18F-Fluorodeoxyglucose PET/CT-Guided Palliative Radiotherapy Provides Durable Responses to Over a Dozen Sites of Disease in Relapsed Myeloid Sarcoma.

Myeloid sarcoma (MS) is a rare entity, and FDG PET/CT is a useful tool for staging at diagnosis and response assessment. We present a case of a 72-year-old woman diagnosed with multifocal extramedullary MS, using FDG PET/CT to guide palliative radiotherapy to 13 sites of disease over 2 separate relapses with complete and durable local responses and minimal toxicity. This case represents the largest reported burden of disease in MS successfully treated with FDG PET/CT-guided radiotherapy.