Samples of a 3-year-old crossbred sow uterus were submitted, wich presented multiple cysts of variable diameter (0.5 to 5 cm) and serous content adhered to the serous membrane of the organ.
Microscopically, cystic dilatations were observed, originating in the serosa of the uterus and lined by a simple flat epithelium. In the subepithelial lamina, mature connective tissue was observed and, at the point of attachment to the uterus, presence of smooth muscle tissue.

This lesions are known as serous inclusion cysts. The cysts originate from mesothelial cells that become entrapped in the serosa during a rapid involution of the uterus during the postpartum period. It is an incidental finding, they do not have pathological significance or affect fertility but may be related to hormonal dysfunction.

Multiple cysts of varying size and transparent liquid content attached to the uterine serosa.

Image of the other side of the viscera.

Detail of the cysts.