Dual Hematologic Malignancies: A Case of Concurrent Accelerated-Phase Chronic Myeloid Leukemia and Ann Arbor Stage III Follicular Lymphoma

Objectives: To report an extremely rare case of concurrent accelerated-phase chronic myeloid leukemia (CML) and Ann Arbor stage III follicular lymphoma (FL) and to discuss the diagnostic and therapeutic challenges. Material and Methods: We present the case of a 39-year-old male who presented with progressive lymphadenopathy and abdominal discomfort. The diagnostic workup included clinical evaluation, complete blood count, peripheral blood smear, bone marrow aspiration and analysis, BCR-ABL1 transcript quantification by PCR, contrast-enhanced computed tomography (CT), and nasopharyngeal biopsy with immunohistochemistry. Outcomes: The patient was diagnosed with two synchronous hematologic malignancies: accelerated-phase CML, confirmed by the presence of the b3a2 BCR-ABL1 fusion transcript, and Ann Arbor stage III FL, confirmed by a nasopharyngeal biopsy revealing CD99+/Bcl-2+ germinal centers. Initial therapy with imatinib 400 mg/day and allopurinol led to a paradoxical improvement in both CML parameters and lymphoma-related symptoms, an atypical response for FL. The patient’s clinical condition improved, with a reduction in lymphadenopathy and splenomegaly. Conclusions: The co-occurrence of CML and FL presents significant diagnostic and management challenges. This case highlights an unexpected response of FL to a tyrosine kinase inhibitor (TKI) and underscores the importance of a comprehensive diagnostic evaluation when faced with complex clinical and radiological findings. Further investigation into the potential pathobiological interactions between these two malignancies is warranted.