Isochromosome 17q, a Rare Chromosomal Abnormality in a Female Patient with Pancytopenia.

Myelodysplastic syndromes present with a range of cytogenetic abnormalities that are used to guide diagnosis and management of the disease. Herein, we present the case of a 72-year-old female patient who presented with pancytopenia. Peripheral blood showed Hb 9.0 g/dl, neutrophils less than 1800/mm3, and platelets less than 100,000/mm3. Bone marrow showed erythroid hyperplasia, megaloblastic changes, dyserythropoiesis, multinuclearity, nuclear bridges, nuclear budding, atypical mitoses, and ring sideroblasts. Also, CD34 and CD117 as well as myeloperoxidase positive populations were present. On this basis, a diagnosis of myelodysplastic syndrome was rendered. Chromosome studies showed an abnormal female karyotype with an isochromosome 17q as well as deletion 20q in 17 of the 20 metaphase cells examined. The remaining three cells were cytogenetically normal. Molecular cytogenetic studies using a TP53-specific probe showed only one TP53 signal in 87% of the nuclei examined. An i(17q) as a sole cytogenetic aberration is rare among both MDS and myeloid malignancies in general, but is functionally similar to aberrations of 17p that lead to loss of TP53. This case provides further insight into the spectrum of cytogenetic abnormalities present in MDS.