Case presentation.
A 90-year old gentleman was admitted to our hospital with symptomatic microcytic anemia and a swollen left leg. His pertinent past medical history included atrial fibrillation for which he was anticoagulated with rivaroxaban. His hemoglobin on arrival was 63 g/L with an MCV of 70 fL showing biochemical evidence of iron deficiency. At the same time, his complete blood count (CBC) was notable for marked thrombocytosis (2114 x 109/L) and neutrophil predominant leukocytosis (16.3 x 109/L). Circulating blasts were not flagged. An ultrasound of his lower limbs demonstrated two hematomas within the left calf measuring 10.7 x 4.9 x 1.7 cm and 12.5 x 6.0 x 3.0 cm respectively (Figure, panel A, posterior and medial complex fluid collection (yellow arrows) consistent with a hematoma is seen). As well, imaging evidence of chronic deep vein thromboses in the right and left popliteal veins was present (Figure, panel B, right popliteal vein (red arrow) demonstrating circumferential thickening (yellow arrows) consistent with thrombus formation is shown). Upper and lower endoscopic assessment demonstrated no evidence of bleeding and testing for acquired von Willebrand disease was within normal limits. Given his anemia and hematomas, his anticoagulation was held. He was subsequently treated with packed red cell transfusion and IV iron sucrose infusion. In lieu of the degree of thrombocytosis which was not in keeping with hemorrhage or iron deficiency, in addition to dysplastic features on peripheral blood film review, a bone marrow biopsy was requested and performed. The aspirate showed morphologic evidence of dyserythropoiesis such as normoblasts with irregular nuclear contours, multinucleated precursors and presence of ring sideroblasts (Figure, panels C-D and I x 50 magnification; please see black arrows). Presence of hypogranular/pelgeroid granulocytes and frank micromegakaryocytes provided evidence of multilineage dysplasia (Figure, Panels C-E). Extremely large multinucleated megakaryocytes (so called “staghorn” type) that exhibited loose cellular association in aggregates, were some myeloproliferative features as identified by trephine hematoxylin and eosin (H&E) and cluster of differentiation 61 (CD61; figure, panels F-H x 50 magnification). Further ancillary testing demonstrated a normal male karyotype as well as mutations in genes ASXL1, DNMT3A, SF3B1and JAK2 facilitating the diagnosis of MDS/MPN-RS-T. Upon radiographic stabilization of his hematoma, anticoagulation was reinitiated. At discharge the patient was treated with 500 mg P.O. daily hydroxyurea resulting in reduction in his platelet count to 686 x109/L two weeks post his admission. He remains stable in the community on this same dose of hydroxyurea.
Discussion .