分析肺微小脑膜上皮样结节(minute pulmonary meningothelial-like nodules, MPMN)的影像学特点、临床病理学特征。

选择2020年12月至2023年1月我院收治的经病理诊断为MPMN患者42例，分析临床影像学特点、组织形态学表现，采用免疫组化EnVision法检测SSTR2、PR、Vimentin、EMA、CD56、CK(AE1/AE3)、TTF-1、CgA、Syn、SMA、Ki-67的表达情况，复习相关文献。

42例中肺前驱腺体病变及恶性肿瘤伴发23例，肺良性病变伴发8例，无伴发病变11例；肺高分辨CT显示除主要病灶外，42例双肺散在多发微小结节影，术后检出多发MPMN 10例，单发32例，病灶直径<1.0 cm；术中快速冰冻切片及石蜡切片示低倍镜下肺泡间隔增宽，温和上皮样细胞和梭形细胞沿肺间质呈簇状增生，细胞边界不清形成合体样，核圆形或卵圆形，核仁不明显，胞质中等量、淡染，核分裂象罕见，可见核内假包涵体；SSTR2免疫组化阳性21/21例、Vimentin阳性29/29例，PR阳性28/29例，EMA阳性28/32例，CD56阳性18/21例，ER、CK(AE1/AE3)、TTF-1、CgA、Syn、SMA呈阴性，Ki-67阳性指数<1%。

MPMN好发中老年女性，病灶直径小，大部分MPMN为多发性病变；细胞形态及免疫表型与脑膜瘤相似，免疫组化标记SSTR2、PR、CD56、EMA阳性支持诊断。

To analyze the CT imaging characteristics, clinicopathological features, diagnosis and differential diagnosis of minute pulmonary meningothelial-like nodules (MPMNs).

A total of 42 patients with MPMN diagnosed in our hospital from December 2020 to January 2023 were selected. Retrospective analysis of the CT imaging features, histomorphological manifestations. Expression of SSTR2, PR, Vimentin, EMA, CD56, CK (AE1/AE3), TTF-1, CgA, Syn, SMA, Ki-67 was detected by immunohistochemical EnVision method and the relevant literature was reviewed.

In 42 cases, 23 cases were associated with pulmonary precursor adenopathy and malignancy, 8 cases with benign pulmonary lesions and 11 cases without concomitant lesions. High-resolution CT showed scattered to multiple microscopic nodules in both lungs in addition to the main lesion in 42 patients, and post-operatively multiple MPMN were found in 10 cases and single in 32 cases, with lesion sizes <1.0 cm. Both intraoperative frozen sections and paraffin sections showed widened alveolar septa with mild epithelioid and spindle cells proliferating in clusters along the interstitium with indistinct cell borders forming a syncytial pattern, round or ovoid nuclei, inconspicuous nucleoli, moderate cytoplasm, lightly stained, rare nuclear schizophrenia, and intra-nuclear pseudo-inclusion bodies. Immunohistochemical results were positive for SSTR2 (21/21) and vimentin (29/29), positive for PR (28/29), positive for EMA (28/32), positive for CD56 (18/21), and negative for ER, CK (AE1/AE3), TTF-1, CgA, Syn, and SMA were all negative, Ki-67 positivity index was<1%.

MPMN occurs in middle-aged and elderly women, with small lesion diameters, and most MPMN may be multiple lesions. The cell morphology and immunophenotype are similar to meningiomas, and the diagnosis is supported by positive immunohistochemical markers SSTR2, PR, CD56, and EMA.