Common Pediatric Diseases and Disorders
This second part covers lymphomas, solid tumors, supportive care, survivorship, and the latest advances in pediatric oncology. Understanding these aspects is crucial for comprehensive cancer care.
🦠 Lymphomas
Hodgkin Lymphoma
Bimodal age distribution with peaks in adolescence/young adults (15-35) and >55 years.
Clinical Presentation
- Painless lymphadenopathy: Cervical/supraclavicular most common
- B symptoms: Fever, night sweats, weight loss (>10% in 6 months)
- Pruritus: Generalized itching
- Alcohol-induced pain: Pain in involved nodes after alcohol consumption
- Mediastinal mass: Common, may cause cough, dyspnea, SVC syndrome
Diagnosis and Staging
- Diagnosis: Excisional lymph node biopsy (preserve architecture)
- Pathology: Reed-Sternberg cells (CD15+, CD30+)
- Staging: Ann Arbor staging system (I-IV with A/B for symptoms)
- Imaging: PET-CT (staging and response assessment)
- Laboratory: CBC, ESR, LDH, albumin
Treatment and Prognosis
- Treatment: Chemotherapy (ABVD most common) ± radiation
- Prognosis: Excellent overall (90-95% cure)
- Late effects: Secondary cancers, cardiovascular disease, infertility
- Special consideration: Minimize radiation in children to reduce late effects
Non-Hodgkin Lymphoma (NHL)
More common than Hodgkin in children with three main subtypes.
Subtypes and Features
- Lymphoblastic lymphoma (30%): T-cell > B-cell, mediastinal mass common
- Burkitt lymphoma (40%): B-cell, abdominal mass, jaw involvement (endemic)
- Large cell lymphoma (20%): B-cell or T-cell, varied presentation
- Anaplastic large cell lymphoma (10%): T-cell, skin, lymph nodes, systemic symptoms
Clinical Presentation
- Rapidly growing masses: Lymph nodes, abdomen, mediastinum
- B symptoms: Fever, night sweats, weight loss
- Abdominal: Pain, distension, obstruction (Burkitt)
- Mediastinal: Cough, dyspnea, SVC syndrome (lymphoblastic)
- High tumor burden: Risk of tumor lysis syndrome
Oncologic Emergencies in NHL
- Tumor Lysis Syndrome: High risk in Burkitt lymphoma
- Superior Vena Cava Syndrome: Mediastinal masses
- Spinal Cord Compression: Back pain, weakness, incontinence
- Bowel Obstruction/Perforation: Abdominal Burkitt lymphoma
Clinical pearl: "NHL can present as an emergency." High index of suspicion needed for rapid diagnosis and management.
Treatment and Prognosis
- Treatment: Intensive, short-course chemotherapy (no radiation)
- CNS prophylaxis: Intrathecal chemotherapy (sanctuary site)
- Prognosis: Excellent overall (80-90% cure)
- Burkitt lymphoma: Highly curable with intensive chemotherapy
🫀 Solid Tumors
Neuroblastoma
The most common extracranial solid tumor in children with peak incidence <2 years.
Pathophysiology and Presentation
- Origin: Neural crest cells (adrenal medulla, sympathetic chain)
- Clinical features: Abdominal mass (70%), bone pain, periorbital ecchymosis ("raccoon eyes")
- Paraneoplastic syndromes: Opsoclonus-myoclonus-ataxia, hypertension, diarrhea
- Metastases: Bone, bone marrow, liver, skin ("blueberry muffin" babies)
Diagnosis and Risk Stratification
- Diagnosis: Biopsy, elevated urine catecholamines (VMA/HVA)
- Prognostic factors: Age (<18 months better), stage, MYCN amplification (poor)
- Histology: Shimada classification (favorable vs unfavorable)
- DNA ploidy: Hyperdiploidy favorable in infants
- Spontaneous regression: Can occur in stage 4S (special)
Stage 4S Neuroblastoma
- Definition: Localized primary (stage 1, 2) with metastases limited to skin, liver, bone marrow (<10%) in infants <12 months
- Clinical: Massive hepatomegaly can cause respiratory compromise
- Prognosis: Excellent with >90% survival, often spontaneous regression
- Treatment: Low-dose chemotherapy only if symptomatic
Clinical pearl: "Stage 4S neuroblastoma has excellent prognosis despite 'metastatic' designation." Often resolves spontaneously.
Treatment and Prognosis
- Low-risk: Surgery only, >95% survival
- Intermediate-risk: Chemotherapy + surgery, >90% survival
- High-risk: Intensive chemotherapy, surgery, radiation, stem cell transplant, immunotherapy, 50% survival
- Immunotherapy: Anti-GD2 antibodies (dinutuximab) improve survival in high-risk
Wilms Tumor (Nephroblastoma)
The most common renal tumor of childhood with peak age 2-3 years.
