The Management of Pleural Effusions and Chylothorax in Lymphoma
PLEURAL EFFUSIONS in patients with lymphomas have received little attention in the literature in comparison to those in cancer patients. Because the frequency of cancerous effusions is much grea ter, there may be a tendency to manage all patients in a similar fashion, by relying on the instillation of radioisotopes or chemotherapeutic agents into the pleural space. Our experience indicates special considerations in the diagnosis and therapy of such effusions in the lymphomatous diseases. Particular reference will be made to chylothorax; this is found more often in lymphoma patients and can be particularly troublesome because of the rapidity of its reaccumulation.
In many instances, whether the pleural effusion is due to nodal obstruction or to pleural seeding is not clear. Since the etiology dictates the therapeutic approach, it is important to establish the mechanism of fluid formation. At first thought, one might anticipate that mediastinal adenopathy and pleural effusions would always be associated in lymphoma. In fact, however, few patients with mediastinal adenopathy have pleural effusions and few with pleural fluid have detectable mediastinal nodes.
Table I reviews the lymphoma experience (exclusive of Hodgkin's disease) at the University of Rochester Medical Center in the past ten years. Clinical and radiographic analysis showed the incidence of mediastinal adenopathy to be less than that of pleural fluid, i.e., 26 per cent versus 33 per cent respectively. The biassociation of pleural fluid and nodes was infrequent; 71 per cent (15/21) of the patients with effusions were without overt mediastinal disease on films.
Further analysis of these 15 patients indicates that only 8 are germane to this report because they were symptomatic and successfully treated by mediastinal irradiation. Three patients treated with nitrogen mustard only will be discussed later. The effusions were incidental in the course of 4 other patients: in 2, asymptornatic slight effusions were detected on radiographs, and 2 were in congestive heart failure which cleared with diuretics and digitalis.
(a) Exudates versus Transudates: Malignant pleural effusions are generallyexudates with a serosanguineous appearance. They are rich in protein and commonly reveal a positive cytology. The pleural effusions associated with lymphomas, however, differ from the usual cancerous effusions and present characteristics of both transudates and exudates. The specific gravity of the fluid is a major factor in differential diagnosis and reflects the variation of the protein content. The statement is frequently made that the specific gravity of transudates is below 1.015 and that of exudates is above 1.018 (1).The tabulated data of our patients show it to fall between these values in most cases; in one rare instance it exceeded 1.018.