Clinicopathological Features Of Uterine Smooth Muscle Tumor Of Uncertain Malignant Potential

Purpose To study the pathologic features,diagnosis and differential diagnosis of smooth muscle tumor of uncertain malignant potential(STUMP).Methods 28 confirmed cases of uterine leiomyosarcomas(LMS)and 40 cases of cellular leiomyomas(CLM)were control groups.Combined with follow-up datas,16 cases of STUMPand 82 cases problem smooth muscle tumors of the uterus were reclassified according with cellularity,cytologic atypia,mitotic activity and necrosis.Immunohistochemical stains for p16,p53,Ki-67 were performed and interstitial vascularity were studied in groups(LMS,CLM,STUMP).The results were compared with each other.Result 98 cases were classified as LMS(n=2),STUMP(n=7),CLM(n=62),leiomyoma(LM)(n=21),atypical leiomyoma(ALM)(n=3)and mitotically active leiomyomas(MAL),respectively.7 patients with STUMP were aged from 17 to 50 years old,averaged(38.57±11.39)years;Tumors were measured for 8 to 18 cm in diameter,averaged(11±3.74)cm.Except for no difference between CLM and LM,the expression of p53 as well as p16 revealed statistically significant differences in LMS,CLM,STUMP and LM(P < 0.05).There was a statistically significant difference for Ki-67 proliferation index expression between LMS and other groups(P < 0.05),but no difference in CLM ? STUMP and LM.LMS is characterristic for thin-walled vessels,which is irregular in shape with teethings as well as branchs and random distribution.It is valuable for diagnosis of LMS that Atypia tumour cells replace endothells in the thin-walled vessels.Nevertheless,thick-walled blood vessels were seen in CLM frequently.The growth of the plexiform thick-walled blood vessels within the tumor stromal were observed in 74.5%(76 /102)CLMs,42.86%(3/7)STUMPs and 80.95%(17/21)LMs,but has not been found in LMSs.Conclusions STUMP is rare.Grasped 3 major diagnostic criteria,combinedwith auxiliary diagnostic indexs including infiltration condition,stromal vascular characteristics and the expression of p53,p16,and Ki-67 is key to correct diagnosis of smooth muscle tumors.