Clinical Presentation and Associations
- Presentation: Abdominal mass (smooth, unilateral), hematuria, hypertension
- Associations: WAGR syndrome (Wilms, Aniridia, Genitourinary anomalies, Retardation), Beckwith-Wiedemann, Denys-Drash
- Genetics: WT1 gene (chromosome 11p13)
- Bilateral: 5-10% of cases (synchronous or metachronous)
Diagnosis and Staging
- Imaging: Ultrasound first, then CT/MRI abdomen
- Pathology: Favorable histology (90%) vs unfavorable (anaplasia)
- Staging: Surgical (based on extent and resectability)
- Metastases: Lungs most common (85%), liver, rarely bone, brain
Treatment and Prognosis
- Treatment: Surgery (nephrectomy) + chemotherapy ± radiation
- Chemotherapy: Actinomycin D, vincristine (± doxorubicin)
- Prognosis: Excellent overall (90% survival)
- Bilateral disease: Nephron-sparing surgery when possible
- Late effects: Renal insufficiency, secondary malignancies
Rhabdomyosarcoma
The most common soft tissue sarcoma in children with bimodal peaks (2-6 years and adolescence).
Subtypes and Presentation
- Embryonal (70%): Better prognosis, head/neck, genitourinary
- Alveolar (20%): Worse prognosis, extremities, trunk
- Botryoid: Subtype of embryonal, grape-like masses in hollow organs
- Common sites: Head/neck (parameningeal, orbital), genitourinary, extremities
Genetics and Staging
- Genetics: Alveolar has PAX3/7-FOXO1 fusions (poor prognosis)
- Staging: Based on site, size, nodes, metastases + surgical resection
- Risk groups: Low, intermediate, high based on histology, stage, resection
Special Site Considerations
- Orbital: Excellent prognosis (>90%), vision preservation possible
- Parameningeal: Higher risk of meningeal extension, requires radiation
- Bladder/prostate: Organ preservation approaches with chemo + radiation
- Extremities: Higher risk of metastases, may require amputation
Treatment and Prognosis
- Treatment: Surgery + chemotherapy + radiation
- Chemotherapy: VAC (vincristine, actinomycin, cyclophosphamide)
- Prognosis: Varies by risk group (70-90% overall)
- Metastatic: Poor prognosis (<50% survival)
🦴 Bone Tumors
Osteosarcoma
The most common primary bone cancer in children with peak in adolescence (10-20 years).
Clinical Presentation and Risk Factors
- Presentation: Bone pain (worse at night), swelling, pathologic fracture
- Location: Metaphysis of long bones (distal femur, proximal tibia, proximal humerus)
- Risk factors: Rapid growth, radiation exposure, hereditary retinoblastoma, Li-Fraumeni
- Metastases: Lungs (80%), other bones
Diagnosis and Imaging
- X-ray: Classic "sunburst" pattern, Codman triangle (elevated periosteum)
- MRI: Local extent, skip lesions, soft tissue component
- Biopsy: Essential for diagnosis, should be done at sarcoma center
- Staging: CT chest for metastases, bone scan
Treatment Approach
- Neoadjuvant chemotherapy: 8-10 weeks before surgery (methotrexate, doxorubicin, cisplatin)
- Surgery: Limb-salvage (90%) vs amputation
- Pathologic response: >90% necrosis indicates better prognosis
- Adjuvant chemotherapy: Continue after surgery based on response
- Prognosis: 65-70% for localized, 20-30% for metastatic
Ewing Sarcoma
Second most common bone cancer in children with peak 10-20 years.
Pathology and Presentation
- Origin: Neural crest (primitive neuroectodermal tumor)
- Genetics: t(11;22) EWS-FLI1 fusion (90%)
- Location: Diaphysis of long bones, pelvis, ribs, vertebrae
- Presentation: Pain, swelling, fever (can mimic osteomyelitis)
- Metastases: Lungs, bone, bone marrow
Diagnosis and Treatment
- Imaging: X-ray ("onion skin" periosteal reaction), MRI local extent
- Biopsy: Essential, often small round blue cells on histology
- Treatment: Chemotherapy (VAC/IE) + local control (surgery ± radiation)
- Radiation: Used for unresectable tumors or positive margins
- Prognosis: 70-80% localized, <30% metastatic
Clinical pearl: "Ewing sarcoma can present with fever and elevated inflammatory markers, mimicking infection." Consider malignancy in differential for presumed osteomyelitis not responding to antibiotics.
💊 Supportive Care and Side Effects
Managing Treatment Toxicities
Comprehensive supportive care is essential for successful cancer treatment and quality of life.
Common Side Effects
- Myelosuppression: Neutropenia (fever!), anemia, thrombocytopenia
- Mucositis: Painful mouth sores, difficulty eating
- Nausea/vomiting: Acute and delayed, anticipatory
- Infections: Bacterial, viral (HSV, VZV), fungal, PJP prophylaxis
- Nutrition: Weight loss, malnutrition, need for supplementation
Specific Toxicities
- Cardiac: Anthracyclines (doxorubicin) → cardiomyopathy
- Renal: Cisplatin, ifosfamide → renal insufficiency
- Hearing: Platinum agents → high-frequency hearing loss
- Fertility: Alkylating agents → gonadal dysfunction
- Secondary cancers: Especially with radiation, etoposide, alkylators
Fever and Neutropenia
Definition: Single temperature ≥38.3°C or ≥38.0°C for ≥1 hour + ANC <500
Management: Emergency! Blood cultures, broad-spectrum antibiotics, admit
Risk stratification: Low-risk patients may be eligible for outpatient management
Clinical pearl: "Fever + neutropenia = medical emergency." Do not send home without evaluation.
