Initial Workup for Suspected Hematologic Malignancy
The initial workup requires a systematic approach combining clinical assessment, laboratory evaluation, bone marrow examination, and comprehensive ancillary testing including immunophenotyping, cytogenetics, and molecular studies to establish diagnosis, classification, and risk stratification. 1
Clinical Assessment and History
Obtain detailed clinical information that must be readily accessible to the pathologist:
- Demographics: Age, sex, and ethnicity (ethnicity is prognostically significant—Hispanics have worse outcomes in acute lymphoblastic leukemia) 1
- Medical history: Any prior hematologic disorders, known predisposing conditions or syndromes, previous malignancies 1
- Treatment history: Prior cytotoxic therapy, immunotherapy, or radiotherapy (therapy-related AML accounts for 5-20% of cases) 1
- Exposure history: Document environmental/occupational exposures to benzene, formaldehyde, butadiene, or ionizing radiation 1
- Confounding factors: Recent growth factor therapy, transfusions, or medications that may obscure features of acute leukemia 1
- Family history: Hematologic disorders, other malignancies, or germline predisposing syndromes 1
Physical Examination
Document specific findings:
- Organomegaly (hepatosplenomegaly) 1
- Lymphadenopathy 1
- Cutaneous lesions (leukemia cutis) 1
- Neurologic abnormalities 1
- Presence of tumor masses (particularly mediastinal) 1
Laboratory Studies
Initial blood work must include:
- Complete blood count with differential and peripheral blood smear review (mandatory for all patients) 1
- Comprehensive metabolic panel 1
- Lactate dehydrogenase (prognostic relevance and tumor lysis syndrome marker) 1
- Uric acid and phosphate levels (tumor lysis syndrome assessment, particularly important in B-lymphoblastic lymphoma) 1
- Coagulation panel: Prothrombin time, partial thromboplastin time, and fibrinogen (essential to detect disseminated intravascular coagulation in acute promyelocytic leukemia) 1
Bone Marrow Examination
Fresh bone marrow aspirate is required for all patients suspected of acute leukemia:
- Bone marrow aspirate smears for morphologic evaluation 1
- Bone marrow trephine core biopsy with touch preparations 1
- Marrow clots if available 1
If bone marrow aspirate is inadequate or contraindicated: Peripheral blood may be used for diagnosis and ancillary studies if sufficient blasts are present; touch imprint preparations of core biopsy should be prepared 1
Required Ancillary Testing
The following tests must be performed on all patients:
Immunophenotyping
- Multicolor flow cytometry (8-10 colors) on bone marrow aspirate or peripheral blood to distinguish acute myeloid leukemia, B-lymphoblastic leukemia, T-lymphoblastic leukemia, and acute leukemia of ambiguous lineage 1
- If flow cytometry cannot be performed, immunohistochemical studies may be used as an alternative 1
Cytogenetic Analysis
- Conventional karyotyping (mandatory—cannot be replaced by FISH or molecular testing alone) 1
- FISH studies based on suspected subtype 1:
Molecular Genetic Testing
Essential molecular markers for risk stratification and targeted therapy:
- FLT3-ITD and FLT3-TKD (results should be available rapidly to allow addition of FLT3 inhibitor by day 8 of chemotherapy) 1
- NPM1, CEBPA (prognostic markers) 1
- IDH1, IDH2 (prognostic and therapeutic targets) 1
- RUNX1, ASXL1, TP53 (prognostic markers) 1
- KIT (when core-binding factor AML is diagnosed) 1
- For acute lymphoblastic leukemia: BCR-ABL1 fusion, PAX-5, JAK1, JAK2, IKZF1 for B-ALL; NOTCH1, FBXW7 for T-ALL 1
Multiplex gene panels and next-generation sequencing should be obtained for comprehensive prognostic assessment 1
Cerebrospinal Fluid Evaluation
- Mandatory for all acute lymphoblastic leukemia patients receiving intrathecal therapy: Obtain CSF with cell count, cytocentrifuge preparation, and blast enumeration by pathologist 1
- For other acute leukemias: CSF examination when clinically indicated and no contraindication exists 1
- Flow cytometry may be performed on CSF 1
Imaging Studies
- CT scan of chest, abdomen, and pelvis to determine if disease is localized or disseminated 1
- PET/CT if extramedullary disease is suspected 1
- CNS imaging (CT or MRI) if significant neurologic signs or symptoms present to detect intracranial bleeding, leptomeningeal disease, or mass lesions 1
Specimen Handling and Testing Location
Critical considerations:
- If molecular testing is not available at the treatment center, evaluation at an outside reference laboratory or transfer to another institution is recommended prior to performing marrow evaluation 1
- Cryopreserved cells or nucleic acid should be stored for future molecular/genetic studies in a laboratory compliant with regulatory requirements 1
- Central workup should be performed in a cancer center or university-based hospital when possible 1
Reporting Timeline
Preliminary report with basic diagnostics (cytomorphology and flow cytometry) should be available within 48-72 hours 1
Complete final comprehensive report including all risk factors should be issued within 1-2 weeks when all ancillary test results are available 1
Common Pitfalls to Avoid
- Do not rely solely on FISH or molecular testing—conventional karyotyping is mandatory 1
- Do not delay FLT3 testing—results must be available rapidly for treatment decisions 1
- Do not perform bone marrow biopsy of extramedullary tumor if complete panel of ancillary studies has been performed on positive peripheral blood or bone marrow sample 1
- Do not use potassium citrate or other non-chloride potassium salts in patients requiring supplementation, as these can worsen metabolic complications 2
- Ensure adequate sample collection and preservation for molecular studies at initial diagnosis—inadequate samples cannot be repeated once treatment begins 1