Detection and Response Evaluation of Extramedullary and Medullary Blast Crisis in Chronic Myeloid Leukemia on 18F-FDG PET/CT

FDG PET/CT imaging is usually not routinely undertaken in patients of chronic myeloid leukemia (CML). We present a case of CML on tyrosine kinase inhibitor treatment with disease control indicated by BCR-ABL1 quantitative reverse transcription-polymerase chain reaction, who underwent PET/CT for evaluation of recent onset vision deterioration with subretinal exudates on ophthalmological examination. PET CT detected FDG-avid sinonasal thickening and bilateral marrow lesions. These lesions on histopathological sampling, examination revealed extramedullary and intramedullary CML blast crisis. Patient was then treated with steroids and change of tyrosine kinase inhibitor for the CML blast crisis. FDG PET/CT done subsequently was able to demonstrate morphological and metabolic response in the lesions.