Xanthogranulomatous Pyelonephritis: Intrahepatic and Intrathoracic Extension

A 32-year-old female presented to us with worsening cough and expectoration, low-grade fever, and malaise for 3 months. She gave a history of pregnancy loss secondary to urinary tract infection (UTI) a year back. At that time, she was told to have an obstructive right renal calculus. She also had a history of recurrent UTI in the past 1 year. She had no other comorbidities. Her clinical evaluation revealed an enlarged right kidney and reduced air entry in the right hemithorax. Radiological investigations revealed a large right kidney invading into the inferior surface of the right lobe of the liver and the right pleural space. A clinical diagnosis of xanthogranulomatous pyelonephritis was made, and she was advised nephrectomy. Intraoperatively, the right kidney was found to invade both the right lobe of the liver and the right pleural cavity through a right diaphragmatic defect. Histopathology of the kidney revealed the presence of foamy histiocytes suggestive of xanthogranulomatous pyelonephritis. Invasive xanthogranulomatous pyelonephritis is known, however, invasion into the extra-abdominal structures has not been reported in the literature. Our case is a rare manifestation of a rare clinical entity - xanthogranulomatous pyelonephritis.