Selected Background Findings and Interpretation of Common Lesions in the Female Reproductive System in Macaques

Abstract

The authors describe a selection of normal findings and common naturally occurring lesions in the reproductive system of female macaques, including changes in the ovaries, uterus, cervix, vagina, and mammary glands. Normal features of immature ovaries, uteri, and mammary glands are described. Common non-neoplastic lesions in the ovaries include cortical mineralization, polyovular follicles, cysts, ovarian surface epithelial hyperplasia, and ectopic ovarian tissue. Ovarian neoplasms include granulosa cell tumors, teratomas, and ovarian surface epithelial tumors. Common non-neoplastic uterine findings include loss of features of normal cyclicity, abnormal bleeding, adenomyosis, endometriosis, epithelial plaques, and pregnancy-associated vascular remodeling. Hyperplastic and neoplastic lesions of the uterus include endometrial polyps, leiomyomas, and rarely endometrial hyperplasia and endometrial adenocarcinoma. Vaginitis is common. Cervical lesions include endocervical squamous metaplasia, polyps, and papillomavirus-associated lesions. Lesions in the mammary gland are most often proliferative and range from ductal hyperplasia to invasive carcinoma. Challenges to interpretation include the normal or pathologic absence of menstrual cyclicity and the potential misinterpretation of sporadic lesions, such as epithelial plaques or papillomavirus-associated lesions. Interpretation of normal and pathologic findings is best accomplished with knowledge of the life stage, reproductive history, and hormonal status of the animal.

Evaluating the progenitor cells of ovarian cancer: analysis of current animal models

“…Both humans and non-human primates develop ovarian cancers at low rates, with human females having an approximately 2% risk of developing ovarian carcinomas, and non-human primates having about a 0.4% risk (37)(38)(39). However, unlike in humans, where the vast majority of ovarian cancers are epithelial, the most common types of ovarian cancer in non-human primates are granulosa cell tumors or sex-cord stromal tumors (36,40). Carcinomas account for about 23% of the ovarian cancers detected in non-human primates, and these show remarkable similarity to those observed in humans, as all four histotypes have been observed and show similar patterns of progression and metastasis (36).…”

The Macaque Endometrium, with Special Reference to the Cynomolgus Monkey (Macaca fascicularis)

“…In a separate paper in this monograph, we refer to the background findings in the reproductive organ system and mammary gland of the cynomolgus monkey in more detail (see Cline et al, 2008).…”

Bilateral Ovarian Cysts Originating from Rete Ovarii in an African Green Monkey (<i>Cercopithecus Aethiops</i>)

“…They have been also reported in many animals, including dogs, cats, cattle, horses, pigs and monkeys [1,11,12]. Among monkeys, ovarian cysts in macaques such as rhesus and cynomolgus monkeys have been well documented in previous reports [3,12]. But there are few reports of ovarian cyst in the African green monkey.…”

“…On the other hand, ovarian cyst in the guinea pig as a disease model of PCOS has been reported previously [8]. In cynomolgus monkeys, mesonephric duct cysts are reported to be the most frequent cysts [3], whereas, in rhesus monkeys, cystic rete ovarii are the most common cysts, followed by mesonephric duct cysts and then follicular cysts [12]. But, there is no report describing the incidence of ovarian cyst in African green monkeys.…”