Myofibroblastic sarcomas: a clinicopathological study of 20 cases.
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.
Meng
Guo-zhao
GZ
Department of Pathology and Laboratory of Pathology, West China Hospital, Sichuan University, Chengdu 610041, China.
Zhang
Hong-ying
HY
Bu
Hong
H
Zhang
Xian-liang
XL
Pang
Zong-guo
ZG
Ke
Qi
Q
Liu
Xi
X
Yang
Guo
G
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*
D003893:Desmin