正电子发射断层扫描/计算机断层扫描（PET/CT）鉴别可切除胸腺瘤和前纵隔淋巴瘤 ...

正电子发射断层扫描/计算机断层扫描（PET/CT）鉴别可切除胸腺瘤和前纵隔淋巴瘤

Positron emission tomography/computed tomography differentiates resectable thymoma from anterior mediastinal lymphoma

目的：孤立性前纵隔肿块常包括胸腺瘤或淋巴瘤。淋巴瘤为非手术治疗，需要活检。由于穿刺可能会加重胸膜转移，因此非侵袭性胸腺瘤常为手术切除，且无需活检。这项研究旨在确定临床标准或PET/CT是否可以准确鉴别这两种疾病，从而指导直接手术与活检决策。

方法：回顾性分析2006年至2019年治疗的48例可切除胸腺瘤和29例前纵隔淋巴瘤。所有患者治疗前都进行了PET/CT检查，且肿块表现为可切除（孤立性，无明显的侵袭或转移）。使用Wilcoxon秩和检验、卡方检验和逻辑回归评估临床标准（年龄和B症状）和PET/CT最大标准化摄取值鉴别胸腺瘤和淋巴瘤的可靠性。采用受试者操作特征分析确定与胸腺瘤最相关的最大标准化摄取值阈值。

结果：胸腺瘤和前纵隔淋巴瘤的肿瘤类型和年龄组之间无相关性（P=0.183）。胸腺瘤患者报告B症状的可能性较小（P＜0.001）。胸腺瘤和淋巴瘤的中位最大标准化摄取值差异显著：4.35和18.00（P＜.001）。在多变量回归中，最大标准化摄入值与肿瘤类型独立相关。在受试者操作特征分析中，较低的最大标准化摄取值与胸腺瘤有关。最大标准摄取值小于12.85与胸腺瘤相关，敏感性为100.00%，阳性预测值为88.89%。小于7.50的最大标准摄取值提示胸腺瘤的阳性预测值为100.00%。

结论：PET/CT可切除前纵隔肿块的最大标准化摄取值可能有助于指导直接手术与活检的决定。最大标准摄取值小于7.50的肿瘤可能是胸腺瘤，因此可能在不进行活检的情况下进行适当的切除。最大标准摄取值大于7.50的肿瘤应进行活检以排除淋巴瘤。淋巴瘤的最大标准摄取值可能大于12.85。

Objective: Discrete anterior mediastinal masses most often represent thymoma or lymphoma. Lymphoma treatment is nonsurgical and requires biopsy. Noninvasive thymoma is ideally resected without biopsy, which may potentiate pleural metastases. This study sought to determine if clinical criteria or positron emission tomography/computed tomography could accurately differentiate the 2, guiding a direct surgery versus biopsy decision.

Methods: A total of 48 subjects with resectable thymoma and 29 subjects with anterior mediastinal lymphoma treated from 2006 to 2019 were retrospectively examined. All had pretreatment positron emission tomography/computed tomography and appeared resectable (solitary, without clear invasion or metastasis). Reliability of clinical criteria (age and B symptoms) and positron emission tomography/computed tomography maximum standardized uptake value were assessed in differentiating thymoma and lymphoma using Wilcoxon rank-sum test, chi-square test, and logistic regression. Receiver operating characteristic analysis identified the maximum standardized uptake value threshold most associated with thymoma.

Results: There was no association between tumor type and age group (P = .183) between those with thymoma versus anterior mediastinal lymphoma. Patients with thymoma were less likely to report B symptoms (P < .001). The median maximum standardized uptake value of thymoma and lymphoma differed dramatically: 4.35 versus 18.00 (P < .001). Maximum standardized uptake value was independently associated with tumor type on multivariable regression. On receiver operating characteristic analysis, lower maximum standardized uptake value was associated with thymoma. Maximum standardized uptake value less than 12.85 was associated with thymoma with 100.00% sensitivity and 88.89% positive predictive value. Maximum standardized uptake value less than 7.50 demonstrated 100.00% positive predictive value for thymoma.

Conclusions: Positron emission tomography/computed tomography maximum standardized uptake value of resectable anterior mediastinal masses may help guide a direct surgery versus biopsy decision. Tumors with maximum standardized uptake value less than 7.50 are likely thymoma and thus perhaps appropriately resected without biopsy. Tumors with maximum standardized uptake value greater than 7.50 should be biopsied to rule out lymphoma. Lymphoma is likely with maximum standardized uptake value greater than 12.85.