SDMRad

 Radiological Findings, Disease course, and Management

 

Ultrasound Abdomen

 

​

 

 

 

 

 

   

 

 

 

                                Colour Doppler US

 

 

 

 

 

 

 

 

 

 

 

Findings

• well-defined, oval hypoechoic mass lesion with internal calcifications approximately measuring 5.4 x 3.2 cm in left paravertebral region

• significant internal vascularity seen within the lesion on color doppler study

• lesion displaces left kidney superiorly

• Rest normal 

Impression

Left paravertebral mass lesion as described above, likely neoplastic mass

​

CT

NCCT

 

               

                                                  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 CECT

            Arterial phase                              Venous phase

 

 

 

 

 

 

 

 

 

        

                                                               Delayed phase  

 

 

 

 

 

 

 

 

 

 

 

 

 

Findings

• A well-defined intra-abdominal homogeneous soft tissue density lesion noted, located in the left paravertebral region at L2 to L4 level, measuring 4.1 x 4.3 x 57 cm in (AP x ML x CC)   

• It shows few internal nodular calcifications and significant post contrast enhancement. Few internal non-enhancing necrotic areas noted.

• Postero-medially, it abuts left psoas muscle with compressed fat planes and posterolaterally, it causes compression over lower pole of left kidney and left upper ureter.

• Anteriorly, it displaces the adjacent bowel loops and medially, the fat planes with abdominal aorta are maintained.

• Superiorly, it mildly elevates left renal vein.

• Rest normal

Impression

• Features could represent extra-adrenal paraganglioma.

• Suggested hisotophalogical correlation

Disease Course and management

Excision biopsy performed

Histopathological Diagnosis

Ganglioneuroblastoma (Schwannian stroma rich)

 

Discussion

   Background

• Ganglioneuromas and ganglioneuroblastomas are tumors of the sympathetic nervous system that originate from neural crest sympathogonia, which are completely undifferentiated cells of the sympathetic nervous system. Along with neuroblastomas, ganglioneuromas and ganglioneuroblastomas are collectively known as neuroblastic or neurogenic tumors. 

• Most frequently occurring in the abdomen, these tumors can grow wherever sympathetic nervous tissue is found. Common locations for ganglioneuromas and ganglioneuroblastomas include the adrenal gland, paraspinal retroperitoneum (sympathetic ganglia), posterior mediastinum, head, and neck; 

 Diagnosis

 Imaging findings:

 Radiography

• typically discovered on a routine radiograph

• all neuroblastic tumors (ie, ganglioneuroblastomas, ganglioneuromas, and neuroblastomas) look similar. The main difference is that ganglioneuroblastomas and neuroblastomas can possibility metastasize

• variable radiologic appearances and growth behaviors that are reflective of their variable locations.

• Conventional radiographs show a retroperitoneal, posterior mediastinal, pelvis, or neck mass

• Up to 30% of these tumors may show calcifications

• Rib and vertebral foraminal erosions, increased intercostal spaces, and vertebral body pedicle erosions may be seen with both retroperitoneal and posterior mediastinal tumors

• Hepatomegaly, periostitis, widened cranial sutures, focal bone lucencies, focal bone sclerosis, and lucent submetaphyseal zones may indicate metastatic disease

 

Ultrasonography

Ganglioneuromas

• homogeneous, hypoechoic, well-circumscribed mass

Ganglioneuroblastomas

• heterogeneic echogenicity, with areas of hemorrhage and necrosis appearing anechogeneic

• Calcifications appear as either focal or diffuse areas of increased echogenicity with variable appearance of shadowing.

Ultrasonography is useful in evaluating other organs for metastasis and for determining blood flow in blood vessels surrounded by tumor

 

Computed Tomography

• commonly used imaging modality used to evaluate neuroblastic tumors

• superior imaging technique to identify tumor size, organ of origin, tissue invasion, vascular encasement, adenopathy, and calcifications. 

Ganglioneuromas

• Retroperitoneal and adrenal ganglioneuromas appear well-defined

• Their shape ranges from round to lobulated, show discrete and punctate calcifications in 42-60% of cases, and tend to grow around major blood vessels. Ganglioneuromas do not compress these blood vessels, and blood flow remains normal

• Nonenhanced CT scans reveal a homogeneous mass with less attenuation than muscle with delayed heterogeneous uptake of contrast.The reason for this type of uptake is that these tumors take longer to accumulate contrast material in the extracellular space. This delay is directly proportional to the amount of myxoid stroma in the tumor.

