Diabetes Insipidus as an Initial Presentation of Myelodysplastic Syndrome: Diagnosis with Single-Nucleotide Polymorphism Array-Based Karyotyping.

Myelodysplastic syndrome (MDS) is a group of clonal hematopoietic diseases characterized by cytopenia, dysplasia and increased risk of development to acute myeloid leukemia (AML). Unfavorable cytogenetic changes such as complex karyotypes or chromosome 7 anomalies are predictive of the progression to AML and poor prognosis. Central diabetes insipidus (CDI) is the result of a deficiency of arginine vasopressin, and its major causes are idiopathic, primary or secondary tumors, neurosurgery and trauma. Importantly, CDI is a rare complication of MDS. To date, only 5 cases of MDS co-occurring with CDI have been reported; 3 of 5 had cytogenetic abnormalities uncovered by metaphase cytogenetics and 3 of 5 evolved to AML. Here, we describe a 74-year-old woman who presented with CDI as her initial symptom of MDS and eventually progressed to AML. The metaphase cytogenetics, combined with the single-nucleotide polymorphism array (SNP-A)-based karyotyping, with superiority in resolution and detecting copy number variation, revealed a complex karyotype that included monosomy of chromosome 7, deletion of 20q, and absence of heterogeneity (AOH) in more than one chromosome. To the best of our knowledge, this is the first case report of MDS co-occurring with CDI with numerous cytogenetic abnormalities revealed by the SNP-A-based karyotyping. Our case supports that the cytogenetic abnormalities may be associated with the clinical features and the prognosis of MDS co-occurring with CDI. The SNP-A-based karyotyping is helpful in revealing more subtle cytogenetic abnormalities and unveiling their roles in the pathogenesis of MDS.