Case of the week Details

• A. A large hetero-echoic retroperitoneal mass lesion with internal vascularity associated with multiple enlarged retroperitoneal nodes causing bilateral grade III hydronephrosis.
• B. Large heterogeneously enhancing lobulated retroperitoneal mass lesion causing encasement and anterior displacement of abdominal aorta, inferior vena cava and bilateral renal vessels.
• C. The lesion is reaching up to the anterior abdominal wall and causing displacement of the adjacent bowel loops.
• D. The heterogeneous mass and retroperitoneal lymph nodes are causing compression of bilateral ureters causing upstream grade III hydroureteronephrosis.
• E. Tiny speck of calcification seen within the lesion 

DIAGNOSIS :

• Poorly differentiated Neuroblastoma (Histopathology proven)

DISCUSSION :

Neuroblastoma :

• Neuroblastoma is the most common extracranial solid tumor in children and the most frequent cancer in infants before the age of 5. 
• It arises from neural crest cells that form the sympathetic nervous system, most commonly originating in the adrenal medulla or paraspinal sympathetic ganglia.
• Derived from primitive sympathetic neuroblasts that fail to differentiate properly.
• Can present as a localized or metastatic disease.
• Mostly sporadic, but 1-2% are familial, associated with ALK and PHOX2B mutations.
• Amplification of MYCN oncogene is a poor prognostic factor.
• Infants (<18 months) with localized disease have excellent outcomes.

Clinical features :

Clinical manifestations vary based on the location of the tumor and metastatic spread:

• General Symptoms: Fatigue, weight loss, fever, irritability
• Abdominal Mass: Firm, irregular, non-tender mass (most common in the adrenal gland)
• Metastatic Symptoms:.
  • Bone pain (bone metastases)
  • Proptosis, periorbital ecchymosis ("raccoon eyes")
  • Hepatomegaly (Pepper syndrome)
  • Skin nodules (blueberry muffin rash)
  • Paraneoplastic syndromes (e.g., opsoclonus-myoclonus syndrome)
• Spinal Involvement: If extending into the spinal canal (dumb bell tumor), it can cause spinal cord compression and neurological deficits.
• Hypertension: Due to catecholamine secretion in some cases elevated urinary vanillymandelic acid/ homovanillic acid

Imaging :

• X-ray:
  • Calcifications in the mass (speckled or coarse)
  • Bone metastases (lytic lesions or periosteal reaction)
• Ultrasound:
  • Heterogeneous mass with possible calcifications
  • Useful for initial evaluation in abdominal cases
• CT Scan:
  • Heterogeneous, enhancing mass with necrosis
  • Calcifications (in 80-90% of cases)
  • Local invasion and vascular encasement
• MRI:
  • Better for soft tissue and spinal involvement
  • T2-hyperintense, heterogeneous mass
  • Extension through neural foramina (dumbbell tumor)
• MIBG Scan (Metaiodobenzylguanidine):
  • Highly specific for neuroblastoma
  • Detects primary and metastatic disease
• Bone Scan & PET-CT:
  • Evaluate metastatic spread
  • FDG-PET useful in MIBG-negative cases

References :

• Sharp SE, Gelfand MJ, Shulkin BL. Pediatric neuroblastoma: Diagnosis, staging, and therapy response assessment with 123I-MIBG scintigraphy. Radiographics. 2016 Oct;36(1):258-278. doi: 10.1148/rg.2016150086. 
• Siegel MJ, Bhalla S. Neuroblastoma: Modern imaging tools for diagnosis and staging. Pediatr Radiol. 2020 Feb;50(2):168-181. doi: 10.1007/s00247-019-04521-2.
• McHugh K. Neuroblastoma: Imaging in diagnosis, staging, and follow-up. Am J Roentgenol. 1998 Sep;171(3):995-1001. doi: 10.2214/ajr.171.3.9725314.

Dr Vikhyat Shetty
MBBS, MD, FRCR
Senior Consultant Manipal Hospitals Radiology Group Yeshwantpur

Dr Skanda Prasad Ragi
MBBS, MD
Junior Consultant – MHRG 

Dr S Shreya 
MBBS, MD
Cross section imaging fellow - MHRG