黃色肉芽腫性腎盂腎炎-特殊案例報告

李明儒^{1, 2, 3}、溫聖辰^{1, 2}

¹高雄醫學大學 附設醫院泌尿部，²醫學院；³高雄市立小港醫院

An unusual Presentation of a 8 cm Xanthogranulomatous cyst

Ming-Ru Lee ^{1, 2, 3}, Sheng-Chen Wen^{1, 2}

¹Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan；

²Department of Urology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan；

³Department of Urology, Kaohsiung Municipal Siaogang Hospital, Kaohsiung, Taiwan；

Background:

Xanthogranulomatous pyelonephritis (XGP) is considered a rare and distinct form of chronic kidney inflammation. It can be life-threatening if not treated properly. It often occurred to a middle-aged woman with the underlying disease of obstruction, stone, or recurrent infections. Clinical symptoms are nonspecific, and sometimes it accompanied with fever, flank pain, flank soreness or malaise. Pathogenesis is still not fully understood so far. For diagnosis, both computed tomography and magnetic resonance imaging can reveal characteristic lesion “bear paw sign”. However, the appearances can mimic other disease. Conservative antibiotic may be given during acute infection status and surgical resection is commonly recommended for complete treatment. We introduced a case of XGP with radiologic diagnosis of a Bosniac class III cyst in a 46-year-old asymptomatic woman without underlying disease mentioned.  

Case presentation:

A 46-year-old woman came to our clinic and mentioned there was a left renal complicated cyst(8.7cm x 7.8cm x 7.4cm) accidentally found when she got urinary tract infection 1 year ago. She denied fever after last time urinary tract infection. Also there was no dysuria, macroscopic hematuria, flank pain, flank soreness, malaise, nausea, vomiting, body weight loss noted. She denied any recent travel or family history and she had no associated history of diabetes mellitus, autoimmune, malignant disease. Laboratory examinations showed pyuria with urine cultured Escherichia Coli. Complete blood count level, serum urea, creatine, liver function, coagulation profile were normal. Computed tomography was arranged and a Bosniac class III cyst was diagnosed. Ths patient accepted robotic assisted laparoscopic left partial nephrectomy. Pathological examination showed cystic lesion walled by fibrous, granulation tissue with extensive infiltrate of foamy histiocytes, macrophages, lymphoplasma cells, neutrophils and multinucleated giant cells. Also renal tubular atrophy, global sclerosis and stromal fibrosis were presented. The final morphology suggested xanthogranulomatous pyelonephritis with cystic change. The patient discharged 5 days after the surgery and remained asymptomatic during clinic follow-up.

Conclusion:

XGP occurs in 1 % of all renal infection, and clinical symptoms were vague. Computed tomography is helpful for evaluation, but the characteristic features may misunderstanding with other disease sometimes. The differential diagnosis includes renal neoplasm, renal cell carcinoma, renal tuberculosis, angiomyolipoma, renal abscess. The only way to confirm the diagnosis is to biopsy or to resected the specimen for histopathologic analysis. Our case presents a big asymtomatic left renal complicated cyst resulted in XGP. This kind of feathers initially impressed as a Bosniak class III cyst without calculi in adult is extremely rare in the literature. Hence, to prevent inappropriate treatment, carefully evaluation and consider associate differential diagnosis are important.