Malignant "triton" tumor with metastatic hemangiopericytoma in a patient associated with von Recklinghausen's disease.

An autopsy case of malignant schwannoma in a 31-year-old female associated with von Recklinghausen's disease with unusual elements is reported. The patient who was diagnosed as von Recklinghausen's disease from a biopsy specimen of a subcutaneous tumor in her shoulder and multiple café au lait spots in her chest and back, complained of gradual increase in pain in her lower abdomen. A large mass measuring about 18 cm in diameter was located in her left retroperitoneum. Malignant schwannoma associated with von Recklinghausen's disease was indicated by the cellularity of the tumor, intersecting bundles of spindle cells, alternating cellular and less cellular myxoid areas in the peripheral portion of the tumor, whereas a large part of the tumor had a hemangiopericytoma-like arrangement with gaping blood vessels. In addition, however, foci of rhabdomyosarcomatous differentiation and of angiosarcomatous components were found in some areas of this tumor. Moreover, intravascular schwannian growth, which was presumably related to von Recklinghausen's disease, was observed in the heart and thyroid. This tumor should be classified as a malignant triton tumor because of the presence of rhabdomyoblasts.