Genital tract and perineal electrical burns during resectoscopic surgery are occasionally encountered. However, perineal or buttock burns from other causes have not been reported.A 44-year-old overweight woman with a history of menometrorrhagia underwent endometrial ablation with a thermal balloon device uneventfully under general anesthesia. Upon removal of the weighted speculum it was noted that the buttocks had sustained two oval burns under the speculum ball. Experiments demonstrated that the weighted speculum cools off differentially, with the ball temperature remaining at higher than 45C in room air for at least 30 minutes after autoclaving.The use of the weighted speculum within 30 minutes of autoclaving may result in buttock burns. The speculum cools to lower than 40C within 1 minute when rinsed or bathed with at least 1 L of saline solution.