[Retroperitoneal malignant peripheral nerve sheath tumor (MPNST) complicated with von Recklinghausen's disease: a case report].

A retroperitoneal malignant peripheral nerve sheath tumor (MPNST) in a patient with von Recklinghausen's disease is reported. A 55-year-old woman was admitted with a left side abdominal mass. Physical examination showed numerous cafe-au-lait-spots, subcutaneous masses, scoliosis, and a baby's head-sized fixed mass in the left abdomen. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a 9 x 9 cm retroperitoneal mass. Two other tumors were also found. One on the left side of the T2-T3 thoracic spine, and the other posterior to the right hip joint. The retroperitoneal tumor was resected en bloc. The tumor was a solid yellow mass. Macroscopically it has a pseudocapsule of fibrous tissue, weighed 1,120 g and measured 9 x 9 x 15 cm. The histopathological diagnosis was malignant peripheral nerve sheath tumor (MPNST). Since the responsiveness of these tumors to chemotherapy and radiation therapy is poor, we did not administer adjuvant therapy. The patient is alive with no evidence of recurrence more than 6 months after surgey.