In our previous report, we have noted an increase of computed tomography (CT) attenuation values in perirectal fat tissue after Gant-Miwa-Thiersch (GMT) procedure for rectal prolapse. Based on these results, we hypothesized that the GMT procedure may have a rectal fixation effect due to inflammatory adhesions extending to the mesorectum. Herein, we report a case of laparoscopic observation of perirectal inflammation after GMT. A 79-year-old woman with a history of seizures, stroke, subarachnoid hemorrhage, and spondylosis underwent the GMT procedure under general anesthesia in the lithotomy position for rectal prolapse measuring 10 cm in length. But rectal prolapse recurred 3 weeks after surgery. Therefore, an additional Thiersch procedure was performed. However, rectal prolapse still recurred, and laparoscopic suture rectopexy was performed 17 weeks after initial surgery. During rectal mobilization, marked edema and rough membranous adhesions were observed in the retrorectal space. The average CT attenuation value obtained 13 weeks after initial surgery was found to be significantly elevated in the mesorectum compared with the subcutaneous fat, especially in the posterior side (P < 0.05). These findings suggest that the extension of inflammation to the rectal mesentery after the GMT procedure may have strengthened adhesions in the retrorectal space.