Disseminated Tuberculosis Mimicking Metastatic Cancer During Ruxolitinib Therapy for Polycythemia Vera: A Case Report and Literature Review.
Key claim: Ruxolitinib-induced immunosuppression in polycythemia vera can cause disseminated tuberculosis that mimics metastatic cancer, with false-negative interferon-γ release assays and spuriously elevated tumor markers complicating timely diagnosis.
Abstract
BACKGROUND Polycythemia vera (PV) is a myeloproliferative neoplasm (MPN) characterized by erythrocytosis resulting from the clonal overproduction of hematopoietic cells in the bone marrow and is closely associated with mutations in the Janus kinase 2 (JAK2) gene. Ruxolitinib, a selective JAK1/JAK2 inhibitor used to treat MPNs, predisposes patients to opportunistic infections. Herein, we report the case of a patient with PV treated with ruxolitinib who developed disseminated tuberculosis mimicking metastatic cancer. CASE REPORT A 71-year-old woman presented with imaging findings suggestive of metastases, elevated tumor markers, and a negative interferon-γ release assay. The diagnosis was confirmed by bone biopsy and a positive sputum Mycobacterium tuberculosis polymerase chain reaction test. The patient improved with standard 4-drug antituberculous therapy. In a focused review of 35 published cases of tuberculosis occurring during ruxolitinib therapy for MPNs, disseminated disease accounted for 50% of cases, whereas PV was reported in only 3 cases. Ruxolitinib-induced immunosuppression can lead to false-negative interferon-γ release assay results, and several tumor markers, including soluble interleukin-2 receptor, neuron-specific enolase, cancer antigen (CA)125, and CA15-3, are known to be elevated in tuberculosis. CONCLUSIONS Patients with PV treated with ruxolitinib can develop active tuberculosis, including disseminated forms. When tumor markers are elevated and imaging reveals lesions suggestive of metastases, clinicians should include disseminated tuberculosis in the differential diagnosis and pursue histopathological and microbiological investigations to enable timely diagnosis and appropriate treatment.
Why this matters
Ruxolitinib is increasingly used in PV (hydroxyurea-resistant/intolerant disease and across the second-line pipeline), and this report sharpens awareness that JAK1/2-driven immunosuppression in PV can unmask disseminated tuberculosis presenting as pseudo-metastatic disease. The diagnostic traps — false-negative IGRA and elevated tumor markers — are directly relevant to PV natural history surveillance, where progression to MF or transformation is the usual concern but opportunistic infection can mimic malignant evolution. Recognizing this pattern is important for safe long-term JAK inhibitor use in PV.