Xanthogranulomatous inflammation is an uncommon benign inflammatory disease process characterized by aggregation of lipid laden foamy macrophages, among other inflammatory cells such as lymphocytes and plasma cells. These lesions have previously been identified in many anatomic sites, most frequently in the kidney and renal pelvis, but also occasionally seen in the urachus. The clinical relevance of this disease is that it often mimics malignancy, and preoperative imaging is unable to differentiate between the two.

Case presentation: Case 1 depicts a 53 year old gentleman who presented with lower urinary tract symptoms (LUTS), and suprapubic mass and tenderness. Imaging showed a 6cm supravesical mass suggestive of a urachal origin. Patient underwent excision of urachal tumour, umbilicus, partial cystectomy, and bilateral pelvic lymph node dissection. The histopathological examination showed xanthogranulomatous inflammation of the urachus (XGU).

Case 2 depicts a 68 year old lady who presented with a lower urinary tract infection (UTI). Imaging showed a 5.8cm solid enhancing mass with cystic component in the left kidney. A renal biopsy was performed and histopathology showed fibro-connective and fibro-adipose tissue with florid xanthogranulomatous inflammation

Given the resemblance between xanthogranulomatous inflammation and carcinoma on diagnostic imaging, it is important to keep this entity as a differential in the diagnosis of urachal and renal lesions. Histopathologic examination is necessary for diagnosis. Nephrectomy is the standard surgical treatment for XGP, while excision of urachus, umbilicus and partial cystectomy for XGU is established. Further research is needed surrounding the utility of frozen section analysis and pelvic lymph node dissection in surgical therapy.