An isolated der(1;21)(q10;q10) translocation in a patient with myelodysplastic syndrome: a case report.

Whole-arm translocations are relatively rare among hematological malignancies. There are a few reports on myeloid malignancies harboring der(1;21)(q10;q10). A 65-year-old male was referred to our hospital due to squamous cell carcinoma of the lung. Pembrolizumab monotherapy resulted in progression, and so chemotherapy involving nab-paclitaxel and carboplatin was administered thereafter. The patient developed cytopenia, and his bone marrow exhibited dysplasia. Chromosomal analysis revealed a whole-arm translocation, der(1;21)(q10;q10). Thus, the patient was diagnosed with myelodysplastic syndrome. The der(1;21)(q10;q10) translocation is a rare variant of the der(1;7)(q10;p10) translocation, which is an adverse prognostic factor for myeloid neoplasms. Clarifying the clinical features of myeloid neoplasms in patients with der(1;21)(q10;q10) would facilitate the elucidation of their tumorigenic mechanisms.