Surgical approach for thymic epithelial tumor

Usefulness of positron-emission tomography for predicting the World Health Organization grade of thymic epithelial tumors

Background

It is often difficult to distinguish between thymoma and thymic carcinoma by preoperative radiological tests. While there have been some reports that the maximum standardized uptake value (SUV_max) in positron emission tomography‐computed tomography (PET‐CT) is useful to this end, no large‐scale analysis has been performed. We therefore analyzed the usefulness of the SUV_max and tumor size (TS) for differentiating thymic epithelial tumors.

Methods

From 2011 to 2019, 129 patients with thymic epithelial tumor who underwent PET‐CT before surgical treatment were enrolled. The relevance of the SUV_max to the World Health Organization (WHO) histological type was assessed. To reduce the impact of the TS, the ratio of the SUV_max to the TS was also investigated.

Results

A total of 99 thymoma cases and 30 thymic carcinoma cases were enrolled into the study. The SUV_max and SUV_max/TS of thymic carcinoma were significantly higher than those of thymoma (SUV_max: 7.7 ± 3.4 vs. 3.3 ± 1.3, p < 0.01; SUV_max/TS: 1.5 ± 0.7 vs. 0.6 ± 0.4, p < 0.01). Focusing on the patients with a moderate SUV_max of ≤5 (84 thymoma and 4 thymic carcinoma), the SUV_max/TS values of thymic carcinoma were still significantly higher than those of thymoma (1.6 ± 0.8 vs. 0.6 ± 0.4, p < 0.01).

Conclusions

PET‐CT might provide significant information for differentiating images of thymoma and thymic carcinoma. We experienced several cases of thymic carcinoma with a moderate SUV_max of ≤5, and SUV_max/TS was considered a useful parameter for differentiating such cases.

Hemi-Clamshell Approach for Fetal Lung Interstitial Tumor Resection in a Neonate: A Case Report

Fetal lung interstitial tumor (FLIT) is a rare primary lung mass in neonates. Classical incisions, such as posterolateral thoracotomy or median sternotomy, do not provide optimal exposure of the operative field for the resection of pediatric thoracic giant tumors. Herein, we report a rare case of a FLIT in a full-term male neonate, with complete resection achieved using a hemi-clamshell approach, which provided the required visualization of the operative field. The neonate was transferred to our hospital because of mild respiratory distress, which developed 18-hour after normal vaginal delivery. A mass in his right chest, without a midline shift, was observed on chest radiographs. Computed tomography showed a well-circumscribed solid anterior cervicothoracic mass, with a uniform density and no apparent cysts, diagnosed as a primary thoracic giant tumor. Once the patient was clinically stabilized, we proceeded with right upper lobectomy, using a hemi-clamshell approach, full sternotomy, and anterolateral thoracotomy, on postnatal day 22.

Histopathologic examination revealed an 8.5 × 6.5 × 4.0 cm solid mass within the right upper lobe, which was diagnosed as a FLIT. His postoperative recovery was uneventful. The patient was followed up for 1 year, with no complaints or symptoms and no postoperative shoulder dysfunction. Gross total resection of primary thoracic giant tumors can be accomplished in neonates with optimal exposure of the chest cavity using a hemi-clamshell approach.

Surgical management of thymic epithelial tumors

Resection is the mainstay of treatment for thymic epithelial tumors (TETs), with complete removal of the tumor and involved organs being the ultimate aim. The choice of surgical approach plays a major role in defining treatment success, and the optimal choice of method should thus provide an adequate surgical view to achieve complete tumor resection. While median sternotomy is considered the gold standard for access to the mediastinum, several minimally invasive approaches to thymectomy have been described, including video-assisted robotic-assisted thymectomy, although the oncological outcomes of that procedure remain unclear. A multimodal approach incorporating chemotherapy or chemoradiotherapy followed by extended surgery may improve resectability and outcomes for patients with advanced TETs. Surgical debulking is also reportedly acceptable for invasive thymoma because of its potential for achieving favorable outcomes. Re-resection is an acceptable option for patients with recurrent thymoma after initial resection, and repeat resection for recurrent pleural dissemination seems effective. Here, the literature on current clinical practices in the surgical management and treatment of TETs is reviewed.