Cytologic Analysis of Malignant Effusion

Eighty cases of malignant effusion were cytologically studied to elucidate the incidence of primary tumor site and cytologic characteristics of each tumor types. Eighty fluid specimens were composed of 43 ascitic, 35 pleural, and 2 pericardial effusion and primary tumor site had been confirmed by histology. The frequent primary sites were stomach(22 cases, 28%), lung(21 cases, 26%), ovary(11 cases, 14%), liver(7 cases, 9%), and breast (4 cases, 5%). The principal malignant tumors were adenocarcinoma (56 cases, 70%), squamous cell carcinoma (7 cases, 9%), liver cell carcinoma (7 cases, 9%), small cell carcinoma (4 cases, 5%), and non-Hodgkin's lymphoma (4 cases, 5%). The distinctive cytologic findings according to primary tumor types were as follows; the gastric adenocarcinomas were mainly characterized by isolated cells and irregular clusters sometimes with signet ring cells. Papillary serous cystadenocarcinoma of ovary showed frequently papillary clusters and occasional psammoma bodies. Breast carcinoma of ductal type showed cell balls with smooth margins. Colonic adenocarcinoma showed rather irregular clusters or palisading pattern of cylindrical cells. Metastatic squamous cell carcinoma, liver cell carcinoma, small cell carcinoma, and non-Hodgkln's lymphoma showed also characteristic features. These findings Indicate that the cytological features observed in the great majority of malignant effusion are similar to those of primary tumor types, which are very helpful to indentify the primary tumor site.