Acquired cyclic haematopoiesis associated with a radiation-induced chromosomal abnormality with clonal, morphologically normal circulating leucocytes

A 62-year-old male with a history of vesical carcinoma treated with pelvic radiotherapy and cystectomy developed intermittent fevers associated with oral ulcers and neutropenia. Serial blood counts revealed cyclic haematopoiesis, with periodic neutropenia, lymphocytopenia, monocytopenia and thrombocytopenia. Bone marrow examination revealed intermittent hypoplasia without myelodysplasia or leukaemia. Marrow karyotype revealed a clonal chromosomal abnormality which included trisomy 8 and absence of the Y chromosome. We also provide evidence of spontaneous differentiation of the clonal marrow cells to mature leucocytes.