HK2 and Miyoshi myopathy: Although the vast majority of functional PET imaging studies is performed with 18F-FDG, this tracer carries some serious limitations in MM imaging: it demonstrates a false negativity incidence of approximately 11% which is associated with low hexokinase-2 expression in some MM patients, and it shows lower sensitivity than MRI in diffuse bone marrow infiltration, leading potentially to patient misclassifications if used as the only functional imaging technology [1, 8].