Figure 6-34.

Neoplastic effusion. Mesothelioma. Pleural. Cat.

Same case A and B. A, Large cell clusters with papillary formation comprise the majority of the nucleated cell population. (Modified-Wright; IP.) B, Malignant features include anisokaryosis, multinucleation, high and variable nuclear to cytoplasmic ratio, coarse chromatin, and prominent nucleoli. (Modified-Wright; HP oil.) Diagnosis confirmed by immunochemical expression of cytokeratin, vimentin, and calretin.

(Material courtesy of Cheryl Swenson et al., Michigan State University; Case 3 of 2005 ASVCP case review session.)