Extramedullary hematopoiesis in chronic myelofibrosis encasing the pelvicaliceal system and perirenal spaces: CT findings.

We examined a 46-year-old male patient with idiopathic myelofibrosis diagnosed 28 months earlier. After chemotherapy and irradiation, CT showed nonnodular, soft tissue masses in the renal hilum, pelvicaliceal system, perirenal and periureteral spaces. Ultrasound-guided biopsy showed extramedullary hematopoiesis (EMH). The mass, which caused delayed nephrographic enhancement, without hydroureteronephrosis, was the only site of EMH. We report the CT findings of this uncommon EMH localization. Copyright (c) 2005 S. Karger AG, Basel.