Superior cervical ganglion mimicking retropharyngeal adenopathy in head and neck cancer patients: MRI features with anatomic, histologic, and surgical correlation

Are superior cervical sympathetic ganglia avid on whole body 68Ga-PSMA-11 PET/magnetic resonance?: a comprehensive morphologic and molecular assessment in patients with prostate cancer

OBJECTIVES

Recent reports warn against erroneous mistaking of celiac and stellate sympathetic ganglia for metastatic lymph nodes on multimodal prostate-specific membrane antigen (PSMA)-ligand PET imaging. The aim was to check the intensity of Ga-PSMA-11 uptake and magnetic resonance (MR) features of superior cervical ganglia (SCG) on PET/MR imaging.

METHODS

In 89 patients 106 SCG were reliably identified on Ga-PSMA-11 PET/MR. For each SCG, qualitative assessment (visual subjective avidity, diffusion restriction, shape, and the presence of central hypointensity) and quantitative measurements [dimensions, maximal standardized uptake value (SUVmax), mean apparent diffusion coefficient (ADC)] were performed.

RESULTS

Mean SUVmax in SCG amounted to 1.88 ± 0.63 (range: 0.87-4.42), with considerable metabolic activity (SUVmax ≥ 2) in 37.7% of SCG; mean thickness was 3.18 ± 1.08 mm. In subjective visual evaluation, SCG avidity was classified as mistakable or potentially mistakable with underlying malignancy in 32.1% of cases. Mean ADC values amounted 1749.83 ± 428.83 × 10mm/s. In visual assessment, 74.5% of ganglia showed moderate to high diffusion restriction. An oval or longitudinal shape on transverse MR plane was presented by 59.4% of SCG. The central hypointensity was detected on MR T2-weighted images only in 10.4% of SCG.

CONCLUSION

SCG, similar to other sympathetic ganglia, show Ga-PSMA-11 uptake. SCG avidity may be of significance, especially in view of frequently occurring SCG oval or longitudinal shape, and moderate to high diffusion restriction in visual assessment, potentially suggesting malignancy on transverse MR plane. Diagnostic imaging specialists and clinicians should be aware of the above.

Magnetic resonance imaging features of the superior cervical ganglion and expected changes after radiation therapy to the head and neck in a long-term follow-up

PURPOSE

This study aimed to assess the magnetic resonance (MRI) features of the superior cervical ganglion (SCG) and to track changes to it induced using radiotherapy across a long-term follow-up.

METHODS

In total, 75 patients who underwent radiotherapy for head and neck malignancies and who were studied with MRI were recruited from two centers. MRI was performed before and after radiotherapy, with a median long-term follow-up of 4.5 years. Baseline SCG features were assessed. Changes in axial cross-sectional area, T2-normalized signal, and apparent diffusion coefficient (ADC) (the latter available in about half of the patients) were analyzed. Repeated measures analysis of variance with Bonferroni's correction was used to analyze changes in the aforementioned parameters (significance level 0.05).

RESULTS

Out of a potential 149 SCGs, 136 were visible at baseline MRI. A variable spatial relationship with the internal carotid artery was found. SCGs showed the "black dot" sign in almost all of the patients. ADC was higher in SCGs than in regional lymph nodes. Cross-sectional area, normalized T2, and ADC increased in the period up to 1 year after radiotherapy and then remained stable in subsequent longer-term follow-up.

CONCLUSION

The SCG has unusual features that allow differentiation from the regional lymph nodes. Changes in morphology and signal after radiotherapy must be taken into account by radiologists to avoid misdiagnosis as recurrent nodal disease. Changes induced using radiotherapy are stable in long-term follow-up and are thus likely attributed to other factors (such as Schwann cell hypertrophy/proliferation) rather than edema.

Serial magnetic resonance imaging evaluations of irradiated superior cervical sympathetic ganglia: Not every retropharyngeal enlarging mass is a sign of malignancy

INTRODUCTION

To describe serial changes in irradiated superior cervical sympathetic ganglia (SCSGs) on MRI (magnetic resonance imaging) evaluation in patients with head and neck squamous cell carcinoma (HNSCC) and to find the features differentiating them from the metastatic retropharyngeal lymph nodes.

MATERIALS AND METHODS

This retrospective study evaluated 52 consecutive patients with definitive radiotherapy with/without chemotherapy for pathologically confirmed HNSCC and pre- and postradiation MRI follow-up evaluations. MR images of SCSGs were analyzed including enhancement pattern, margin, and the presence of intraganglionic hypointensity.

