Lower Urinary Tract Symptoms Due to Xanthoma of the Prostate After Kidney Transplantation: A Case Report.

Background. Prostatic xanthoma is a lesion of unknown cause that is often an incidental finding in patients undergoing needle biopsy or transurethral resection. To the best of our knowledge, we report on a unique case of a pure xanthoma without benign prostatic hyperplasia of the prostate in a patient with lower urinary tract symptoms manifested after kidney transplantation. Methods. A 62-year-old man was submitted for a kidney transplant in April 2018. He had no urinary complaints previous to the transplant. Since July 2019, he had complained of lower urinary tract symptoms. In October 2019, he had acute urinary retention being submitted to a transurethral resection of an estimated 47 g prostate. All measures of cholesterol, high-density lipoproteins (HDL), and low-density lipoproteins (LDL) were within the normal range-except triglycerides, which were mildly elevated in 2 measures. Results. The pathologic examination of the resected prostate showed pure xanthoma without benign prostatic hyperplasia. A similar lesion with a xanthomatous cell component is verruciform xanthoma. It is a rare benign lesion of unknown etiology not associated with underlying disorders of lipid metabolism that has been reported in patients with bone marrow, kidney, and liver transplant. Conclusions. We report a unique case of prostate enlargement caused by pure xanthoma in a patient with renal transplant. In absence of any apparent infection, normal cholesterol measures, and appearance of symptoms after the transplant and considering the morphologic similarity with verruciform xanthoma, a lesion also reported in transplanted patients, we speculate that the pathogenesis of the lesion in this particular patient may be related to immunosuppression.