Pediatric Solid Tumors: Lymphoma, Neuroblastoma, Wilms, Sarcomas

Non-Hodgkin lymphoma (Burkitt, lymphoblastic, large cell) · Hodgkin disease · Neuroblastoma (staging, MYCN) · Wilms tumor (nephroblastoma, WT1) · Mesoblastic nephroma · Soft tissue sarcomas · Rhabdomyosarcoma (alveolar, embryonal)
🧬 Key concepts: NHL often aggressive (Burkitt abdominal, lymphoblastic mediastinal). Hodgkin: Reed-Sternberg cells, excellent survival. Neuroblastoma: catecholamines, MYCN amplification poor prognosis. Wilms: favorable histology, surgery + chemotherapy. Rhabdomyosarcoma: PAX-FOXO1 fusion in alveolar subtype.

📖 Lymphoma, neuroblastoma, Wilms, rhabdomyosarcoma

🩸 Non-Hodgkin lymphoma (NHL)
Burkitt (sporadic/endemic, MYC t(8;14)), lymphoblastic (T-cell, mediastinal), large cell (ALCL, anaplastic). Staging: Murphy. High cure rate with intensive chemotherapy.
🧬 Hodgkin lymphoma
Bimodal (adolescents). Reed-Sternberg cells (CD15+, CD30+). Nodular sclerosis most common. PET/CT staging. Chemotherapy + involved-field RT, excellent survival >90%.
🧫 Neuroblastoma
Sympathetic chain tumor; abdomen (adrenal), thorax, neck. Urine HVA/VMA. MYCN amplification (poor). Low-risk: observation/surgery; high-risk: multimodality (chemo, surgery, HDCT/HSCT, anti-GD2).
🩺 Wilms tumor (nephroblastoma)
Most common renal tumor in children. Associated syndromes: WAGR, Beckwith-Wiedemann, Denys-Drash. Favorable histology (triphasic). Surgery + chemotherapy (vincristine, dactinomycin, doxorubicin).
💪 Soft tissue sarcomas (Rhabdomyosarcoma)
Embryonal (orbit, head/neck, genitourinary) – favorable. Alveolar (extremities, trunk) – PAX-FOXO1 fusion, worse prognosis. Chemotherapy (VAC: vincristine, actinomycin, cyclophosphamide) + local control.
⚠️ Red flags: Painless lymphadenopathy (>2cm, supraclavicular, persistent), B symptoms (fever, night sweats, weight loss), abdominal mass (Wilms, neuroblastoma), proptosis (neuroblastoma), scrotal mass (rhabdomyosarcoma).

🩺 Clinical approach to pediatric solid tumors

1
Lymphadenopathy – when to suspect lymphoma? – Supraclavicular, >2cm, persistent >4 weeks, firm, matted, associated with B symptoms, mediastinal mass (T-NHL). Excisional biopsy preferred.
2
Abdominal mass differential – Wilms: unilateral, smooth, rarely crosses midline, hypertension (renin). Neuroblastoma: irregular, calcification, crosses midline, opsoclonus-myoclonus. Imaging: ultrasound, CT/MRI.
3
Neuroblastoma staging and markers – INRG staging (image-defined risk factors). Urinary HVA/VMA, MIBG scan. MYCN amplification (poor), ploidy (hyperdiploid good in infants).
4
Wilms tumor workup – CT abdomen (bilateral? intravascular extension?). Avoid biopsy if typical (risk of rupture). Staging (I-V). Histology (favorable vs anaplastic).
5
Rhabdomyosarcoma evaluation – Site (orbit, parameningeal, bladder, extremity). Imaging (MRI), biopsy for histology (embryonal vs alveolar) and fusion status (PAX3/7-FOXO1).
📌 Clinical pearl: Opsoclonus-myoclonus-ataxia syndrome is a paraneoplastic presentation of neuroblastoma (often low stage, favorable prognosis). Immediate tumor search.

📋 Stepwise management: lymphoma, neuroblastoma, Wilms, RMS

1
Hodgkin lymphoma – ABVD or OEPA/COPDAC (pediatric regimens). Avoid RT in low-risk. PET/CT for response assessment. Late effects: secondary breast cancer (chest RT), hypothyroidism.
2
Non-Hodgkin lymphoma (Burkitt, lymphoblastic) – Intensive short-course chemotherapy (CODOX-M/IVAC, LMB protocol). CNS prophylaxis. Tumor lysis risk (rasburicase). Cure >85%.
3
Neuroblastoma (high-risk) – Induction (COG: cisplatin, etoposide, cyclophosphamide, doxorubicin) → surgery → high-dose chemotherapy + autologous stem cell rescue → anti-GD2 antibody (dinutuximab) + isotretinoin.
4
Wilms tumor (stage I-II, favorable histology) – Nephrectomy + vincristine + dactinomycin (4-6 months). Stage III/IV: add doxorubicin ± radiotherapy. Bilateral Wilms: neoadjuvant chemotherapy.
5
Rhabdomyosarcoma – Chemotherapy (VAC or IVA). Local control (surgery if feasible; radiotherapy). Embryonal (orbit) excellent prognosis; alveolar (fusion-positive) worse, treat intensively.
🚨 Emergency in NHL: Tumor lysis syndrome (Burkitt) – hydration, rasburicase, monitor electrolytes. Superior vena cava syndrome (T-NHL) – steroids, avoid anesthesia.

🧠 Reflex prompts: lymphoma, neuroblastoma, Wilms, RMS

🩸 8-year-old with painless cervical lymphadenopathy, fever, night sweats, weight loss. Biopsy shows Reed-Sternberg cells. Diagnosis?
Hodgkin lymphoma (nodular sclerosis). PET/CT staging. ABVD chemotherapy.
🧬 4-year-old with abdominal distension, fever, and 'apple core' lesion on imaging. LDH 2000. Diagnosis?
Burkitt lymphoma (sporadic). Urgent TLS prophylaxis. CODOX-M/IVAC chemotherapy.
🧫 18-month-old with abdominal mass, opsoclonus-myoclonus. Urine HVA/VMA elevated. Likely?
Neuroblastoma (low-stage often). Favorable prognosis. Resection +/- observation.
🩺 3-year-old with asymptomatic abdominal mass. CT shows large intrarenal mass, no calcification. Likely?
Wilms tumor (nephroblastoma). Nephrectomy + vincristine/dactinomycin.
💪 7-year-old with painless scrotal mass. Biopsy shows small blue cells with alveolar pattern and PAX3-FOXO1 fusion. Diagnosis?
Alveolar rhabdomyosarcoma. VAC chemotherapy + local therapy.
🧬 Which genetic syndrome predisposes to Wilms tumor and aniridia?
WAGR syndrome (11p13 deletion: WT1 + PAX6).
🧫 What is the most important prognostic factor in neuroblastoma?
MYCN amplification status (poor if amplified). Also age, stage, ploidy.
🩺 What is the classic staging system for pediatric NHL?
St. Jude/Murphy staging (I-IV, includes marrow/CNS).
🧬 Which translocation is characteristic of Burkitt lymphoma?
t(8;14)(q24;q32) – MYC/IgH.
💊 What is the primary chemotherapy regimen for high-risk neuroblastoma (induction)?
COG: cyclophosphamide, cisplatin, etoposide, doxorubicin (or N7 regimen).