Calcium Pyrophosphate Crystal Inflammatory Arthritis (Pseudogout) with Myelodysplastic Syndrome: A New Paraneoplastic Syndrome?

To the Editor: Calcium pyrophosphate (CPP) deposition in articular tissue causes a spectrum of clinical presentations including asymptomatic chondrocalcinosis, acute CPP crystal arthritis (pseudogout), and chronic CPP inflammatory arthritis1. Known risk factors include older age, osteoarthritis, prior joint injury, metabolic disease, and rarely, family history2. Myelodysplastic syndromes (MDS) are a clinically and genetically heterogeneous group of stem cell disorders generally characterized by hypercellular bone marrow and peripheral cytopenias3. Prognosis depends on comorbidities and disease factors including number of cytopenias, specific chromosomal abnormalities, and degree of marrow blast infiltration [5%–9%, 10%–19%, and ≥ 20% represent refractory anemia with excess blasts (RAEB)-1, RAEB-2, and acute myeloid leukemia (AML), respectively]4. The patient died before our case report was prepared, and thus we were not able to obtain his written consent to publish the material; however, while he was alive we discussed our plan to prepare this case report and he was in agreement. Our patient was a 75-year-old man who developed dyspnea in October 2015. Anemia and leukopenia were noted, and bone marrow biopsy revealed hypercellular marrow with 10% blasts consistent with RAEB-2. A very complex/monosomal karyotype including loss of chromosome 17 was noted. … Address correspondence to Dr. S.K. Tedeschi, Brigham and Women’s Hospital, Division of Rheumatology, 75 Francis St., Boston, Massachusetts 02115, USA. E-mail: stedeschi1{at}bwh.harvard.edu