title: Myofibroblastic sarcomas: a clinicopathological study of 20 cases.
abstract: BACKGROUND
  Myofibroblastic sarcoma was used to be a controversial neoplasm. This study investigated the clinicopathological features of 20 cases of myofibroblastic sarcoma arising in different locations.
  
  
  METHODS
  The paraffin-embedded tissue samples from 20 cases of patients with myofibroblastic sarcoma were stained immunohistochemically, and 5 cases examined by electron microscopy. Student's t test was used to analyze the difference of Ki-67 labeling index between grade 1 and grade 2 myofibroblastic sarcomas.
  
  
  RESULTS
  Histologically, the tumors were composed of slender spindle cells with eosinophilic cytoplasm, and fusiform, tapering, wavy, or plump ovoid; vesicular nuclei and a small central eosinophilic nucleoli. Immunohistochemically, the tumor cells expressed smooth muscle actin (18/20), muscle specific actin (16/20), fibronectin (20/20) and desmin (2/20). Ultrastructurally, the tumor cells revealed abundant rough endoplasmic reticulum and longitudinally arranged fine filaments with focal densities in the cytoplasm. A clinical follow-up of 19 patients showed that 2 cases experienced local recurrence and distant metastasis 6 months to 4 years after the initial operation. Nine cases recurred locally 17 to 46 months after the initial excision, and 9 cases were alive with no evidence of disease.
  
  
  CONCLUSIONS
  Myofibroblastic sarcomas, which exhibit diverse histological appearance, can easily be misdiagnosed as benign tumors. Myofibroblastic sarcomas are local destructive lesions with frequent recurrence, and may metastase distantly.
authors: Department of Pathology and Laboratory of Pathology, West China Hospital, Sichuan University, Chengdu 610041, China.
authors: Guo-zhao
authors: GZ
authors: Meng
authors: Hong-ying
authors: HY
authors: Zhang
authors: Hong
authors: H
authors: Bu
authors: Xian-liang
authors: XL
authors: Zhang
authors: Zong-guo
authors: ZG
authors: Pang
authors: Qi
authors: Q
authors: Ke
authors: Xi
authors: X
authors: Liu
authors: Guo
authors: G
authors: Yang
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D003893:Desmin / Q000032:analysis; D005260:Female; D005354:Fibrosarcoma / Q000737:chemistry / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009217:Myosarcoma / Q000737:chemistry / Q000473:pathology*; D012008:Recurrence; D012983:Soft Tissue Neoplasms / Q000737:chemistry / Q000473:pathology*
chemical_list: D003893:Desmin