In a patient with atrial fibrillation on warfarin, prior stroke, asthma, recent tachycardia, right bundle branch block on ECG, elevated BNP, bilateral lower‑extremity deep vein thrombosis, and a CT‑identified wedge‑shaped posterior‑medial right hepatic lobe infarct, what further work‑up is recommended from a hematology/oncology perspective?

Hematology/Oncology Workup for Hepatic Infarct in a Patient with Atrial Fibrillation and DVT

This patient requires urgent evaluation for occult malignancy given the constellation of bilateral DVT, hepatic infarct, and multiple thrombotic events despite therapeutic anticoagulation—this represents a high-risk thrombophilic state that mandates comprehensive cancer screening from a hematology/oncology perspective. 1

Immediate Cancer Screening Workup

The presence of bilateral DVT combined with an unusual thrombotic site (hepatic infarct) in a patient already on warfarin raises significant concern for cancer-associated thrombosis, which occurs in approximately 10% of patients with unprovoked VTE and carries a 4- to 13-fold higher incidence of thrombotic events. 1, 2

Essential Initial Laboratory Testing

• Complete blood count with differential and platelet count - specifically looking for thrombocytosis (platelets ≥350 × 10⁹/L), anemia (hemoglobin <10 g/dL), or leukocytosis (>11 × 10⁹/L), all of which are associated with higher risk of occult malignancy 1, 2

• Comprehensive metabolic panel including liver function tests and kidney function - critical for both cancer screening and anticoagulation management 3, 2

• Coagulation studies - PT/INR, aPTT, and fibrinogen to assess current anticoagulation status and identify potential consumptive coagulopathy 3, 2

Directed Cancer Screening Based on High-Risk Sites

Given the thrombotic pattern, focus screening on malignancies most commonly associated with cancer-associated thrombosis:

• CT chest/abdomen/pelvis with contrast - prioritize evaluation for pancreatic, gastric, lung, and gynecological malignancies, which are the highest-risk cancers for thrombosis 1, 2

• Age-appropriate cancer screening including colonoscopy if not up to date, given the association with gastrointestinal malignancies 1

• Tumor markers - CA 19-9 (pancreatic), CEA (colorectal), CA-125 (ovarian if female), PSA (prostate if male) - though these should be directed by clinical suspicion rather than ordered indiscriminately 1

Thrombophilia Evaluation

While the patient is already anticoagulated, certain testing can still be performed and may guide long-term management:

• Antiphospholipid antibody panel - lupus anticoagulant, anticardiolipin antibodies, anti-beta-2-glycoprotein I antibodies - as these patients require indefinite anticoagulation if positive 4

• Consider genetic thrombophilia testing (Factor V Leiden, prothrombin G20210A mutation) if family history suggests hereditary thrombophilia, though this is lower priority given the cancer concern 4

Critical Management Considerations

Anticoagulation Strategy Modification

• Consider transition from warfarin to LMWH - The NCCN guidelines recommend LMWH as superior to warfarin for cancer-associated thrombosis, with options including dalteparin 200 units/kg SC daily or enoxaparin 1 mg/kg SC every 12 hours 2

• This patient's thrombosis while on therapeutic warfarin (assuming INR was therapeutic) represents treatment failure and strongly suggests either cancer-associated thrombosis or antiphospholipid syndrome, both of which may respond better to LMWH 2

Duration of Anticoagulation

• If cancer is identified, indefinite anticoagulation is recommended given the bilateral DVT, hepatic infarct, and prior stroke 2, 4

• If no cancer is found but thrombophilia is identified, treatment for 12 months minimum with consideration for indefinite therapy is recommended 4

Hepatic Infarct-Specific Considerations

The wedge-shaped hepatic infarct is unusual and warrants specific attention:

• Evaluate for portal/hepatic vein thrombosis on the CT imaging - this may indicate Budd-Chiari syndrome or portal vein thrombosis, both associated with myeloproliferative neoplasms 2

• Consider JAK2 V617F mutation testing if hepatic vein involvement is present, as this screens for polycythemia vera and essential thrombocythemia 1

• Hepatic function monitoring given the infarct - repeat liver function tests in 1-2 weeks to assess for hepatic dysfunction 3

Common Pitfalls to Avoid

• Do not delay cancer screening - the combination of bilateral DVT and unusual site thrombosis (hepatic infarct) while on anticoagulation is a red flag for malignancy 1, 2

• Do not rely solely on D-dimer - this patient has multiple reasons for elevated D-dimer (active thrombosis, atrial fibrillation, recent hospitalization) making it useless for cancer screening 5

• Do not continue warfarin without reassessment - thrombosis while on warfarin suggests either subtherapeutic INR, cancer-associated thrombosis, or antiphospholipid syndrome, all requiring management modification 2

• Do not order exhaustive tumor markers without clinical suspicion - focus on high-yield imaging (CT chest/abdomen/pelvis) and directed testing based on findings 1

Follow-Up Timeline

• Urgent hematology/oncology consultation within 1-2 weeks for comprehensive evaluation and anticoagulation management 2, 1

• CT imaging within 1 week if not already completed as part of current hospitalization 1

• Repeat imaging in 3-6 months if initial cancer screening is negative, as occult malignancies may not be detectable initially 1