Spontaneous neoplasms observed in cynomolgus monkeys (Macaca fascicularis) during a 15-year period

A total of 33 tumors were observed during a time period of 15 years (1992–2006) in cynomolgus monkeys. The great majority of neoplasms was benign (23 benign neoplasms versus 10 malignant tumors). Fourteen appeared in males and 19 in females. The age of tumor-bearing animals ranged between 2 years 2 months and 13 years 9 months. Most of the tumors (22) in the cynomolgus monkeys were seen in endocrine organs (adrenal cortical adenoma, adrenal hemangioma, C-cell carcinoma, follicular adenoma), respiratory system (nasal cavity adenoma, pulmonary squamous cell carcinoma, bronchio-alveolar carcinoma, bronchiolar papilloma, chondromatous hamartoma) and female genital system (uterine polyp, uterine adenoma, uterine leiomyoma and teratoma of the ovary). Four animals revealed malignant lymphoma infiltrating multiple organs.