Figure 6-26.

Neoplastic effusion. Lymphoma. Pleural. A, Dog.

Note the individual large round cells with high nuclear-to-cytoplasmic ratio and mildly vacuolated cytoplasm. Also evident are two small lymphocytes and one neutrophil. Light-purple, round structures are free nuclei from lysed cells. These cells cannot be evaluated. The cellularity of this sample is 15,000 cells/μL with a protein of 3.4 g/dL. (Romanowsky.) B, Dog. Note individual lymphoblasts, one mitotic figure, two intermediate-size lymphocytes, and one small lymphocyte. A few lysed cells and red blood cells are also present. (Romanowsky.) C, Cat. Note the monomorphic population of large lymphoblasts, few neutrophils, and few lysed cells. The lymphoblasts are larger than neutrophils and contain a small rim of cytoplasm with a large, round nucleus. The nuclear chromatin is fine and nucleoli are visible in many of the cells. The nucleated cell count of this fluid is 14,000 cells/μL with increased protein (4.0 g/dL). (Romanowsky; × 200.)