Malignant pleural effusions due to adeno-endocrine-cell carcinoma of the appendix: a case report

The cellular features of adeno-endocrine-cell carcinoma of appendiceal origin are presented. The pleural fluid contained metastatic predominantly atypical cells in linear cluster accompanied by numerous mesothelial cells. The cells had small round nuclei, with a slight tendency to molding; nucleoli were absent. The cytologic findings in Papanicolaou-stained smears of the pleural fluid suggested a metastatic small-cell carcinoma of the lung. Subsequently, adeno-endocrine-cell carcinoma of the appendix was demonstrated at autopsy. Reports of such occurrences are few; no study, to the best of our knowledge, has previously documented the cytologic diagnosis in pleural fluid.