Ovarian remnant syndrome: revascularization of free-floating ovarian tissue in the feline abdominal cavity

Nine, healthy, intact female domestic shorthair cats were ovariohysterectomized. At the time of surgery and following removal, the major portion of one ovary was loosely sutured to the mesentery and replaced in the abdominal cavity. Six months later, an abdominal laparotomy was performed in order to retrieve the ovarian remnants. Histopathological examination of the remnants showed viable tissue and evidence of ovarian follicles or corpora lutea in eight of nine (88.9%) cats. The ninth ovarian remnant was atrophied and fibrotic. Measurement of serum estradiol and progesterone, vaginal cytology, and stimulation of estrus and ovulation with a protocol using pregnant mare serum gonadotropin (PMSG) followed by human chorionic gonadotropin (hCG) were unreliable indicators of ovarian activity in this study. Revitalization of an ovarian remnant was shown to occur in the absence of surgical implantation.