合併黃色肉芽腫性前列腺炎與良性前列腺增生 - 一個罕見的病例報告

廖奕安、陳奕州

國立台灣大學附設醫院 泌尿部

國立台灣大學附設醫院雲林分院 泌尿部

A combination of Xanthogranulomatous prostatitis and benign prostate hyperplasia: a rare case report

Yi-An Liao¹, Yi-Jhou Chen²

¹Department of Urology, National Taiwan University Hospital, Taipei, Taiwan

²Department of Urology, National Taiwan University Hospital Yunlin branch, Yunlin, Taiwan

Abstract

Introduction:

The most common xanthogranulomatous inflammations are seen in the kidneys and gallbladder. If it grows in the prostate, it may mimic prostate adenocarcinoma or prostate abscess. Transrectal guided ultrasound of prostate and cystoscopy have no specific findings. Under microscopic field, immunohistochemical panel would be needed to make diagnosis. We present an unusual case of combination of anthogranulomatous prostatitis and benign prostate hyperplasia diagnosed after transrectal ultrasound-guided biopsy and laser transurethral enucleation.

Case presentation:

A 77 year-old man with coronary artery disease, congestive heart failure and hypertension was admitted to internal medicine ward due to urinary tract infection with initial presentation of fever, dysuria and voiding difficulty. After complete antibiotics treatment, fever and dysuria improved. Bladder echo and transrectal ultrasound of prostate revealed prostate enlargement. PSA level was elevated up to 25.516 ng/mL. Transrectal ultrasound-guided biopsy of prostate and laser transurethral enucleation of the prostate was arranged. Pathology of prostate biopsy and prostate enucleation revealed xanthogranulomatous inflammation and benign prostate hyperplasia.

Discussion:

Xanthogranulomatous prostatitis is a rare inflammatory lesion in prostate. It is a subtype of granulomatous prostatitis. The other subtypes include non-specific granulomatous prostatitis, tubercular granulomatous prostatitis, postsurgical granulomatous prostatitis and allergic granulomatous prostatitis.  According to current literature, its etiology may be idiopathic, iatrogenic, autoimmune origin and infectious origin. Infectious cause included bacteria, fungi, Treponema pallidum and Mycobacterium tuberculosis. Iatrogenic cause included BCG vaccine injection and post-radiotherapy. Nethertheless, most causes of xanthogranulomatous prostatitis remains unknown. The age of diagnosis is usually more than 60 years-old. If it combined with benign prostate hyperplasia, patients may have lower urinary tract symptoms. Digital rectal examination may reveal a enlarged prostate with or without hard nodules. Prostatic specific antigen may range from 0.5 ng/mL to 150 ng/mL according to current studies. Under transrectal guided sonography of prostate, the findings are divided into a hypoechoic nodule or a diffusely hypoechoic peripheral zone.  Nevertheless, current image studies, including transrectal ultrasound of prostate, computed tomography and magnetic resonance imaging still could not differentiate between xanthogranulomatous prostatitis and prostatic adenocarcinoma. The specific pathological features of xanthogranulomatous prostatitis is the presence of large amounts of foamy macrophages infiltrating the prostate tissue. It could mimic prostate adenocarcinoma with hypernephroid pattern. Immunohistochemical panel would be needed to distinguish between this two conditions. Immunohistochemistry staining in xanthogranulomatous prostatitis would be negative for broad spectrum cytokeratins and positive for CD68.Tracing back to our patient, the most possible etiology may be infection. Before receiving laser transurethral resection of prostate, he had history of urinary tract infection with the presentation of fever, urinary frequency and urinary difficulty. Urinary culture showed wild-type E.coli. In addition, he mentioned of episodes of dysuria and urge incontinence during outpatient department follow up in these few years, indicating the possibility of chronic urinary tract infection. Most recent studies suggest a better correlation of chronic infection with xanthogranulomatous prostatitis. Nevertheless, it may need further study to verify whether acute urinary tract infection may cause xanthogranulomatous prostatitis. Because under the microscopic field, xanthogranulomatous prostatitis may mimic prostate adenocarcinoma, regular follow up of PSA level is needed. Transrectal ultrasound guided prostate biopsy will be considered if PSA is elevated. In this patient, PSA level decreased from 25.516 ng/mL to 0.554ng/mL after laser transurethral resection of prostate. We would keep on follow up his PSA level to monitor the presence of prostate adenocarcinoma. 

Conclusion:

Xanthogranulomatous prostatitis is a rare inflammatory condition in prostate. There are no specific clinical signs and radiological features. Histopathology remains to be the only diagnosis method. Regular follow up of PSA level is needed because It may mimic prostate adenocarcinoma under microscopic field. Further studies is necessary to find out the clinical significance of xanthogranulomatous prostatitis.