Introduction/Background Microcystic, elongated, fragmented (MELF) pattern of myometrial invasion is a recently introduced histological pattern detected in some specimens from patients with endometrial carcinoma (EC) with debatable prognostic and predictive effect. The aim of the present study is to examine the role of MELF in the prognosis and survival of patients with EC.

Methodology A total of 4 electronic databases (Medline, Scopus, Google Scholar, and Clinicaltrials.gov) were searched for articles published up to May 2019, along with the references of all articles. All prospective and retrospective trials which reported outcomes of cases with EC who were examined for the presence of MELF pattern were included in the present systematic review.

Results Of the 224 records screened, 15 were considered eligible. Fifteen studies which comprised 785 women were finally included in the systematic review. The correlation between MELF pattern and patients‘ age, tumor grade and stage remained controversial among the included studies. Patients with MELF (+) were detected with larger tumors while lymph node metastasis, lymphovascular space invasion and >50% myometrial invasion were significantly associated with MELF positivity. None of the included studies noted significant difference with regards to disease free survival (DFS) and disease specific survival (DSS) as well as in terms of vaginal recurrence rates. On the other hand, MELF (+) was highlighted as a significant indicator of overall survival.

Conclusion The present study indicates the potential critical role of MELF pattern of myometrial invasion in the detection of lymphovascular space invasion and lymph node metastasis in patients with EC. Regardless, its implication in survival and recurrences still remains elusive and further studies are needed in the field in order to clarify the exact role of MELF in the prognosis and management of EC patients.

Disclosure Nothing to disclose.