A 69-year-old woman with CKD and myelofibrosis was presented to ED with a 2-day history of dyspnea and general weakness. Laboratory Examination hemoglobin levels : 7.2g/dl (reference range : 11.1 -15.0) Hyperkalemia Serum creatinine: 6.7mg/dL (reference range: 0.4 -1.1mg/dl). Ultrasonography indicated hyperechoic structures around both kidneys MRI without contrast administration revealed splenomegaly, a normal appearing liver, ascites, and rim like lesions on both perirenal spaces (Panel A). A biopsy sample from left perirenal lesion was acquired (Panel B).

Identify this abnormality in the perirenal region. *This case is from Docplexus editorial team for educative purpose only. Source: NEJM Stay Connected, the answer will be posted in the next 48h!