Cytology of B Cell Lymphomas in Cattle Infected with Bovine Leukosis Virus

Abstract

Lymphoid neoplasms in 17 cattle having tested positive for bovine leukosis virus (BLV) were investigated by histology and immunohistochemistry. In 16 cases, the neoplastic cells were characterized by a marked variation in cell size, atypia in large cells, nuclear irregularity in smaller cells, and nucleolar prominence in cells with scant cytoplasm. These cytological features were used to specifically define pleomorphic lymphomas. In addition to lymphoid cells, immunoblastoid and plasmacytoid cells containing cytoplasmic immunoglobulin G were observed in the remaining case. Since a similar case was recorded as lymphoplasmacytoid lymphoma in a BLV-negative cow, this polymorphic case may not be related to the virus. Most lymphoma cases associated with BLV are classified as pleomorphic, and neoplasms termed enzootic leukosis should be diagnosed based on tumor cell morphology.

Nucleolar Organizer Region Count, PCNA and Ki-67 Indices are Diagnostic Markers of Malignancy and Cell Proliferation Rate in Bovine Lymphosarcoma

“…Mitotic figures were present. Iwama et al [21] and Branco et al [22] observed similar histological features.…”

“…Grossly, the enlargement was noticed in prescapular and precrural lymph nodes in calves and there was enlargement and fusion of mesenteric lymph nodes in the cow. The affected organs were soft, fleshy, greyish white and on cut section, the lymph nodes showed bulging and a homogenous pale appearance with no demarcation between cortex and medulla [14,15,[19][20][21]. Impression smears collected from affected lymph nodes and organs like heart, lung, liver and kidney revealed numerous cells which included lymphocytes, prolymphocytes and lymphoblasts.…”

Mantle Cell Lymphoma with Histological Progression to Pleomorphic Lymphoma in Two Cattle

“…Large and pleomorphic cells including cells with prominent nucleoli are observed in the pleomorphic variant of human mantle cell lymphoma (Swerdlow et al 2008). In contrast, the current cases showed histological transition from neoplastic mantle cells to larger and more pleomorphic cells, and the latter morphologically corresponded to pleomorphic B cell lymphoma cells (Murayama et al 2011, Iwama et al 2013, Hagiwara et al 2014. Lymph nodes composed chiefly of neoplastic pleomorphic cells showed a tendency toward severe enlargement in case 1, and thus were considered to be in the later stages of tumor development.…”

“…The absence of cIg in human and bovine mantle cell lymphomas can be explained by the fact that mantle cells correspond to naive pre-germinal center B cells (Feller & Diebold 2004). Pleomorphic B cell lymphoma is characterized by a lack of staining for cIg in cattle (Iwama et al 2013); therefore, we suggest that neoplastic mantle cells in the present cases have transformed into more atypical and pleomorphic cells, but have not differentiated into more mature cells such as cIg-producing immunoblasts (Murayama et al 2011).…”

“…In cattle, most lymphomas associated with bovine leukemia virus (BLV) are characterized by cytological pleomorphism and atypia, and are designated pleomorphic B cell lymphomas (Kagawa et al 2009, Murayama et al 2011, Iwama et al 2013, Hagiwara et al 2014. Some cases are macroscopically characterized by abdominal tumor masses and considered to be derived from B-1 cells in the abdominal cavity (Abe et al 2007, Hagiwara et al 2014.…”