Case of the week Details

Large well defined lobulated heterogeneously enhancing soft tissue lesion in the retroperitoneum , situated posterior to the aorta. Extends superiorly up to L2-L3 intervertebral disc space & inferiorly up to L5-S1 intervertebral disc space.

• A. Antero-inferiorly, - Encasing (<270 degree) the infra renal aorta, displacing it anteriorly without infiltration or thrombosis. - Abutment (<180 degree) and displacement of bilateral common iliac arteries and left proximal external iliac artery. - Displacing the small and large bowel loops anteriorly without infiltration.
• B. Antero-inferiorly, - Encasing (<270 degree) the infra renal aorta, displacing it anteriorly without infiltration or thrombosis. - Abutment (<180 degree) and displacement of bilateral common iliac arteries and left proximal external iliac artery. - Displacing the small and large bowel loops anteriorly without infiltration.
• C. Right laterally, -Abutting (<180 degree) the infra renal IVC, causing significant compression and displacement without infiltration or thrombosis. -Near complete encasement with significant compression of distal left proximal common iliac vein.
• D. Posteriorly abutting the anterior surface of L4 and L5 vertebral bodies and adjoining intervertebral disc space, without infiltration or bony erosion or extension into neural foramina.
• E. Third & fourth lumbar arteries course through the lesion bilaterally. Few prominent nodes in left para aortic and aorto caval regions.

Radiological diagnosis : Ganglioneuroma Patient underwent CT guided biopsy followed by surgical excision HPE- Ganglioneuroma (Ki67% - 1% and mature ganglion cells)

• Fully differentiated neuronal tumors that do not contain immature elements and potentially occur anywhere along with the peripheral autonomic ganglion sites
• Children (mean age 7 years),slight female predominance
• Usually asymptomatic

CT

• Well-defined hypodense masses, homogenous.
• Punctate calcifications (33%)
• Slight or moderate progressive enhancement

MR

• T1- hypointense, T2- heterogeneous hyperintense, diffusion restriction

Whorled sign- microscopic interlacing patterns of Schwann cells and collagen fibers within the tumor

Vessel encasement sign- extend along the inter-vessel space and partially or wholly surround major blood vessel

DD

• Neuroblastoma
• Ganglioneuroblastoma
• Schwannoma
• Lymphangioma

Neuroblastoma- more aggressive and occur in younger patients (2 years)

NB and GNB

• Irregularly, unencapsulated lesions and tend to be inhomogeneous
• Invade adjacent organs and adjacent vessels and tend to metastasize to bone, bone marrow, liver, and lymph nodes
• Regional invasion of paraspinal musculature and psoas may occur, and invasion of the neural foramen into the epidural space

Schwannomas

• Majority of neurogenic retroperitoneum neoplasms
• 2nd to 5th decades of life
• Encapsulated masses and extend along the nerve course
• Large schwannomas may present prominent cystic degeneration and calcification
• Target-like appearance - peripheral high-signal intensity and central low-signal intensity, on T2

Retroperitoneal lymphangiomas

• Any age and are common in males
• Unilocular or multilocular thin-walled cysts with no enhancement

Management- surgery

REFERENCES

• Pacella G, Brunese MC, Donnarumma F, Barrassi M, Bellifemine F, Sciaudone G, Vallone G, Guerra G, Sallustio G. Imaging of Ganglioneuroma: A Literature Review and a Case of in an Adolescent Girl. Diagnostics (Basel). 2023 Jun 27;13(13):2190. doi: 10.3390/diagnostics13132190. PMID: 37443583; PMCID: PMC10341194.
• Xiao J, Zhao Z, Li B, Zhang T. Primary Retroperitoneal Ganglioneuroma: A Retrospective Cohort Study. Front Surg. 2021 May 21;8:642451. doi: 10.3389/fsurg.2021.642451. PMID: 34095202; PMCID: PMC8176303.

Dr MADHU KUMAR
Senior Consultant Radiologist
Manipal Hospital, Yeshwanthpur, Bengaluru.

Dr SHIKHA JOSHI
Radiology resident
Manipal Hospital, Yeshwanthpur, Bengaluru.