A 56-year-old male known to have Primary Myelofibrosis (PMF) on ruxolitinib presented with flank pain and high creatinine, MRI abdomen showed features of extramedullary hematopoiesis. Therefore, Extramedullary hematopoiesis should be considered in patient with PMF presenting with deranged renal function.

Hematologic malignancies are becoming more prevalent, manifesting in various clinical scenarios. Chronic myelogenous leukemia (CML) is usually diagnosed on routine complete blood count as it is typically asymptomatic. However, it can cause multiple signs and symptoms. We present a patient with appendicitis revealing CML during his workup for abdominal pain.