Retroperitoneal malignant schwannoma and peritoneal malignant mesothelioma: a case report.

Malignant schwannoma and peritoneal malignant mesothelioma (MM) are very rare tumors. Schwannoma or neurilemmoma-benign or malignant-do not arise from the nerves, but from the supporting Schwann cells. Malignant peripheral nerve sheath tumors (MPNSTs) commonly are large in size. They are painful and may cause many different symptoms depending on their location and size. MM arises primarily from the surface serosal cells of the pleural, peritoneal, and pericardial cavities. A malignant schwannoma was diagnosed in a 52-yearold woman, which was surgically treated. After a 17-month disease-free interval, local recurrence was diagnosed. The patient was operated on for second time and MM was diagnosed as second primary tumor, along with recurrence of the malignant schwannoma. The patient received postoperative adjuvant external beam radiotherapy and chemotherapy. Despite combined-modality treatment the disease progressed and the patient was operated on for third time 2.5 years after the first operation with partial tumor resection. She died 3 years after the first diagnosis. Early diagnosis of these two types of tumors is very difficult because of unspecific clinical symptoms. Singlemodality therapy of these tumors has shown poor results. Combined-modality approaches have shown some benefits, but further studies are required.