Malignant Peripheral Nerve Sheath Tumor in Neurofibromatosis Type I : Unusual Presentation of Intraabdominal or Intrathoracic Mass
Case I : A 31 year-old woman with a known neurofibromatosis was admitted complaining of a painful abdominal mass. A physical examination revealed a large, hard soft-tissue mass bulging out from the middle abdomen, and numerous, small subcutaneous neurofibroma nodules and brownish-pigmented lesions (café au lait spots) in the trunk and extremities (). An abdominal CT scan demonstrated a large (approximately 9×10 cm) inhomogeneous mass with an area of central necrosis (). The histopathology of the circumscribed and encapsulated mass obtained by a wide excision indicated a MPNST from the mesentery showing frequent mitoses in more than five per one high power field (). In the immunohistochemical stain, the tumor cells stained positively to the S-100 protein, which is a cytoplasmic marker used for identifying Schwann cells (). One month after surgery, the masses of the right paracolic gutter and the left supravesicle area appeared in the CT scan. The patient was then treated with 6 cycles of MAID chemotherapy (ifosfamide 2000 mg/m2 for 3 days, doxorubicin 20 mg/m2 for 3 days, and dacarbazine 300 mg/m2 for 3 days), which was followed by radiotherapy (5400 cGY). The masses began to disappear after chemoradiotherapy but the disease progressed 2 months later. She was treated with a further 6 cycles of VIP chemotherapy (etoposide 75 mg/m2 for 5 days, ifosfamide 1,000 mg/m2 for 5 days, and cisplatin 20 mg/m2 for 5 days), with a partial response being observed. However, she died as a result of disease progression 21 months after the initial diagnosis.