zd46 copy.JPG (37286 bytes) 46.This large fleshy mass arose in the retroperitoneum and is an example of a sarcoma. Sarcomas arise from mesenchymal tissues. This one happened to be a "malignant fibrous histiocytoma" which is a wastebasket term for sarcomas that do not resemble mesenchymal cells such as striated muscle (rhabdomyosarcoma), smooth muscle (leiomyosarcoma), fat (liposarcoma), blood vessels(angiosarcoma), bone (osteosarcoma), or cartilage (chondrosarcoma). Sarcomas are big and bad.

46.图示大块肉样组织为腹膜后神经瘤，来源于间充质组织。该肿瘤旧称“恶性纤维性组织细胞瘤”，不同于来源于间充质细胞的肉瘤，如:横纹肌（横纹肌肉瘤），平滑肌（平滑肌肉瘤），脂肪（脂肪肉瘤），血管（血管肉瘤），骨（骨肉瘤），软骨（软骨肉瘤）。肉瘤很大，恶性高。