A 59-year-old man presented with persistent abdominal discomfort 12 months after splenectomy for thrombocytopenia to ameliorate progressive myelofibrosis. Physical examination revealed bilateral loin masses. Computed tomography of the abdomen identified perinephric cuffing by soft tissue nodular masses in the perinephric fat (Figure A). Core needle biopsy of the right perinephric fat revealed haematopoietic cells (Figure B).