RESULTS

MRI evaluations were performed in 36 men and 16 women with HNSCC with an average age of 58 years, range 23-80 years before irradiation (n=52), and at 6 (n=21) and 13-18 (n=52)months follow-up. Mean total radiation dose was 6351±483 cGy (range, 5640-7000 cGy). Intraganglionic hypointensity, homogeneous enhancement pattern, and well-defined margins were observed in 96%, 97%, and 97% of ganglia on the last follow-up, which showed no difference between pretreatment and 6-month follow-up (P>0.05). Mixed linear model analysis revealed significant increases in diameter and normalized T2SI of SCSGs after irradiation (P< 0.05).

CONCLUSIONS

Despite of the increase in diameter and normalized T2SI of SCSGs, preservation of intraganglionic hypointensity, well-defined margins and homogeneous enhancement might be helpful for radiologists to identify SCSGs during the follow-up of HNSCC patients.

MR Imaging of the Superior Cervical Ganglion and Inferior Ganglion of the Vagus Nerve: Structures That Can Mimic Pathologic Retropharyngeal Lymph Nodes

BACKGROUND AND PURPOSE

The superior cervical ganglion and inferior ganglion of the vagus nerve can mimic pathologic retropharyngeal lymph nodes. We studied the cross-sectional anatomy of the superior cervical ganglion and inferior ganglion of the vagus nerve to evaluate how they can be differentiated from the retropharyngeal lymph nodes.

MATERIALS AND METHODS

This retrospective study consists of 2 parts. Cohort 1 concerned the signal intensity of routine neck MR imaging with 2D sequences, apparent diffusion coefficient, and contrast enhancement of the superior cervical ganglion compared with lymph nodes with or without metastasis in 30 patients. Cohort 2 used 3D neurography to assess the morphology and spatial relationships of the superior cervical ganglion, inferior ganglion of the vagus nerve, and the retropharyngeal lymph nodes in 50 other patients.

RESULTS

All superior cervical ganglions had homogeneously greater enhancement and lower signal on diffusion-weighted imaging than lymph nodes. Apparent diffusion coefficient values of the superior cervical ganglion (1.80 ± 0.28 × 10^-3mm²/s) were significantly higher than normal and metastatic lymph nodes (0.86 ± 0.10 × 10^-3mm²/s, P < .001, and 0.73 ± 0.10 × 10^-3mm²/s, P < .001). Ten and 13 of 60 superior cervical ganglions were hypointense on T2-weighted images and had hyperintense spots on both T1- and T2-weighted images, respectively. The latter was considered fat tissue. The largest was the superior cervical ganglion, followed in order by the retropharyngeal lymph node and the inferior ganglion of the vagus nerve (P < .001 to P = .004). The highest at vertebral level was the retropharyngeal lymph nodes, followed, in order, by the inferior ganglion of the vagus nerve and the superior cervical ganglion (P < .001 to P = .001). The retropharyngeal lymph node, superior cervical ganglion, and inferior ganglion of the vagus nerve formed a line from anteromedial to posterolateral.

CONCLUSIONS

The superior cervical ganglion and the inferior ganglion of the vagus nerve can be almost always differentiated from retropharyngeal lymph nodes on MR imaging by evaluating the signal, size, and position.

Metastatic squamous cell carcinoma to the superior cervical ganglion mimicking a retropharyngeal lymph node

BACKGROUND

Metastasis of squamous cell carcinoma (SCC) to the superior cervical ganglion (SCG) has never been reported. Its anatomic location may easily be mistaken for a retropharyngeal lymph node. We present the first case of SCC metastasis to the SCG.

METHODS

We report a case of a 69year-old never smoking male, who presented with right retropharyngeal PETCT-avid disease following chemoradiation for squamous cell carcinoma of the tonsil. He was brought to the operating room for resection, intraoperative radiation and reconstruction.

RESULTS

Intraoperatively, visualization and frozen section confirmed squamous cell carcinoma located in the superior cervical ganglion. The ganglion was resected, intraoperative radiation was given and the patient was reconstructed with a radial forearm free flap. Postoperatively, the patient displayed features of a Horner's syndrome.

CONCLUSIONS

The superior cervical ganglion may be mistaken for a retropharyngeal lymph node. Although extremely rare, these entities may be differentiated on the basis of radiological studies.