Ovarian choriocarcinoma in a rhesus monkey associated with elevated serum chorionic gonadotropin levels

A clinically normal, 3-year-old female rhesus monkey (Macaca mulatta), which was part of a routine toxicology study, had a mass in the right ovary with metastases to the adjacent mesentery and lungs. The histologic features and immunohistochemistry results were consistent with the diagnosis of choriocarcinoma. Neoplastic cell types included cytotrophoblast (positive for cytokeratin), syncytiotrophoblast (positive for human chorionic gonadotropin), and extravillous trophoblast (positive for human placental lactogen). Because the neoplasm was present in the ovary, the uterus was normal, and the animal was not currently pregnant, this was considered a primary ovarian neoplasm of germ cell origin. The monkey had elevated serum levels of chorionic gonadotropin at the beginning of the study, indicating that, as in women, choriocarcinomas in monkeys can be associated with increased gonadotropin levels and that the tumor was preexisting at the start of the toxicology study.     

Salmonella osteomyelitis in a rhesus monkey

An adult male rhesus monkey (Macaca mulatta) developed clinical signs of severe osteomyelitis of the left femur 42 days after onset of enteritis. Salmonella sp. were cultured from feces, blood, and femoral lesions. Response to antibiotic therapy was poor, and the animal was euthanized. The left femur, with pathologic fracture and involucrum, and the right femur, tibia and fibula were most severely affected. Additionally hepatic microgranulomas, mild tubulointerstitial nephritis, medullary histiocytosis and erythrophagocytosis in the lymph nodes, and a mild colitis were diagnosed microscopically. The severity of the disease and serum electrophoresis findings were suggestive of lowered resistance to the organism, possibly due to anemia or polychlorinated biphenyl toxicosis.     

Campylobacter-induced fetal death in a rhesus monkey

A pregnant 4-year-old rhesus monkey (Macaca mulatta) was presented with a history of acute vaginal bleeding. Physical examination revealed an open cervix. An ultrasound scan demonstrated a viable early third-trimester fetus, approximately 16 weeks of gestational age. Hematology results showed that the monkey was anemic, with a normal leukogram and D?hle bodies. A subsequent cervical culture was positive for Campylobacter fetus. The fetus died 3 days later, and a necropsy of the fetus and placenta was performed. Microscopic examination of the placenta revealed villitis, perivillitis, and deciduitis with S-shaped and gull wing-shaped bacteria. C. fetus was considered the cause of the placental lesions and fetal death; however, the pathogenesis of the infection (hematogenous vs. ascending from the maternal genital tract) was not clear. This is the first report of a Campylobacter-induced fetal death in the rhesus monkey. Because macaques can be asymptomatic carriers and Campylobacter-induced diarrhea is common, this finding has implications for breeding success in nonhuman primate breeding colonies.