 

Ganglioneuroblastomas

• variable appearance can be cystic or solid 

• Abdominal and pelvic tumors are mostly heterogeneous and large; smaller tumors may appear homogeneous

• Areas of bleeding and necrosis may be as large as 4 cm and appear to be of lower attenuation 

• can grow around blood vessels but rarely invade them.

• Vessel compression, can occur,if compression of renal vasculature occurs, hypertension can result. Other vessels at risk include the splenic vein, inferior vena cava, aorta, celiac artery, and superior mesenteric artery (SMA).

• liver or lung metastasis and adenopathy can also be identified.

    Liver metastases appear as diffuse infiltration (in infants) and as focal     areas of low enhancement.

    Metastatic disease of the lung can appear either as well-defined             nodules or as larger areas of tissue consolidation.

    Brain metastases have a variable appearance, ranging from hemorrhagic     to cystic with rim-enhancement to a solid mass.

• Intracranial dural involvement is a more common occurrence and can be seen as meningeal masses and meningeal enhancement. 

 

Magnetic Resonance Imaging

• MRI effective at evaluating organs of origin, regional invasion, and intraspinal tumoral extension.

• MRI done to evaluate possible tumoral invasion of the epidural space and can demonstrate spinal cord and nerve root displacement as well as superior and inferior tumor growth

• also useful in imaging bone marrow; the lesions appear hypointense on T1-weighted images and hyperintense on T2-weighted images 

• can be used to detect hepatic metastases in infants with stage 4S disease, which can be missed on CT scanning because of its appearance as a uniform increase in liver attenuation. These lesions appear hyperintense on T2-weighted MRIs

Ganglioneuromas

• homogeneous on MRIs with relatively intermediate signal intensity on all sequences

• Tumors with intermediate to high signal intensity on T2-weighted images have a higher degree of cellularity ,more collagen and small myxoid component

• Markedly-high T2 intensity, signifies a high myxoid stroma component and low cellularity and collagen amounts

• characteristic curvilinear bands of low signal-intensity on T2-weighted images that impart a whorled pattern to the tumor.

• capsule surrounding the tumor appears as a low-density ring on both T1- and T2-weighted images.

• Early contrast enhancement occurs in areas of relatively high vascularity with high capillary permeability,fibrous tissues show slow or late enhancement

Ganglioneuroblastomas

• heterogeneous with variable enhancement and low signal-intensity on T1-weighted images and high signal-intensity on T2-weighted images

• Tumor calcifications appear as signal voids

• Areas of hemorrhage have a high T1 signal-intensity and cystic areas have a high T2 signal-intensity

• have an enhancing pattern of early enhancement followed by a partial washout; early enhancement is indicative of high vascularity

 

Differential diagnosis

• neuroblastoma, adrenal adenoma, adrenal carcinoma, neurofibroma, schwannoma, and pheochromocytoma.

• Ganglioneuromas can be differentiated from more aggressive neuroblastomas and ganglioneuroblastomas by their regular contours and lack of tissue invasion and vessel encasing, their occurrence in older patients, and their discrete, punctate calcifications on CT scans 

• Neuroblastomas and ganglioneuroblastomas tend to have amorphous or coarse calcifications.

• Ganglioneuromas rarely metastasize, whereas neuroblastomas and ganglioneuroblastomas can metastasize to bone, skin, and other organs

 

Treatment and prognosis

• Low-risk tumors are treated with surgery only

    in case of recurrence, chemotherapy and additional surgery may be         performed

• Intermediate-risk tumors are surgically removed and then treated with chemotherapy

• High-risk tumors are more aggressive.Treatment consists of surgery and chemotherapy, with bone marrow transplantation in some cases 

• Even with aggressive treatment, the 3-year event-free survival rate for these patients is less than 15% (14). Improved 2-year survival after bone marrow transplantation has been documented in some studies

• Children with low- or intermediate-risk tumors have a relatively good prognosis

 

Conclusion

• The neuroblastic tumors NB, GNB, and GN are a spectrum of sympathetic tissue tumors ranging from the very immature and malignant NB to the mature and benign GN

• variance in biologic behavior of NB, GNB, and GN indicates that many factors influence the prognosis for a patient with a neuroblastic tumor 

• Although GN tends to be a more homogeneous tumor than NB or GNB, it is not possible at imaging evaluation to discriminate among these three tumors.

 

References

• Imaging in Ganglioneuroma and Ganglioneuroblastoma. (2017, March 30). from http://emedicine.medscape.com/article /340723-overview

• From the Archives of the AFIP. (n.d.). from http://pubs.rsna.org/doi /full/10.1148/radiographics.22.4.g02jl15911