Introduction

The retrocrural space (RCS) is a small triangular region located at the lowermost part of the posterior mediastinum, bounded by two diaphragmatic crura. The occurrence of a tumor in the RCS is rare; however, various types of tumors can arise in this region. Posterior mediastinal tumors are difficult to diagnose before surgery, and due to the characteristics of the RCS, accessing it via nonsurgical imaging biopsy is challenging.

We report a case of an RCS tumor that was successfully resected using video-assisted thoracoscopic surgery (VATS). The tumor was identified as a capillary hemangioma, which is extremely rare among RCS tumors.

Case

Ethical statements: This study was approved by the Institutional Review Board (IRB) of Daegu Catholic University Medical Center (IRB No. CR-23-058) and the need for informed consent was waived.

A 79-year-old male patient was followed up in the department of rehabilitation medicine at Daegu Catholic University Medical Center for left middle cerebral artery infarction. He was referred to the department of chest surgery for an enlarged retrocrural mass found on contrast-enhanced chest computed tomography (CT) while being examined for pneumonia. Contrast-enhanced chest CT showed a right retrocrural mass with a size of 3.6×2.2 cm with peripheral enhancement (Fig. 1). The mass was considered a probable paraganglioma and required differential diagnosis from Castleman disease. In the contrast-enhanced chest CT performed 2 years ago, the mass size was 2.6×1.9 cm. He had no symptoms either prior to the increase in mass size or after its enlargement over time. Due to an increase in the mass size, magnetic resonance imaging (MRI) was performed to obtain more information necessary for the decision to perform surgery. It was an enhancing mass showing T2-high signal intensity on MRI, and the presumptive diagnoses were paraganglioma and neurogenic tumor (Fig. 2).

To diagnose paraganglioma, 24-hour urine fractionated metanephrines and catecholamines, as well as plasma fractionated metanephrines and catecholamines, were tested and found to be within the normal range. In addition, an abnormal uptake was not observed on the metaiodobenzylguanidine scan. As a result, paraganglioma was ruled out, and tumor resection was performed without any special preoperative treatment.

VATS was performed, and the patient was placed in the left decubitus position to allow access to the right thorax. A 5-mm scope was used to perform the surgery with three ports positioned at the 5th intercostal space anterior axillary line, 5th intercostal space posterior axillary line, and 7th mid-axillary line to allow for a useful approach to the RCS. The camera was inserted through the port at the 5th intercostal space anterior axillary line. An approximately 3-cm purple-red mass was identified between the vertebra and the aorta. The mass was dissected without invasion of adjacent organs, and a 24 French chest tube was inserted before completing the surgery. The mass was pathologically diagnosed as a capillary hemangioma (Fig. 3).

On postoperative day 3, the chest tube was removed, but the patient had difficulty moving due to left hemiplegia; thus, he could not be discharged from the hospital. Therefore, all stitches were removed, and it was decided to wait until the permanent biopsy results were available before the patient could be discharged. On postoperative day 15, the patient was finally discharged without any significant complications.

Discussion

The RCS is a small triangular region located at the lowermost part of the posterior mediastinum and bounded by two diaphragmatic crura. This space includes the aorta, nerves, azygos vein, hemiazygos vein, thoracic duct, and lymph nodes [1]. The occurrence of a tumor in the RCS is rare; however, various types of tumors can arise in this region. Neoplasms that arise in the RCS can be classified into neurogenic tumor, germ cell, lymphoid tumor, and mesenchymal tumor based on the origin of the cells. Retrocrural neurogenic tumors include neuroblastoma, neurofibroma, and paraganglioma, whereas germ cell tumors include teratoma and metastatic seminomatous and nonseminomatous malignant germ cell tumors. Lymphoma can involve retrocrural lymph nodes as a lymphoid tumor, and lipoma and liposarcoma can occur as tumors originating from mesenchymal cells [1]. Hemangioma is a benign tumor characterized by a proliferation of normal vascular elements, resulting in a highly vascular structure. Hemangiomas in the mediastinum are rare, accounting for less than 0.5% of all mediastinal tumors; they also rarely arise in the posterior mediastinum [2,3]. Hemangiomas can be classified into capillary, cavernous, and venous types based on their size. The majority of hemangiomas are of the cavernous or capillary type [3,4]. Contrast-enhanced CT and MRI can be helpful in diagnosing hemangioma. The dynamic contrast-enhanced CT finding of a capillary hemangioma in the lesser omentum may indicate peripheral enhancement in the dynamic bolus phase and isoattenuated fill-in in the delayed phase. However, some studies have demonstrated that it may exhibit contrast density similar to that of the aorta during the arterial phase [5]. On MRI, T1-weighted images showed similar signal intensities between the hemangioma and muscle, whereas T2-weighted images showed higher signal intensity in the hemangioma than in the muscle, which could be helpful in the diagnosis [3]. However, the signal of capillary hemangioma may appear less high due to varying degrees of fibrosis and hemosiderin deposition leading to shrinkage [5].

