Objective: To investigate the clinicopathological features, diagnosis and differential diagnosis of ectopic meningothelial hamartoma (EMH). Methods: Three cases of EMH diagnosed in the First Affiliated Hospital of Nanjing Medical University from January 2014 to December 2020 were enrolled. All cases were evaluated by clinical and imaging features, HE and immunohistochemical staining, and the relevant literature was reviewed. Results: There were one male and two female patients, aged 2, 67 and 19 years, respectively. Clinically, they presented as skin masses in the head and face region (two cases) and sacro-coccygeal region (one case). Grossly, the lesions ranged in size from 1.6 cm to 8.9 cm. Microscopically, the lesions were ill-defined, and located in the dermis and subcutis, and showed pseudovascular channels lined by monolayer of cuboidal to flattened epithelium with mild atypia, with variable cystic cavity formation. There was prominent interstitial fibrosis. Concentric, lamellated, onion skin-like arrangement with short spindle or ovoid cells and psammoma bodies were noted. Immunohistochemically, these cells were strongly positive for SSTR2, EMA, vimentin and progesterone receptor. Ki-67 positive index was low, approximately 1%. Conclusions: EMH is uncommon. Definitive diagnosis relies on histopathologic examination. The importance in recognizing the lesions is to differentiate from other more aggressive tumors.
目的： 探讨异位性脑膜上皮错构瘤（ectopic meningothelial hamartoma，EMH）临床病理特征、诊断及鉴别诊断要点。 方法： 收集2014年1月至2020年12月南京医科大学第一附属医院收治的经病理确诊的EMH 3例，观察其临床及影像学表现，分析其组织学、免疫组织化学结果，并复习相关文献。 结果： 患者男性1例，女性2例，年龄分别为2、67和19岁。临床表现为皮肤肿块，其中头面部2例，骶尾部1例。病变最大径1.6~8.9 cm，镜下病变界限不清，位于真皮及皮下，均可见特征性的假血管腔隙样结构及不同程度的囊腔形成，腔隙及囊腔表面衬覆单层立方或扁平上皮，异型性轻微，间质胶原纤维明显增生。局灶可见短梭形、卵圆形细胞形成同心圆、洋葱皮样结构及钙化沙砾体。免疫组织化学病变细胞表达生长抑素Ⅱ型受体、上皮细胞膜抗原、波形蛋白、孕激素受体，Ki-67阳性指数低，约1%。 结论： 异位性脑膜上皮错构瘤罕见，确诊依赖术后病理，认识这类疾病的重要性在于与其他更具侵袭性的肿瘤性病变相区分。.