Overview
Definition:
Pediatric adrenalectomy for neuroblastoma involves the surgical removal of the adrenal gland or a portion thereof, primarily to resect or debulk a neuroblastoma tumor
Neuroblastoma is a common extracranial solid tumor of childhood arising from neural crest cells, often originating in the adrenal medulla
Surgical intervention is a cornerstone of multimodal therapy, aiming for complete tumor resection for better prognosis.
Epidemiology:
Neuroblastoma accounts for approximately 15% of all pediatric cancer deaths
It most commonly occurs in infants and young children, with a median age of diagnosis around 18 months
The adrenal glands are the most frequent primary site (40-50%), followed by paraspinal ganglia
Incidence varies by ethnicity and geographic region.
Clinical Significance:
Adrenalectomy for neuroblastoma is crucial for tumor staging, providing prognostic information, achieving local control, and reducing the tumor burden, which is critical for improving response to adjuvant therapies like chemotherapy and radiotherapy
Successful resection is a significant determinant of long-term survival.
Clinical Presentation
Symptoms:
Abdominal mass, often palpable and firm
Abdominal pain
Irritability and poor feeding in infants
Systemic symptoms such as fever, weight loss, and hypertension may be present
Horner's syndrome (ptosis, miosis, anhidrosis) if the tumor involves sympathetic ganglia
Bone pain or pathological fractures if there is metastatic disease
Respiratory distress if a large retroperitoneal mass compresses the diaphragm or lungs
Opsoclonus-myoclonus syndrome (dancing eyes, dancing feet) is a paraneoplastic phenomenon.
Signs:
Palpable abdominal or flank mass
Signs of dehydration or cachexia
Hypertension
Pallor due to anemia
Ecchymosis around the eyes (raccoon eyes) or periorbital edema
Distended abdomen
Signs of metastatic disease in lymph nodes, liver, bones, or bone marrow.
Diagnostic Criteria:
Diagnosis is typically based on a combination of clinical findings, elevated serum and urinary catecholamine metabolites (VMA, HVA), characteristic imaging findings (ultrasound, CT, MRI, MIBG scan), and histological confirmation of tumor type with immunohistochemical markers (e.g., synaptophysin, chromogranin) and molecular markers (e.g., MYCN amplification) for risk stratification
Complete resection is defined as no gross residual tumor at the operative site.
Diagnostic Approach
History Taking:
Detailed history focusing on the onset and progression of symptoms
Family history of neuroblastoma or other cancers
Inquiry about fever, weight loss, feeding difficulties, bone pain, or neurological symptoms
Maternal history of gestational hypertension or use of certain medications during pregnancy can be relevant.
Physical Examination:
Thorough general physical examination
Careful palpation of the abdomen to assess the size, consistency, mobility, and tenderness of any mass
Assessment of vital signs, including blood pressure
Examination for signs of metastatic disease (lymphadenopathy, hepatomegaly, bone tenderness, neurological deficits).
Investigations:
Biochemical: Serum and 24-hour urinary catecholamine metabolites (vanillylmandelic acid - VMA, homovanillic acid - HVA)
Imaging: Ultrasound of the abdomen (initial modality for suspected mass)
CT scan of the abdomen and pelvis with contrast (primary modality for tumor assessment, staging, and surgical planning)
MRI of the abdomen and pelvis (superior for assessing relation to adjacent structures and neural invasion)
MIBG (metaiodobenzylguanidine) scan (for detecting primary tumor and metastatic disease, especially bone and soft tissue)
Bone scan (to evaluate skeletal involvement)
Chest X-ray and CT chest (to rule out thoracic primary tumors or metastases)
Bone marrow aspirate and biopsy (for staging).
Differential Diagnosis:
Other abdominal masses in children: Wilms tumor, hepatoblastoma, rhabdomyosarcoma, lymphoma, teratoma, hydronephrosis, neurofibroma, ganglioneuroma, retroperitoneal abscess
Hypertension can be due to other causes like renal artery stenosis or pheochromocytoma.
Management
Initial Management:
Stabilization of the patient if acutely ill
Management of hypertension or other systemic issues
Prompt diagnostic workup to confirm diagnosis and stage the disease
Multidisciplinary team discussion involving pediatric oncologists, surgeons, radiologists, pathologists, and nurses is essential.
Medical Management:
Chemotherapy is the mainstay of systemic treatment, especially for high-risk neuroblastoma or unresectable tumors
The specific chemotherapy regimen is guided by the International Neuroblastoma Staging System (INSS) or International Neuroblastoma Risk Group (INRG) staging
Adjuvant chemotherapy is often used post-operatively for residual or metastatic disease.
