Suprarenal Mass

Alexander J. Towbin, MD

DIFFERENTIAL DIAGNOSIS

Common

Normal Adrenal Hypertrophy of Neonate
Neuroblastoma

Less Common

Adrenal Hemorrhage
Pulmonary Sequestration
Ganglioneuroma
Ganglioneuroblastoma

Rare but Important

Adrenal Carcinoma
Adrenal Adenoma
Congenital Adrenal Hyperplasia
Pheochromocytoma

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Adrenal masses are usually malignant
DDx for suprarenal mass in fetus or neonate
- Neuroblastoma, adrenal hemorrhage, or pulmonary sequestration

Helpful Clues for Common Diagnoses

Normal Adrenal Hypertrophy of Neonate
- At birth, normal adrenal is 10-20x larger than adult gland relative to body weight
  - ˜ 1/3 size of neonatal kidney
- Consists mostly of cortical tissue
- Gland decreases in size over 1st 2 weeks
- Thick hypoechoic outer layer and echogenic core on US
Neuroblastoma
- Most common solid extracranial malignancy
  - 6-10% of all childhood cancers
  - 15% of pediatric cancer deaths
- 4th most common pediatric malignancy after leukemia, CNS tumors, and lymphoma
- 2nd most common abdominal neoplasm after Wilms tumor
- > 90% of patients diagnosed before age 5
  - Median age at diagnosis is 22 months
  - Peak incidence in 1st year of life (30%)
- Most common malignancy in 1st month of life
  - Almost always adrenal in origin (90%)
  - Metastases to liver, bone marrow, and skin present at diagnosis (50%)
  - Good prognosis: > 90% survival rate
- Can arise anywhere along sympathetic chain
- ˜ 70% originate in retroperitoneum
  - 35% in adrenal medulla
  - 30-35% in extraadrenal paraspinal ganglia
- Mediastinum is 3rd most common location (20%)
- Patients < 1 year have better prognosis
- Abdominal mass is most common presentation
  - Can present with bruising around eyes
  - Paraneoplastic syndromes in ˜ 2%
- 50% have metastases at diagnosis
  - Most common to liver, bone, and bone marrow
  - Hepatic metastases can be diffuse or nodular
- Calcifications present in ˜ 85% of tumors
- I-123 MIBG uptake in 90-95% of patients
- MR is useful to see intraspinal involvement
- Prognosis varies depending on stage
  - Staged by International Neuroblastoma Staging System

Helpful Clues for Less Common Diagnoses

Adrenal Hemorrhage
- Multiple causes, including neonatal asphyxia, perinatal stress, trauma, septicemia, coagulopathies, and Henoch-Schönlein purpura
- Bilateral hemorrhage in 10%
- When unilateral, R > L
- Can be asymptomatic or life-threatening
- US: Initially appears as hyperechoic mass
  - Liquefies by 2-3 days; becomes anechoic
- CT: Usually seen in setting of trauma
  - Associated with ipsilateral abdominal and thoracic injuries
- Can eventually calcify
Pulmonary Sequestration
- Congenital anomaly
- Nonfunctioning pulmonary tissue
  - No connection to tracheobronchial tree
  - Systemic arterial supply
- Intralobar: Sequestered lung adjacent to normal lung
- Extralobar: Sequestered lung with separate pleural covering
  - More common on left side
  - Can be subdiaphragmatic and suprarenal
  - Intraabdominal in 10-15%
  - Associated with congenital heart disease, congenital diaphragmatic hernia, skeletal malformations, and foregut anomalies
Ganglioneuroma
- Well-differentiated, benign form of neuroblastoma
- Neuroblastoma or ganglioneuroblastoma can mature to ganglioneuroma
  - Most common in stage 4S tumors
- Median age at diagnosis is 7 years
- Most common in mediastinum, retroperitoneum, and adrenal gland
Ganglioneuroblastoma
- Intermediate-grade tumor between ganglioneuroma and neuroblastoma
- Seen in similar locations as neuroblastoma
- Has malignant potential

Helpful Clues for Rare Diagnoses

Adrenal Carcinoma
- < 1% of pediatric malignancies
- More common in females
- Usually occurs before age 6
- Most are hormonally active
  - Usually present with virilization in girls and pseudoprecocious puberty in boys
- Associated with hemihypertrophy, brain neoplasms, and hamartomas
- Tumors are usually large at presentation
- Difficult to differentiate from adenoma
  - Helpful criteria include size > 5 cm, invasion of inferior vena cava, and metastases
- Metastasizes to lung, liver, lymph nodes, and inferior vena cava
Adrenal Adenoma
- Rare in children
- 3x less common than adrenal carcinomas
- Most are hormonally active
  - Cushing syndrome most common
- Often have high lipid content and lose signal on out-of-phase MR imaging
Congenital Adrenal Hyperplasia
- Autosomal recessive error of metabolism
- Infants present with salt-wasting
  - Can be virilization of females
- On US, adrenal measures > 20 mm in length or 4 mm in width
- Adrenals may have wrinkled or cerebriform contour
Pheochromocytoma
- 10-20% of pheochromocytomas occur in children
- Presents with sustained hypertension
  - Accounts for ˜ 1% of hypertension in children
- Associated with von Hippel-Lindau, MEN type 2, and neurofibromatosis type 1
- 50-85% arise in adrenal medulla
- Bilateral pheochromocytomas in 18-38%
- Appear extremely hyperintense on T2
- Malignant pheochromocytomas are less common than in adults
  - Metastasize to bone, liver, lymph nodes, and lungs
- I-123 MIBG is sensitive and specific