defining a likely primary site. Knowing the patient’s history of malignancy is always the key to identifying metastases.

Figure 83
Pleural effusion: Moderately differentiated adenocarcinoma, lung origin. 20x

Figure 84
Pleural effusion: Moderately differentiated adenocarcinoma, lung origin. 60x

Figures 83-84: Pleural effusion, moderately differentiated adenocarcinoma, lung origin.
Note the papillary glandular arrangements of the tumor cells, prominent nucleoli, vacuolization and mitotic figures. Distinctions from other sources of adenocarcinoma may be impossible.

Figure 85
Peritoneal effusion: Adenocarcinoma, lung origin. 20x

Figure 86
Peritoneal effusion: Adenocarcinoma, lung origin. 60x

Figure 87
Peritoneal effusion: Adenocarcinoma, lung origin. 60x

Figures 85-87: Peritoneal effusion: Adenocarcinoma, lung origin.
Clusters of cells with classic features of adenocarcinoma. These cells were ultimately determined to be derived from a bronchogenic carcinoma.

Small cell undifferentiated carcinoma is an uncommon cause of a malignant pleural effusion. The tumor cells are small and dark, and need to be differentiated from lymphoid cells. Features of small cell undifferentiated carcinoma include nuclear molding and individual cell necrosis. Immunohistochemical stains on cell block material may be necessary to confirm the diagnosis.

Figure 88
Pleural effusion: Small cell undifferentiated carcinoma, lung origin. Note small clusters of benign mesothelial cells and three larger cells from small cell undifferentiated carcinoma on the edge of one of the clusters. 60x

Figure 89
Pleural effusion: Small cell undifferentiated carcinoma, lung origin. Nuclei have small nucleoli and often a salt and pepper look to the chromatin. Cytoplasm is scant. 60x

Figure 90
Pleural effusion: Small cell undifferentiated carcinoma, lung origin. Cells of small cell undifferentiated carcinoma are discohesive and can appear singly. Note necrotic background. 60x

Figure 91
Pleural effusion: Small cell undifferentiated carcinoma, lung origin. 20x

Figure 92
Pleural effusion: Small cell undifferentiated carcinoma, lung origin. 40x