Ovarian pathology in rhesus macaques: a 12-year retrospective

BACKGROUND

Ovarian pathology is an important cause of decreased fertility and reproductive capability and may impact multiple systems, particularly in aging rhesus macaques.

METHODS

Retrospective histopathologic and immunohistochemical analysis of 458 female rhesus macaque necropsies over 12 years at the New England Primate Research Center in Southborough, MA.

RESULTS

Degenerative and inflammatory changes in the ovaries included mineralization, infiltration by lymphocytes, macrophages and multinucleated giant cells, endometriosis, and arteriopathy. Cystic changes included follicular cysts, cystic rete, and mesonephric duct cysts with cystic rete the most common. Neoplasms included granulosa cell tumors, cystadenoma, cystadenocarcinoma, and teratoma.

CONCLUSIONS

Ovarian lesions of the rhesus macaque are similar to those of cynomolgus macaques and humans. These lesions are frequently incidental findings but may impact metabolic and neurocognitive studies.

Rhesus lymphocryptovirus type 1-associated B-cell nasal lymphoma in SIV-infected rhesus macaques

Epstein-Barr virus (EBV) is a worldwide endemic gamma herpesvirus of the genus Lymphocryptovirus (LCV) that infects more than 90% of the world's population. EBV has been associated with a variety of malignancies, but it has a demonstrated role in lymphomas, especially in immunosuppressed individuals. Lymphomas of the nasal cavity, paranasal sinuses, and nasopharynx are uncommon and constitute less than 5% of all extranodal lymphomas. Sinonasal non-Hodgkin's lymphomas have been reported in patients infected with human immunodeficiency virus (HIV) at an increased frequency. Rhesus LCV (rhLCV), the rhesus viral homolog of EBV, has been cloned and is associated with B-cell lymphomas in immunosuppressed rhesus macaques. We report two cases of B-cell lymphoma within the nasal cavity from 2 simian immunodeficiency virus-infected rhesus macaques with acquired immunodeficiency syndrome. The B-cell phenotype and rhLCV association were demonstrated by immunohistochemistry and confocal microscopy. The majority of the nuclei of the neoplastic B lymphocytes were EBNA-2 positive. RhLCV type 1 sequences were verified from the neoplasms by polymerase chain reaction. Nasal lymphoma is an unusual presentation of rhLCV-associated B-cell lymphoma in immunosuppressed rhesus macaques. These tumors demonstrate comparable viral pathogenesis with EBV-induced nasal lymphomas in HIV-positive people.