Description: It turns out the old adage from our medical school days, “If you hear hoofbeats, think of horses, not zebras,” was not completely correct! Indeed, the diagnosis of a “rare disease” turns out to be not as rare as we previously thought. The faculty speaking in this important session have focused their entire careers to patient care and cutting-edge research in areas of rare and even ultra-rare hematologic malignancies. The coupling of increasing pathologic technology and diagnostic methods