A Case of Retroperitoneal Primary Neuroblastoma that Developed in Adulthood

Abstract

Neuroblastoma is a solid malignant tumor found in young children period, but it may also develop in adulthood. Adult neuroblastoma is rare in Japan (incidence of at least 1/100 million). Here, we report on an adult with retroperitoneal primary neuroblastoma. A 32-year-old woman presented with a chief complaint of abdominal tumor diagnosed as neuroblastoma on needle biopsy. The tumor markers for neuroblastoma were 32.6 ng/ml for neuron specific enolase, 30.1 μg/mg Cr for urine vanillylmandelic acid and 42.3 μg/mg Cr for urine homovanillic acid. Imaging showed metastasis to the mediastinal lymph nodes, but bone metastases were not found. The International Neuroblastoma Risk Group Staging System classification for this neuroblastoma was stage M. The tumor involved the left renal artery and aorta. The case was positive for image defined risk factors. Therefore, the patient received three courses of cyclophosphamide, pirarubicin, vincristine, and cisplatin. Tumor shrinkage was noted. We recommended continued chemotherapy, and bone marrow transplantation, but the patient refused further chemotherapy due to the serious side effects of chemotherapy. Tumor extirpation was judged possible by resection of the left renal tumor using a retroperitoneal mirror in combination. The excised tumor was more ganglion-like than at biopsy, and a stroma-rich portion was recognized, which was thought to be maturation due to chemotherapy. MYCN gene amplification was absent. Postoperatively, radiotherapy of the tumor bed and mediastinal lymph nodes was performed and the patient was followed-up. Many adults refuse chemotherapy, which makes sufficient treatment difficult. In adults, even when MYCN gene amplification is not allowed, sufficient observation is necessary since prognosis is the poor.