Recurrent retroperitoneal malignant nerve sheath tumor associated with neurofibromatosis type 1 responding to carboplatin and etoposide combined chemotherapy.

A 25-year-old man was referred to our hospital with left flank pain, and computed tomography (CT) and magnetic resonance imaging (MRI) revealed large retroperitoneal masses. Physical examination revealed many café-au-lait spots and superficial neurofibromas, and a diagnosis of neurofibromatosis type 1 (von Recklinghausen's disease) was made. The tumor was resected, and the pathological diagnosis was malignant peripheral nerve sheath tumor (MPNST). Six months after the operation, lung metastases were detected. Surgical resection was incomplete, as there were too many lesions. He received four courses of chemotherapy with carboplatin and etoposide, and the metastatic lung lesions were markedly decreased. After chemotherapy, complete resection of the remaining lung lesions was performed, and there has been no recurrence to date.