The first case of acute myeloid leukaemia/myeloid sarcoma with cytokeratin expression on blasts diagnosed on urine specimen.

Here we describe a rare case of renal myeloid sarcoma, first discovered incidentally on routine urine analysis, which is one of the first of it's kind to be reported. We describe the vanishingly rare phenomenon of renal myeloid sarcoma presenting without haematological manifestation while also highlighting the often inevitable transformative nature of the disease. We also describe the unusual immunohistochemistry findings, in particular the cytokeratin expression, that is not usually typical of such cases. We briefly discuss use of PET-CT for the disease response monitoring. We summarize treatment that has included palbociclib, use of which was previously reported only in small series of patients with AML with KMT2A mutation.