Fig. 7
From: Solitary tracheal B-cell lymphoma in an adult alpaca (Vicugna pacos)
Histological and immunohistochemical analysis of the tracheal masses. a and d) Both the intraluminal a and extraluminal d masses consisted of sheets of neoplastic lymphocytes growing on a scant fibrovascular stroma. Hematoxylin and eosin (H&E), bar 50 μm. (inset A) The neoplastic lymphocytes displayed a small amount of eosinophilic, homogeneous cytoplasm, and a round nucleus with finely stippled chromatin. b and e The neoplastic lymphocytes observed in the intraluminal b and extraluminal e masses displayed a strong CD20 membranous signal. CD20 immunohistochemical staining, bar 50 μm. c and f Occasional CD3 positive lymphocytes, which most likely represent reactive non neoplastic cells, could be observed among the neoplastic lymphocytes in both the intraluminal c and extraluminal f masses. CD3 immunohistochemical staining, bar 50 μm