目的

探讨低级别阑尾黏液性肿瘤（LAMN）与阑尾黏液腺癌（AMAC）的超声图像及实验室检查的差异，以提高诊断准确率。

方法

回顾性分析2009 年1 月至2023 年10 月首都医科大学附属北京天坛医院经手术病理证实的阑尾黏液性肿瘤（AMN）患者的超声及超声造影图像，根据术后病理结果分为LAMN 及AMAC 2 组，采用Fisher 精确概率法对比分析2 组病例超声图像特征和实验室检查（包括感染指标和肿瘤标志物）的差异。

结果

最终46 例患者纳入研究，其中LAMN组29 例，AMAC 组17 例，LAMN 组术前诊断准确率为59%（17/29），而AMAC 组为47%（8/17）。2 组间超声图像特征中肿块性质（囊性/囊实性）、边界、壁结节、钙化、内部回声、洋葱皮样改变、分隔、与周围组织粘连、超声造影表现、是否合并腹膜假黏液瘤（PMP）差异均具有统计学意义（P 均＜0.05）。LAMN 组72%（21/29）的患者肿块呈囊性，28%（8/29）呈囊实性，而AMAC 组100%（17/17）呈囊实性；LAMN 组89%（26/29）肿块边界清晰，AMAC 组76%（13/17）边界不清晰；LAMN 组中14%（4/29）患者有壁结节，AMAC 组中88%（15/17）患者有壁结节；LAMN 组中7%（2/29）患者囊壁有钙化，AMAC 组中59%（10/17）患者囊壁有钙化；LAMN 组52%（15/29）患者内部回声均匀，AMAC 组100%（17/17）患者内部回声均杂乱；LAMN 组34%（10/29）患者肿块内部呈洋葱皮样改变，而AMAC 组均无此征象；LAMN 组14%（4/29）患者肿块内部有分隔，AMAC 组88%（15/17）患者肿块内部有分隔；LAMN 组中7%（2/29）患者肿块与周围组织有粘连，AMAC 组94%（16/17）患者肿块与周围组织有粘连；LAMN 组中7%（2/29）患者肿块超声造影呈高增强，AMAC 组82%（14/17）患者肿块超声造影呈高增强，以厚壁结节样高增强为主，余患者肿块均呈无增强；LAMN 组中7%（2/29）患者合并PMP，AMAC 组65%（11/17）患者合并PMP。AMAC 组肿瘤标志物（癌胚抗原、糖类抗原19-9、糖类抗原125、糖类抗原242、神经元特异性烯醇化酶）升高患者例数多于LAMN 组，2 组间差异均具有统计学意义（P 均＜0.05）。AMAC 组感染指标（白细胞、中性粒细胞、C 反应蛋白）升高患者多于LAMN 组，2 组间差异均具有统计学意义（P均＜0.05）。

结论

LAMN 和AMAC 超声及超声造影表现、血清肿瘤标志物及感染指标均存在一定差异，多项差异特征结合对于提高二者诊断准确率具有较大帮助。

Objective

To investigate the difference in ultrasonographic features and laboratory findings between low-grade appendiceal mucinous tumors （LAMN） and appendiceal mucinous adenocarcinoma （AMAC） in order to improve their diagnostic accuracy.

Methods

The ultrasonographic and contrast-enhanced ultrasound images of patients with appendiceal mucinous tumors confirmed by surgery and pathology at our hospital from January 2009 to October 2023 were retrospectively analyzed. According to the postoperative pathological results， the patients were divided into two groups： patients with LAMNs and those with AMAC. The Fisher exact probability method was used to compare the differences in ultrasound images and laboratory tests（tumor markers and infection indexes） between the two groups.

Results

Forty-six patients were included in the study， including 29 in the LAMN group and 17 in the AMAC group. Preoperative diagnostic accuracy was 59% in the LAMN group and 47% in the AMAC group. There were significant differences in the characteristics of mass （cystic/cystic-solid）， boundary， wall nodule， calcification， internal echo， “onion skin” appearance， septa， adhesion to surrounding tissue， contrast-enhanced ultrasound findings， and whether peritoneal pseudomyxoma （PMP） was combined between the two groups （P＜0.05）. The mass was cystic in 72% （21/29） of patients in the LAMN group and cystic-solid in 28% （8/29）， compared with cystic-solid in 100% （17/17） of patients in the AMAC group. The boundary was clear in 89% （26/29） of patients in the LAMN group and unclear in 76% （13/17） of patients in the AMAC group. Wall nodules were present in 14%（4/29） of patients in the LAMN group and 88% （15/17） in the AMAC group. The capsule wall was calcified in 7% （2/29） of patients in the LAMN group and 59% （10/17） in the AMAC group. Forty-two percent （15/29）of patients in the LAMN group had uniform internal echo， and 100% （17/17） of patients in the AMAC group had chaotic internal echo. Thirty-four percent （10/29） of patients in the LAMN group showed “onion skin”appearance， while no such sign was found in the AMAC group. The masses of 14% （4/29） of patients in the LAMN group and 88% （15/17） in the AMAC group had internal septa. In the LAMN group， 7% （2/29） of patients had adhesion to the surrounding tissue， and in the AMAC group， this percentage was 94% （16/17）.In the LAMN group， 7% （2/29） of the patients showed high enhancement in CEUS， and in the AMAC group，82% （14/17） of the patients showed high enhancement in CEUS， mainly thick-walled nodules， while the masses in the remaining patients showed no enhancement. Peritoneal pseudomyxoma （PMP） was found in 7% （2/29） of patients in the LAMN group and 65% （11/17） in the AMAC group. The number of patients with elevated tumor markers in the AMAC group was higher than that of the LAMN group， and there were statistically significant differences in carcinoembryonic antigen， carbohydrate antigen 199， carbohydrate antigen 125， carbohydrate antigen 242， and neuron-specific enolase between the two groups （P＜0.05）.There were more patients with elevated infection indexes in the AMAC group than in the LAMN group， and there were statistically significant differences in white blood cell count， neutrophils， and C-reactive protein between the two groups （P＜0.05）.

Conclusion

The diagnostic accuracy for LAMNs and AMAC can be significantly improved by ultrasonography and contrast-enhanced ultrasonography combined with serum tumor markers and infection indicators.