International Journal of Hematology and Oncology 2021, Vol 31, Num 3 Page(s): 139-147
Clinical Significance of the MELF Pattern Myometrial Invasion in Low Grade Endometrioid Type Endometrial Carcinoma

Nejat OZGUL1, Fatma Oz ATALAY2, Gokhan BOYRAZ1, Alp USUBUTUN2, Utku AKGOR1, Murat GULTEKIN1, Mehmet Coskun SALMAN1

1Hacettepe University, Faculty of Medicine, Division of Gynecologic Oncology, Ankara, TURKEY
2Hacettepe University Faculty of Medicine, Department of Pathology, Ankara, TURKEY

Keywords: Endometrial cancer, Endometrioid type endometrial cancer, Myometrial invasion, MELF pattern
The majority of cases with endometrial cancer (EC) have low grade endometrioid type disease which has a favorable prognosis. However, a subgroup of these patients shows a more aggressive clinical course. There are several risk factors defined for the aggressive course including tumor diameter, cervical involvement, depth of myometrial invasion, and lymphovascular space invasion. The morphologic pattern of myometrial invasion was also suggested to be one of the risk factors associated with unfavorable prognosis in these patients. A retrospective study was conducted to investigate the role of microcystic elongated and fragmented (MELF) pattern of myometrial invasion (MI) in patients with low grade endometrioid type EC. Of 276 cases, 69 (25.0%) had MELF pattern of MI. The rate of lymph node metastasis was higher in patients with MELF pattern of MI which was an independent risk factor for lymphatic dissemination (p< 0.001). Also, MELF pattern of MI was significantly associated with decreased disease-free survival (DFS) (p= 0.015). In conclusion, in patients with low grade endometrioid type EC, the presence of MELF pattern of MI is associated with the more aggressive clinical course since it is associated with higher rate of lymphatic metastasis and decreased disease-free survival.