Rationale: A primary primitive neuroectodermal tumor (PNET) is a rare and highly malignant tumor that often occurs in the central nervous system of children and young adults. This tumor is rarely observed in the bladder.
Patient concerns: In this paper, we describe the case of a 64-year-old man with a PNET of the bladder. He experienced dull pain in the lower left abdomen for 5 months (without any obvious inducement), which gradually became aggravated and intolerable.
Diagnoses: Partial cystectomy was performed, and a PNET of the bladder, which is extremely rare, was confirmed.
Interventions: Following cystectomy, the patient's general postoperative state was poor and he could not tolerate chemotherapy. Thus, he was subjected to pelvic radiotherapy for 2 weeks.
Outcomes: His physical condition did not improve significantly after radiotherapy; however, we still plan to continue it. If the patient's physical condition improves, chemotherapy will be considered.
Lessons: Most cases of PNETs are intravesical or at least mainly endophytic. However, in this case, the mucosal layer was barely involved, and the tumor mainly grew out of the bladder, which is very rare. The present case provides reference for the diagnosis of PNET.