Objective: To investigate the clinicopathologic features of microcystic, elongated and fragmented (MELF) pattern invasion of endometrial adenocarcinoma. Methods: HE and immunohistochemistry staining method were used to analysis morphologic features and immunophenotype of 72 patients of endometrial adenocarcinoma with MELF pattern invasion, and chi-square test was used to analysis the clinicopathologic features. Results: The mean age of 72 patients was 54 years (40 to 70 years). Thirty-two patients were pre-menopausal and 40 were post-menopausal. According to the FIGO staging system (2014), 32 cases(44.4%)were at stage Ⅰ, 22 cases(30.6%)at stage Ⅱ, 17 cases(23.6%)at stage Ⅲ and 1 case(1.4%) at stage Ⅳ. Microscopically, MELF invasion showed microcystic, elongated slit-like or fragmented glands in myometrium and their lining cells usually were cube or flat, as well as the single or clusters of eosinophilic tumor cells mimicking histocytes. In addition, a fibromyxoid or inflammatory stromal response was often present.Immunohistochemical staining showed that MELF invasion was positive for p16, CA125 and CA19-9, but negative for ER, PR and p53.Compared with non-MELF pattern invasion, significant differences were noted in menopause pausimenia, FIGO stages, deep invasion into myometrium, lymph metastasis, lymphovascular space invasion (LVSL), serum CA125 and CA19-9 in patients with MELF pattern invasion (all P<0.05). Conclusions: MELF pattern invasion of endometrial adenocarcinoma is characterized by advanced FIGO stage, deep myoinvasion, high metastasis rate to lymph node and LVSL. Pathologists should recognize the MELF invasion and evaluate the depth of myometrium of infiltration and LVSL with special attention to the presence of MELF invasion with necessary immunohistochemistry for more accurate pathological diagnosis.
目的： 探讨伴微囊性、伸长及碎片状(microcystic，elongated and fragmented，MELF)浸润方式子宫内膜样腺癌的临床病理特征。 方法： 收集72例伴MELF浸润方式的子宫内膜样腺癌患者临床资料，采用HE染色和免疫组织化学分析其组织形态学特点及免疫表型，采用χ(2)检验分析临床病理特征。 结果： 72例伴MELF浸润方式的子宫内膜样腺癌患者年龄范围40～70岁(平均年龄54岁)；32例为绝经前女性，40例为绝经后女性。国际妇产科联盟(FIGO)分期为Ⅰ期32例(44.4%)，Ⅱ期22例(30.6%)，Ⅲ期17例(23.6%)，Ⅳ期1例(1.4%)。MELF浸润方式镜下表现为微囊、拉长裂隙样或碎片状腺体浸润肌层，内衬立方或扁平上皮，也可见单个或小簇状嗜酸性胞质肿瘤细胞，类似于组织细胞。通常伴有纤维黏液样间质或富含炎性细胞间质。免疫组织化学显示MELF浸润腺体雌激素受体、孕激素受体、p53阴性，p16、CA125、CA19－9阳性。与不伴MELF浸润方式的子宫内膜样腺癌相比较，两组在是否绝经、FIGO分期、子宫肌层浸润深度、淋巴结转移、淋巴管血管侵犯、血CA125和CA19－9水平差异有统计学意义(均P<0.05)。 结论： 伴MELF浸润方式的子宫内膜样腺癌的危险因素为FIGO分期晚、子宫深肌层浸润、淋巴结转移率高及淋巴管血管侵犯，其特殊的病理形态常具有隐弊性。病理医师应提高对MELF浸润方式的认识并仔细评估肌层浸润深度及淋巴管血管侵犯，结合免疫组织化学为临床提供更为准确的病理诊断。.
Keywords: Diagnosis, differential; Endometrial neoplasms; Immunohistochemistry.