The involvement of serous cavities by malignant neoplasms has
important therapeutic and prognostic implications. The diagnosis of
metastatic cancer in pleural, peritoneal or pericardial fluids is of capital
importance for the patient and the attending physician or surgeon.
In most such instances, the rapid fatal outcome of the disease may
be anticipated. However, with the use of appropriate therapy, some
metastatic tumors offer a much better prognosis than others. For
example, metastatic mammary carcinoma may be controlled, often
for a period of several years, by means of hormonal manipulation or
chemotherapy. Malignant lymphomas and some malignant tumors of
childhood respond to energetic therapeutic measures. Therefore, the
responsibility of the pathologist is to identify cancer cells accurately
and to identify tumor type and if possible, the site of primary
origin. The latter task is greatly facilitated by simultaneous review
of histopathological material, if available and by an accurate clinical
history