Myelofibrosis with complex chromosome abnormality in a patient with erythrocytosis due to hemoglobin Rainier and treated with 32P.

A patient with familial erythrocytosis associated with Hemoglobin Rainier, and previously treated with 32P, developed myelofibrosis with a hyperdiploid chromosome clone in the myeloid cells (51,XX,+1,2q-(q33),+6,+9,+11,-19,+20q+,+mar 1.) This transformation from a benign disorder of differentiated erythrocytes to a malignant disorder may have been secondary to radiophosphorus therapy.