Figure 2

Hematoxylin and eosin stain of proximal esophagus from a 24-year old male California sea lion ( Zalophus californianus ) with lymphoblastic lymphoma. Multicentric lymphoblastic lymphoma involving the esophagus was diagnosed in a geriatric sea lion by routine histopathology. Similar findings were identified in the adrenal gland, urinary bladder, colon, heart, kidneys, liver, lymph nodes, pancreas, spleen, stomach, tonsil, thyroid, trachea, tongue, and ureter. Aggregates of neoplastic cells were scattered within affected tissues and often clustered at mucosal and submucosal junctions or within mucosal epithelium. A. Clusters of neoplastic cells (arrow) are present in the mucosa, submucosa, and in submucosal blood vessels. B. High power (400X) magnification of the moderate to large neoplastic round cells with large round to indented nuclei and coarsely stippled chromatin