Intravascular T-cell lymphoma in a patas monkey (Erythrocebus patas)

Abstract

A 9-year-old female captive patas monkey (Erythrocebus patas) presented with poor general condition, inability to stand, petechiae, anaemia, thrombocytopenia, and leukocytosis. Due to poor response to treatment, the animal was euthanized 16 days later. Postmortem examination revealed hemorrhages in several organs and bilateral cerebral infarctions. Histologically, prominent accumulations of large neoplastic lymphocytes in cerebral and meningeal blood vessels were demonstrated within the lesions and in other organs (e.g., bone marrow, ovary, intestine). Immunohistochemically, neoplastic cells expressed CD3 and Ki-67. PCR revealed a lymphocryptovirus (LCV) infection, while Epstein-Barr nuclear antigen 2 (EBNA2) could not be demonstrated within neoplastic cells by means of immunohistochemistry. Based on the pathological findings, an intravascular lymphoma (IVL) of T-cell origin was diagnosed. To the authors' knowledge, this is the first report on this rare entity in a nonhuman primate.

Figure 1

Infarctions with hemorrhages (white arrows) in both cerebral hemispheres.

Figure 2

Cerebral capillaries distended by intravascular emboli of large pleomorphic neoplastic lymphocytes. Adjacent cerebral parenchyma displays loss of architecture, infiltration with numerous foamy macrophages, lymphocytes, as well as hemosiderin and hematoidin deposition. H & E. Bar: 20 $\mathrm{\mu }$m.

Figure 3

Corresponding emboli of neoplastic lymphocytes distending multiple capillaries within the cerebellum. The adjacent cerebellar parenchyma appears normal. H & E. Bar: 20 $\mathrm{\mu }$m.

Figure 4

Accumulation of large neoplastic lymphocytes filling the lumina of multiple venules and capillaries within the ovary. Neoplastic cells show a strong cytoplasmic CD3 expression. IHC, SABC method. Bar: 20 $\mathrm{\mu }$m.

Figure 5

Venous vessel of a mesenterial lymph node with intravascular neoplastic lymphocytes highlighted by a marked nuclear Ki-67 signal. IHC, SABC method. Bar: 20 $\mathrm{\mu }$m.