Endometriosis in a rhesus monkey

Abstract

Spontaneous endometriosis was found in a 15-year-old female rhesus monkey. Macroscopically, there was thickening of the intestinal wall, mesenterium, and the gastrocolic omentum. Sporadic nodules were noted in the serosa of the jejunum and ileum. Histopathologically, a large number of glandular tubules along with massive connective tissue was observed in the serosa and subserosa. The glandular tubules were covered with mono- or multilayered epithelial cells with ciliary structures protruding into the glandular lumen. The connective tissue was composed of mesh-like fiber, fibroblast-like cells, and tortuous blood vessels. The glandular tubules and the connective tissue were similar to the glands and interstitial tissue in the endometrium.