[Fat necrosis mimicking recurrent kidney cancer]

Fat necrosis is a benign inflammation of adipose tissue, which is associated with sterile saponification, due to impaired blood supply. At the same time, differential diagnostics with malignant neoplasms and tumor relapses is extremely difficult due to the similar features according to imaging studies (ultrasound, CT, MRI, PET/CT). We present a clinical case of fat necrosis, confirmed by the immunohistochemical study, simulating recurrent kidney cancer. The patient underwent partial nephrectomy for renal cell carcinoma. After 6 months, radiological signs of tumor recurrence were detected in the resection area, due to which patient underwent laparoscopic nephrectomy. Immunohistochemical study indicated fat necrosis.