🌟 Survivorship and Late Effects
Life After Cancer
With >80% of childhood cancer survivors living into adulthood, managing late effects is crucial.
Common Late Effects
- Cardiac: Cardiomyopathy (anthracyclines), coronary artery disease (radiation)
- Endocrine: Growth failure, thyroid dysfunction, precocious puberty, infertility
- Neurocognitive: Learning disabilities, especially after cranial radiation
- Secondary cancers: 5-10% risk at 30 years (breast, thyroid, bone, leukemia)
- Psychosocial: PTSD, anxiety, depression, employment/insurance issues
Survivorship Care
- Long-term follow-up: Regular monitoring based on treatment exposures
- Health promotion: Healthy lifestyle, cancer screening, sun protection
- Transition: Pediatric to adult care, education about treatment history
- Psychosocial support: Counseling, support groups, school/work advocacy
- Fertility preservation: Discussion before treatment when possible
Survivorship Care Plans
Every survivor should receive a comprehensive treatment summary and follow-up care plan including:
- Detailed treatment history (chemotherapy doses, radiation fields)
- Potential late effects based on specific exposures
- Recommended screening and monitoring
- Health promotion recommendations
- Psychosocial resources
🔬 Advances and Clinical Pearls
Recent Advances in Pediatric Oncology
Targeted Therapies
- Imatinib: Philadelphia chromosome-positive ALL
- Larotrectinib/entrectinib: NTRK fusions (pan-cancer)
- ALK inhibitors: Inflammatory myofibroblastic tumor, anaplastic large cell lymphoma
- BRAF inhibitors: Hairy cell leukemia, some gliomas
Immunotherapy
- CAR-T cells: CD19-directed for relapsed/refractory ALL, lymphoma
- Blinatumomab: BiTE antibody for relapsed ALL
- Dinutuximab: Anti-GD2 for neuroblastoma
- Immune checkpoint inhibitors: Limited role in pediatrics (few mutations)
Clinical Pearls
- "Think cancer" with unexplained persistent symptoms despite normal initial workup
- Bone pain that awakens child at night is concerning for malignancy
- Unexplained cytopenias should prompt evaluation for leukemia
- Morning headaches + vomiting = brain tumor until proven otherwise
- Fever + neutropenia = medical emergency requiring immediate antibiotics
- Childhood cancer survivors need lifelong monitoring for late effects
The Future of Pediatric Oncology
- Precision medicine: Molecular profiling to guide therapy
- Immunotherapy: Expanding to more cancer types
- Reduced toxicity: Minimizing late effects while maintaining cure
- Psychosocial support: Integrated throughout the cancer journey
- Global health: Improving outcomes in low-resource settings
🔑 High-Yield Summary - Part 2
| Cancer Type | Key Features | Clinical Pearls |
|---|---|---|
| Hodgkin Lymphoma | Reed-Sternberg cells, B symptoms, excellent prognosis | Alcohol-induced pain classic but rare |
| Non-Hodgkin Lymphoma | Rapidly growing masses, high tumor lysis risk | Can present as oncologic emergency |
| Neuroblastoma | Most common extracranial solid tumor, catecholamine secretion | Stage 4S has excellent prognosis despite metastases |
| Wilms Tumor | Most common renal tumor, associated with syndromes | Excellent prognosis (>90% survival) |
| Osteosarcoma | Most common bone cancer, adolescent peak, metaphyseal | Sunburst pattern on X-ray, lung metastases common |
| Ewing Sarcoma | Small round blue cells, t(11;22), diaphyseal | Can mimic infection with fever, elevated markers |
🎯 Key Takeaways - Part 2
- Lymphomas are highly curable but can present as emergencies (tumor lysis, SVC syndrome)
- Neuroblastoma has unique biology with spontaneous regression possible in infants
- Wilms tumor has excellent prognosis and is associated with specific genetic syndromes
- Bone tumors peak in adolescence and require multimodal therapy
- Supportive care is essential for successful treatment and includes managing infections, side effects, and psychosocial needs
- Survivorship care is lifelong due to risk of late effects from treatment
- New targeted therapies and immunotherapies are expanding treatment options
- Clinical suspicion for cancer should remain high with unexplained persistent symptoms
💝 The Journey Continues
Childhood cancer represents one of medicine's greatest challenges and success stories. From <20% survival in the 1960s to >80% today, the progress has been remarkable. Yet each child's journey is unique, requiring not just medical expertise but compassion, family-centered care, and multidisciplinary support.
The future holds promise for even better outcomes with less toxicity through precision medicine, immunotherapy, and continued research. But the foundation remains early recognition, appropriate referral, comprehensive treatment, and lifelong follow-up.
Pediatric Oncology Philosophy: We don't just treat cancer—we care for children and families through one of life's most difficult journeys. The goal is not just survival, but thriving in the years beyond cancer.