Myelomatous pleural effusion: clinical course and immunologic characterization of the pleural fluid cells

Diagnostic value of total and differential leukocyte counts in pleural effusions

Total and differential leukocyte counts in pleural fluid were determined prospectively in 140 consecutive patients undergoing diagnostic thoracentesis. The total number of leukocytes was higher in exudates than in transudates. Lymphocytes predominated overwhelmingly (more than 80% of all leukocytes) in 29 of the 31 effusions with verified or probable tuberculous etiology and in 18 of the 24 with malignant etiology, as well as in 20 exudative pleural effusions of other causes. The significant differences in the percentage of lymphocyte distinguished tuberculous effusions from parapneumonic (p less than 0.001), nonspecific (p less than 0.001) and rheumatoid effusions (p less than 0.005), as well as from effusions caused by undefined connective tissue disease (p less than 0.001). Eosinophilia (more than 10%) of the pleural fluid was not present in any patient with proven tuberculosis and in only one patient with malignant effusion (malignant mesothelioma) but did occur in 12 of the 26 patients with nonspecific effusion. These results show that a great lymphocytic predominance is characteristic particularly of tuberculous but also of malignant pleural effusions, although this predominance cannot be regarded as disease-specific. Eosinophilia of the pleural fluid--usually a nonspecific sign--indicates nontuberculous, nonmalignant etiology.

Cytology and flow cytometry of malignant effusions of multiple myeloma

Identifying malignant plasma cells in body fluids from multiple myeloma patients is important for therapeutic and prognostic considerations. This can be difficult when plasma cells are mature in appearance or low in number. We examined the cytological and flow cytometric findings of myelomatous pleural and pericardial effusions from 8 patients with advanced multiple myeloma. Cytoplasmic immunoglobulin light chain excess vs. DNA ploidy in the plasma-cell population was evaluated by flow cytometry (FCM). The cytology smears of one pericardial and 14 pleural effusions from the 8 patients were reviewed. Screening Papanicolaou-stained smears facilitated the detection of malignant nuclear features; however, morphology of plasma cells was best seen in Diff-Quik-stained smears. Low cellularity and inadequate air-drying of smears accounted for the false-negative cytology seen in two fluids from a single patient. A malignant plasma cell population was identified in 9 of 10 fluids submitted for FCM, including the two fluids with negative cytology. The false-negative FCM was from a suboptimal specimen with high background staining. Six fluids had an aneuploid DNA content, and four were diploid. A combination of Papanicolaou- and Diff-Quik-stained smears is recommended for the evaluation of plasma cells in effusions from patients with multiple myeloma. Cytology and flow cytometry confirmed malignancy in 87% and 90% of fluids evaluated, respectively; all cases were diagnosed by either one or both methods. Our results suggest that FCM and cytology of serous effusions in multiple myeloma patients are complementary and should be used in difficult cases. Diagn. Cytopathol. 2000;22:147-151.

Myeloma

Myeloma is a malignancy of plasma cells that are terminally differentiated B-lymphocytes. The clinical spectrum varies from the incidental discovery of a pathologically raised monoclonal immunoglobulin on routine electrophoresis in asymptomatic patients to widespread skeletal involvement with incapacitating bone pain. Symptoms may result from a solitary tumor mass, described as an extramedullary plasmacytoma, in virtually any part of the body. Metabolic abnormalities commonly include hypercalcemia, elevated plasma urate levels, or the development of amyloidosis, all of which may disturb renal function. High paraprotein levels cause hyperviscosity, resulting in generalized debility and varying degrees of disturbed mental function. The natural history is determined by the mass of the tumor coupled with its unique biologic features. Median survival of unselected patients, without effective treatment but once symptoms are evident, is approximately 7 months; this period can be significantly prolonged with appropriate therapy. As a first step, urgent medical management is often necessary, centering on rehydration, correction of hyperviscosity, and reversal of metabolic defects, each of which may improve renal function. Over the longer term, specific antitumor drugs have extended median survival to approximately 30 months, and most regimens include a combination of melphalan and prednisone, with or without other cytotoxic drugs. Alternative forms of treatment include sequential hemibody irradiation, recombinant alpha interferon, and in suitably selected patients, high-dose chemoradiotherapy followed by bone marrow transplantation. The latter approaches offer promising management options and are currently the subject of evaluation in controlled clinical trials.

Light chain myeloma with meningeal and pleural involvement

A 76-year-old woman with newly diagnosed lambda light chain myeloma was found to have involvement of the pleura and meninges. Direct immunofluorescence demonstrated the monoclonal nature of plasma cells found in the pleural fluid; morphologically similar cells were found in the cerebrospinal fluid and bone marrow. Immunoelectrophoresis revealed lambda light chains in the pleural fluid and cerebrospinal fluid, as well as in the serum and urine. Clinically apparent pleural involvement and meningeal involvement by myeloma are each rare events. This is believed to be the first report of both phenomena occurring simultaneously and the first known case of light chain myeloma involving the cerebrospinal fluid.