Radiology-pathology conference: incidental posterior mediastinal ganglioneuroma

Imaging of Ganglioneuroma: A Literature Review and a Rare Case of Cystic Presentation in an Adolescent Girl

Retroperitoneal ganglioneuroma is a rare neuroectodermal tumor with a benign nature. We performed a literature review among 338 studies. We included 9 studies, whose patients underwent CT and/or MRI to characterize a retroperitoneal mass, which was confirmed to be a ganglioneuroma by histologic exam. The most common features of ganglioneuroma are considered to be a solid nature, oval/lobulated shape, and regular margins. The ganglioneuroma shows a progressive late enhancement on CT. On MRI it appears as a hypointense mass in T1W images and with a heterogeneous high-intensity in T2W. The MRI-"whorled sign" is described in the reviewed studies in about 80% of patients. The MRI characterization of a primitive retroperitoneal cystic mass should not exclude a cystic evolution from solid masses, and in the case of paravertebral location, the differential diagnosis algorithm should include the hypothesis of ganglioneuroma. In our case, the MRI features could have oriented towards a neurogenic nature, however, the predominantly cystic-fluid aspect and the considerable longitudinal non-invasive extension between retroperitoneal structures, misled us to a lymphatic malformation. In the literature, it is reported that the cystic presentation can be due to a degeneration of a well-known solid form while maintaining a benign character: the distinguishing malignity character is the revelation of immature cells on histological examination.

A Rare Case of Giant Mediastinal Ganglioneuroma in A 3-year-old

Ganglioneuroma is a rare, differentiated, and benign neurogenic tumor that could grow into a huge size with minimal or no symptoms at all. Ganglioneuroma is typically found in older children or adults and is commonly detected within the posterior mediastinum (other than retroperitoneal). Here, we present a case of a 3-year-old patient with shortness of breath, and radiological examination showed a giant mediastinal tumor which proved to be a ganglioneuroma after histopathological examination. This study highlights the possibility of ganglioneuroma occurring in younger children and the role of imaging in assessing ganglioneuroma as a posterior mediastinal tumor.

Cause of postprandial vomiting - a giant retroperitoneal ganglioneuroma enclosing large blood vessels: A case report

BACKGROUND

Ganglioneuroma (GN) is a rare neurogenic tumor that accounts for about 0.1%-0.5% of all tumors of the nervous system. It originates from neural crest cells. GN has no specific clinical symptoms or laboratory findings, which leaves it easily overlooked and misdiagnosed as other tumors. Retroperitoneal GN with very large volume and vascular penetration is extremely rare.

CASE SUMMARY

We present the imaging and pathological findings of a giant retroperitoneal GN in a child. A 4-year-old boy had suffered from postprandial vomiting for more than 6 mo with no precipitating factors. Abdominal computerized tomographic examination showed a giant cystic mass in the retroperitoneal area. After injection of contrast agent, the mass showed heterogeneous enhancement. Surgery with local excision of the mass was performed to address the embedded abdominal blood vessels, and the histopathological and immunohistochemical diagnosis of the mass was GN. Postprandial vomiting was relieved, and no complications occurred after the operation.

CONCLUSION

In the diagnosis of giant retroperitoneal hypodense masses in children, GN should be considered if the mass presents delayed enhancement, punctate calcification, and vascular embedding but no invasion. Pathology is the golden standard for the diagnosis of GN, and surgical excision is the optimal treatment for GN.

Imaging Analysis of Ganglioneuroma and Quantitative Analysis of Paraspinal Ganglioneuroma

BACKGROUND This study evaluated the imaging features of ganglioneuroma (GN) and assessed the diagnostic value of the enhancement rate (ER) of CT for GN. MATERIAL AND METHODS We retrospectively reviewed records of 49 patients with histopathologically confirmed GN who underwent preoperative contrast-enhanced CT or MRI between 2010 and 2018. The independent samples t test and chi-square test were used. Receiver operating characteristic (ROC) curves were generated to analyze the diagnostic sensitivity (SE) and specificity (SP). Positive predictive value (PPV) and negative predictive value (NPV) were calculated. RESULTS The CT values were 32.59±3.61 Hounsfield units (HU) for plain scans, 38.87±5.09 HU for the arterial phase, and 54.26±8.14 HU for the venous phase, and the incidence of calcification and cysts was 32.6% and 10.2%, respectively. There was no significant difference in CT results and clinical parameters between mediastinal ganglioneuroma (MGN) and retroperitoneal ganglioneuroma (RGN) (p>0.05). The area under the curves (AUCs) for the arterial enhancement rate (AER), venous enhancement rate (VER), and AER/VER combined index in diagnosing GN were 0.735, 0.980, and 0.990, respectively. The VER of 0.2819 exhibited the SE and SP at 92.9% and 92.9%, respectively, to characterize the GN, whereas the AER of 0.1779 had SE and SP of 52.4% and 90.5%, respectively. The SE and SP for the combined index were 88.1% and 100%, respectively. The GN showed hypointensity on T1WI, hyperintense, or slightly high signal on T2WI with the linear hypointensity, and hyperintense on DWI. CONCLUSIONS A hypodense mass was observed for GN on plain scan and presented delayed enhancement on contrast enhancement. VER or AER/VER combination is more accurate than AER for the diagnosis of paravertebral GN.

Computed tomography and magnetic resonance imaging features of posterior mediastinal ganglioneuroma

PURPOSE

To evaluate computed tomography (CT) and magnetic resonance (MR) imaging findings of posterior mediastinal ganglioneuromas.

MATERIALS AND METHODS

Of 14 pathologically confirmed ganglioneuromas seen in 13 patients, 13 were evaluated by CT images with and without contrast, 11 were evaluated with conventional spin-echo MR images, and 5 were evaluated with contrast-enhanced MR examination. The morphologic features, attenuation, signal intensity, and dynamic enhancement pattern of the neoplasms were evaluated.

RESULTS

All lesions were identified as a well-demarcated oval and/or lobular mass. CT attenuation was predominantly low. Calcification on CT scan was seen in 38% of the cases. Whorled appearance (42%) and tailed-shaped edge (14%) were seen on both CT and MR images. Fat components (29%) observed histologically were also detected in tumors on CT and MR images. MR signal intensity in the lesions was mainly low on T1-weighted images and high on T2-weighted images. Contrast enhancement of the tumors was poor in 46% on dynamic CT study. In all 5 contrast-enhanced MR examinations, all lesions were enhanced.

CONCLUSIONS

The characteristic findings of posterior mediastinal ganglioneuromas are a craniocaudally oblong-shaped mass, calcification, whorled appearance, tail-like extension, and fat component. Poor enhancement on dynamic CT studies is commonly observed.