Microcystic, elongated and fragmented (MELF) pattern in endometrial carcinoma: clinicopathologic analysis and prognostic implications.

To assess the clinical value of microcystic, elongated, and fragmented (MELF) pattern in Chinese patients with endometrial endometrioid carcinoma. A total of 189 patients with endometrial endometrioid carcinoma were retrospectively analyzed in Peking University Third Hospital from January 2017 to December 2019. We analyzed the association of MELF pattern with the histopathologic data and prognosis of the patients, while immunohistochemistry was performed. The frequency of MELF pattern was 17.99% (34/189). MELF pattern was associated significantly with tumor size, myometrial invasion, histological grade, International Federation of Gynecology and Obstetrics stages, lymphovascular space invasion, and lymph node metastasis. According to multivariate logistic regression analysis, lymphovascular space invasion [95% confidence interval 1.021-48.485, P = .048] was a significant predictor of lymph node involvement. However, MELF pattern was not a significant predictor (95% confidence interval 0.054-2.279, P = .400). Loss of expression for mismatch repair proteins was observed in 10 MELF + cases (29.41%) and 54 MELF- cases (34.84%), respectively. All patients were followed up for 36.8 ± 8.9 months (18-54 months). Only 1 patient with MELF pattern was diagnosed with vaginal recurrence 28 months after the surgery. MELF pattern was associated with adverse histologic findings in endometrial endometrioid carcinomas. However, MELF pattern was statistically not a valuable predictor of lymph node metastasis and it needs more studies to show whether MELF pattern has an impact on the prognosis of patients with endometrial endometrioid carcinoma. MELF pattern may be important for identifying those patients who need comprehensive staging surgery.

Song J ，Li H ，Guo H ，Cai Y ... -  《-》

Clinicopathologic Association and Prognostic Value of Microcystic, Elongated, and Fragmented (MELF) Pattern in Endometrial Endometrioid Carcinoma.

Kihara A ，Yoshida H ，Watanabe R ，Takahashi K ，Kato T ，Ino Y ，Kitagawa M ，Hiraoka N ... -  《-》

[Microcystic, elongated and fragmented invasion pattern in endometrial carcinoma: the clinicopathology analysis].

Zhang XB ，Zhao CL ，Qi XL ，Qin Y ，Wang Y ，Shen DH ... -  《-》

Microcystic, elongated, and fragmented pattern invasion is mainly associated with isolated tumor cell pattern metastases in International Federation of Gynecology and Obstetrics grade I endometrioid endometrial cancer.

Although many studies have evaluated the impact of mismatch repair protein loss of expression (MMR LOE) or microcystic, elongated, and fragmented (MELF) pattern of myometrial invasion as individual factors in endometrial cancer, we analyzed the combined impact of both. We reviewed every case of International Federation of Gynecology and Obstetrics (FIGO) grade 1 endometrioid endometrial cancers (EECs) from our institution, between 2011 and 2015, that had a sentinel lymph node biopsy and/or a lymphadenectomy, and examined the following data: age, myometrial infiltration, MELF infiltration, lymphovascular space invasion, and lymph node status. These cases were then grouped according to the absence of lymph node metastases, the presence of isolated tumor cell (ITC) lymph node metastases, or the presence of non-ITC metastases. Among the 127 cases that were in our study, 105 patients did not have nodal metastases, whereas 22 patients showed metastases, of which 11 were ITC. MMR LOE was only significantly associated with a higher odds ratio (OR) of metastases (OR, 7.44; P < .001). MELF was only associated with a higher OR of ITC-pattern metastases (OR, 32.3; P < .001). This study distinguished the effects of MELF and MMR LOE on the risk of metastases in FIGO grade 1 EEC. Further research on the clinical impact of MELF and ITC-pattern metastases is warranted to better guide clinicians on the management of patients with FIGO grade 1 EEC harboring such characteristics, which are still considered low-risk cancer.

Pelletier MP ，Trinh VQ ，Stephenson P ，Mes-Masson AM ，Samouelian V ，Provencher DM ，Rahimi K ... -  《-》

Is microcystic, elongated, and fragmented pattern of myometrial invasion in endometrioid endometrial carcinoma associated with survival?

Altındağ SD ，Yiğit S ，Şen S 《-》