Posterior mediastinal tumors, including mediastinal hemangiomas, are difficult to diagnose before surgery [3]. Due to the characteristics of the RCS, it is difficult to access via nonsurgical imaging biopsy. Therefore, although clear surgical treatment guidelines for RCS masses have not been established, surgical resection remains essential for definitive diagnosis and treatment. Tumor resection in the RCS is a challenging process [6,7]. This is because complications that can arise from damage to surrounding structures can be catastrophic. These complications include massive bleeding due to major vessel injury, diaphragm elevation due to phrenic nerve injury, chyle leak due to thoracic duct damage, and paraparesis or paraplegia due to damage to intercostal arteries with spinal branches [6-8]. If the size of capillary hemangioma in the RCS increases, surgical resection should be considered to differentiate it from other malignancies that may occur in this region. VATS in the RCS can be a great approach owing to its advantages, such as an enlarged surgical view of the deep field of the thorax, decreased wound size, reduced postoperative pain, less intraoperative blood loss, short chest tube drainage period, and short recovery time [9].

Article information

Conflicts of interest

No potential conflict of interest relevant to this article was reported.

Funding

None.

Author contributions

Conceptualization: CHL, YHJ. Data curation: HSL. Investigation: HSL, THY. Validation: YHJ. Visualization: THY. Project administration: YHJ. Writing-Original draft: HSL, CHL, YHJ. Writing-review & editing: HSL, THY, YHJ. All authors read and approved the final manuscript.

Fig. 1.

Contrast-enhanced chest computed tomography. Axial (A) and coronal (B) views reveal a right retrocrural mass (arrows) that measured 3.6 cm with enhancement.

Fig. 2.

Magnetic resonance imaging. A mass in the prevertebral area at the T10–T11 level (arrows) with (A) low signal intensity on T1 and (B) high signal intensity on T2. (C) The mass (arrow) shows enhancement on contrast-enhanced fat-suppressed fast-spin echo T1-weighted magnetic resonance imaging.

Fig. 3.

(A) Gross image of the purple-red-colored hemangioma measuring about 3 cm. (B) Capillary hemangioma. There are small vessels lined with endothelial cells (hematoxylin & eosin, ×200). (C) The endothelial cells are positive for CD34 immunohistochemical staining (×200).

References

• 1. Restrepo CS, Eraso A, Ocazionez D, Lemos J, Martinez S, Lemos DF. The diaphragmatic crura and retrocrural space: normal imaging appearance, variants, and pathologic conditions. Radiographics 2008;28:1289–305.ArticlePubMed
• 2. Zeyaian B, Soleimani N, Geramizadeh B. Posterior mediastinal capillary hemangioma misdiagnosed as neurofibromas: a rare case report and review of the literature. Rare Tumors 2015;7:5639.ArticlePubMedPMCPDF
• 3. Yoshino N, Okada D, Ujiie H, Akiyama H, Nishimura Y, Koizumi K, et al. Venous hemangioma of the posterior mediastinum. Ann Thorac Cardiovasc Surg 2012;18:247–50.ArticlePubMed
• 4. McAdams HP, Rosado-de-Christenson ML, Moran CA. Mediastinal hemangioma: radiographic and CT features in 14 patients. Radiology 1994;193:399–402.ArticlePubMed
• 5. Nagano H, Goi T, Taguchi S, Tsubaki T, Tsuchiyama T, Uematsu H, et al. Capillary hemangioma arising from the lesser omentum in an adult: a case report. Medicine (Baltimore) 2020;99:e18693.ArticlePubMedPMC
• 6. Sponholz S, Trainer S, Schirren M, Schirren J. Resection of retrocrural germ cell tumor metastases: two surgical approaches. J Thorac Cardiovasc Surg 2019;157:2482–9.ArticlePubMed
• 7. Kesler KA, Kruter LE, Perkins SM, Rieger KM, Sullivan KJ, Runyan ML, et al. Survival after resection for metastatic testicular nonseminomatous germ cell cancer to the lung or mediastinum. Ann Thorac Surg 2011;91:1085–93.ArticlePubMed
• 8. Kesler KA. Surgical techniques for testicular nonseminomatous germ cell tumors metastatic to the mediastinum. Chest Surg Clin N Am 2002;12:749–68.ArticlePubMed
• 9. Khanh HQ, Van Khoi N, Vuong NL. Long-term outcome in mediastinal malignancies: video-assisted thoracoscopic versus open surgery. Indian J Thorac Cardiovasc Surg 2021;37:44–52.ArticlePubMedPMCPDF

Figure & Data

References

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