We present a 17-year-old man who was diagnosed as "central nervous system teratoma" more than half a year ago, with symptoms of numbness and weakness of both lower limbs. The patient was bedridden since December 2019, accompanied by dysuria and fecal incontinence. In February 2020, an erythema of 8 cm X 5 cm was found in the lumbosacral area during chemotherapy. The erythema was red, without itching and pain, diagnosed as "stage I pressure ulcer"(5). The pressure ulcer was disinfected, changed dressings regularly, without other special treatment. In July 2020, the patient was given whole brain and spinal cord radiotherapy for central nervous system teratoma in our department. The pressure ulcer in the lumbosacral area had formed a circular cavity with a size of 3 cm X 3 cm. There are tan necrotic tissue that adheres to the wound bed, with heavy amount of exudate, without itching, pain or granulation tissue coveraged. The PUSH scale score was 15(6) (Fig. 1). The pressure ulcer was treated with iodophor disinfection plus the external application of sulfadiazine regularly, but the wound heals poorly. On July 25th, the patient had a high fever during the radiotherapy suddenly, with a body temperature of 40.1 degrees Celsius. Laboratory results showed C-reactive protein [(CRP) 242.97 mg/liter, normal:0–7 mg/liter], Procalcitonin[(Plt) 1.500 ng/ml, normal: <0.150 ng/ml], and white blood cell count[(WBC)6.4 × 10^9/L, nomal:4–10 × 10^9]. The increased values of the inflammation index suggested the possibility of pressure ulcer co-infection. There was no decrease in body temperature after Levofloxacin combined with ornidazole and Supushen were used for anti-infection treatment. So the anti-infective drugs were upgraded to Tyneng combined with levofloxacin, then the body temperature decreased gradually. Laboratory results showed C-reactive protein [(CRP) 103.12 mg/liter, normal:0–7 mg/liter], Procalcitonin[(Plt) 0.517 ng/ml, normal: <0.150 ng/ml], and white blood cell count[(WBC)12 × 10^9/L, nomal:4–10 × 10^9], indicated the treatment was effective. However, the uncured pressure ulcer was still a potential source of infection. On July 30th, after obtained informed consent, we tried to irradiate the posterior lumbosacral pressure ulcer with 3D-CRT using a 6 MV photon beam. The patient was placed in a prone position and a total dose of 50 cGy was administered (Fig. 2, 3).