Surgical Management:
Indications: Complete or near-complete resection is the primary goal for localized neuroblastoma (Stage 1 and 2, and selected Stage 3)
For Stage 4 neuroblastoma, debulking may be performed to reduce tumor burden and improve response to chemotherapy
For some primary adrenal tumors that are benign but symptomatic, or suspected malignant tumors, adrenalectomy is indicated
Surgical approach: Laparoscopic adrenalectomy is increasingly preferred for smaller, localized tumors due to its minimally invasive nature, leading to faster recovery and reduced morbidity
Open adrenalectomy (e.g., flank or thoracoabdominal incision) is reserved for very large tumors, extensive local invasion, or when laparoscopic approach is not feasible
Careful dissection is crucial to avoid damage to adjacent structures like the kidney, spleen, pancreas, and major vessels (aorta, vena cava)
Intraoperative imaging may be used to confirm complete resection
Techniques: Complete adrenalectomy involves removing the entire adrenal gland
Partial adrenalectomy or tumor debulking may be necessary if the tumor involves vital structures or if preservation of adrenal function is a concern.
Supportive Care:
Pain management
Nutritional support, including enteral or parenteral feeding if necessary
Fluid and electrolyte balance
Management of chemotherapy-related side effects
Psychological support for the child and family
Regular monitoring for complications and recurrence.
Complications
Early Complications:
Hemorrhage (intraoperative or postoperative)
Injury to adjacent organs (kidney, spleen, pancreas, bowel, liver, great vessels)
Pancreatitis
Adrenal insufficiency (if bilateral adrenalectomy or significant damage)
Wound infection
Postoperative ileus
Atelectasis or pneumonia
Deep vein thrombosis (DVT) or pulmonary embolism (PE).
Late Complications:
Adrenal insufficiency (long-term if bilateral or significant unilateral resection)
Growth and developmental delays
Inferior vena cava (IVC) thrombosis
Chronic pain
Recurrence of neuroblastoma
Radiation-induced sequelae if radiotherapy is used
Secondary malignancies
Chronic gastrointestinal issues.
Prevention Strategies:
Meticulous surgical technique with experienced surgical teams
Preoperative imaging and multidisciplinary planning to understand tumor anatomy and relationship to vital structures
Intraoperative monitoring of vital signs and blood loss
Careful ligation of adrenal vessels
Prophylactic antibiotics
Early ambulation and physiotherapy
Use of anticoagulation if indicated
Careful surgical approach selection (laparoscopic vs
open).
Prognosis
Factors Affecting Prognosis:
Age at diagnosis (younger generally better)
Stage of the disease (INSS/INRG staging)
Tumor histology and grade
Presence of MYCN amplification (poor prognostic marker)
Response to initial therapy
Extent of surgical resection (complete resection is a major positive prognostic factor)
Presence of specific genetic markers (e.g., chromosomal aberrations).
Outcomes:
Prognosis is highly variable and depends on risk stratification
For low-risk neuroblastoma, survival rates can exceed 90% with appropriate treatment
High-risk neuroblastoma has a poorer prognosis, with survival rates ranging from 50-70%, although advancements in therapy are improving these figures
Complete surgical resection is a critical factor in achieving long-term remission and survival.
Key Points
Exam Focus:
Neuroblastoma is a tumor of neural crest origin, most commonly found in the adrenal medulla
The MIBG scan is crucial for staging
Complete surgical resection is a primary goal for localized disease and significantly improves prognosis
Laparoscopic adrenalectomy is preferred for smaller tumors
Adrenal insufficiency is a key complication, especially with bilateral resection.
Clinical Pearls:
Always consider neuroblastoma in a child with an abdominal mass and elevated urinary catecholamines
The surgeon must be intimately familiar with the vascular supply of the adrenal gland and its relation to the kidney and pancreas
Consider the possibility of bilateral disease or metastatic spread even with a seemingly localized adrenal mass
Postoperative care should focus on monitoring for complications and evaluating for adrenal insufficiency.
Common Mistakes:
Inadequate preoperative staging, leading to suboptimal surgical planning
Failure to achieve complete tumor resection due to aggressive invasion or overlooking small metastases
Misidentification of adjacent structures, leading to iatrogenic injury
Underestimating the risk of adrenal insufficiency, particularly in bilateral cases, and not initiating timely hormonal replacement
Delaying consultation with pediatric surgical oncology teams for complex cases.