The patient was a 52-year-old woman in whom CT revealed a huge tumor located mainly in the mesenterium. On the 5(th) day, clinical symptoms progressed rapidly and chemotherapy for malignant lymphoma was performed after percutaneous core needle biopsy. However, the patient died on the 9(th) day. After her death, the pathological diagnosis proved to be neuroblastoma based on the core needle biopsy. This disease is extremely rare in adults, but should be taken into consideration since rapid progression may sometimes occur.