AML & Auer Rods
Adults; myeloblasts with Auer rods (myeloperoxidase+); t(15;17) Acute Promyelocytic Leukemia (APL) treated emergently with ATRA.
CML & Philadelphia
t(9;22) BCR-ABL tyrosine kinase fusion; low Leukocyte Alkaline Phosphatase (LAP) score; first-line therapy: Imatinib.
CLL & Smudge Cells
Elderly; CD5+ CD20+ B-cells; fragile 'smudge cells' on smear; asymptomatic patients managed with watchful waiting.
Hodgkin Lymphoma
Reed-Sternberg cells (CD15+, CD30+ 'owl eyes'); bimodal age distribution; localized nodal spread; B-symptoms (fever, night sweats, weight loss).
The Four Classic Leukemias: High-Yield Board Comparison
| Leukemia | Classic Demographics | Smear & Cytochemistry | Key Genetics & Treatment |
|---|---|---|---|
| AML | Older adults (median 65 yrs) | Myeloblasts > 20%, Auer rods, Myeloperoxidase (MPO) positive | t(15;17) PML-RARA in APL (treat immediately with All-Trans Retinoic Acid / Arsenic Trioxide) |
| ALL | Children (peak 2-5 yrs) | Lymphoblasts > 20%, PAS positive, TdT positive | t(12;21) good prognosis; t(9;22) poor prognosis; mandatory CNS prophylaxis (intrathecal methotrexate) |
| CML | Middle-aged adults (45-65 yrs) | Full spectrum of myeloid precursors (basophils, myelocytes); Low LAP score | t(9;22) Philadelphia chromosome (BCR-ABL1 fusion tyrosine kinase); treat with Imatinib / Dasatinib |
| CLL | Elderly (> 65 yrs) | Mature-appearing small lymphocytes, Smudge cells / basket cells | Co-express CD5 and CD19/CD20; complication: Autoimmune hemolytic anemia (AIHA) or Richter transformation to DLBCL |
Tumor Lysis Syndrome (TLS) Prevention & Management
TLS is an oncologic emergency triggered by massive lysis of malignant cells following chemotherapy initiation (especially Burkitt lymphoma and ALL):
Classic Metabolic Tetrad
- Hyperkalemia: Risk of fatal ventricular arrhythmias
- Hyperphosphatemia: Binds serum calcium
- Hypocalcemia: Tetany, seizures, QT prolongation
- Hyperuricemia: Urate nephropathy & acute renal failure
Prophylaxis Protocol
- IV Hydration: Aggressive pre-chemotherapy saline
- Allopurinol: Xanthine oxidase inhibitor (blocks new uric acid synthesis)
- Rasburicase: Recombinant urate oxidase (breaks uric acid down into soluble allantoin; contraindicated in G6PD)
OMM Board Correlate: Lymphatic System & Oncologic Safety
- Absolute Contraindication: Direct lymphatic pump techniques (thoracic pump, splenic pump, pedal pump) are absolutely contraindicated in patients with acute leukemia or active lymphoma due to the risk of accelerating dissemination of malignant cells.
- Gentle Myofascial Release: Gentle indirect myofascial release of the thoracic inlet and suboccipital release are safe for palliative pain management.
- Bone Fragility: Severe osteopenia and marrow infiltration preclude any HVLA thrusts across all spinal and pelvic regions.
Board Traps & Common Distractors
- Acute Promyelocytic Leukemia (APL) can trigger catastrophic Disseminated Intravascular Coagulation (DIC); if APL is suspected, start All-Trans Retinoic Acid (ATRA) immediately before waiting for bone marrow or cytogenetic results.
- Rasburicase is strictly contraindicated in patients with G6PD deficiency because its enzymatic reaction produces hydrogen peroxide, triggering massive acute hemolysis.
- A patient with CLL who develops sudden fever, weight loss, and rapidly expanding localized lymphadenopathy has likely undergone Richter transformation into aggressive Diffuse Large B-Cell Lymphoma (DLBCL).