Xanthogranulomatous prostatitis: Rare presentation of rare disease.

Granulomatous inflammation of the prostate is a rare type of inflammation of the prostate. It is of various types, with the non-specific type of granulomatous inflammation being the most common. Xanthogranulomatous prostatitis is a rare type of granulomatous prostatitis of which very few cases have been reported. Histologically it is characterized by the presence of pale-looking foamy macrophages. It can be an incidental finding after transurethral resection of the prostate (TURP), although it may mimic prostatic malignancy clinically, biochemically, and rarely histologically. We report a rare case of xanthogranulomatous prostatitis which presented as a prostatic abscess, a presentation never reported in literature so far. The patient was managed with TURP.

INTRODUCTION

Granulomatous inflammation is an uncommon cause of inflammation of the prostate. It has been classified into different types, the most common being the non-specific or idiopathic type. Xanthogranulomatous prostatitis is a very rare type of granulomatous prostatitis. It has to be differentiated from the most common and usually a self-limiting, non-specific type of granulomatous inflammation. The xanthogranulomatous type of inflammation can be an incidental finding after transurethral resection of the prostate or it can simulate prostatic malignancy clinically, radiologically, and biochemically, with PSA elevation. We report a case of xanthogranulomatous prostatitis with clinical and radiological similarity to acute prostatic abscess, a presentation not reported so far.

CASE REPORT

A fifty-two-year old male patient presented to us with a catheter in situ, put in 14 days back, when he had developed acute urinary retention and high grade fever. The patient was started on oral antibiotics when referred to us. He had no prior history of lower urinary tract symptoms (LUTS). He did not have any significant past surgical or medical history including diabetes mellitus or tuberculosis. The general physical and per abdomen examination was normal. The external genitalia were normal and on digital rectal examination, the prostate was grade II, enlarged with a boggy left lobe. Biochemical investigations including a complete hemogram, creatinine, and random blood sugar were essentially normal. PSA was not done, as it was expected to be elevated, as the presentation was identical to prostatic abscess. Ultrasonography showed normal upper tracts and bladder. On a transrectal ultrasound, the prostate was 52 cc in volume with multiple hypoechoic areas, suggestive of prostatic abscess [Figure 1]. Under antibiotic cover, the patient underwent transurethral resection of the prostate (TURP). The lateral lobes were mildly enlarged. After superficial resection minimal pus was seen from small, occasional pus pockets. Postoperative recovery was uneventful except for mild urge incontinence, which settled within a week postoperatively. The histopathology was reported as acute on chronic xanthogranulomatous prostatitis with prostatic hyperplasia [Figure 2]. There was no evidence of malignancy.

Figure 1

Prostatic abscess on ultrasound

Figure 2

Photomicrograph showing foam cells

DISCUSSION

Xanthogranulomatous inflammation is pathologically distinguished by inflammatory response of foamy macrophages or histiocytes. It is commonly seen in certain sites such as the kidneys and gall bladder, and xanthogranulomatous pyelonephritis is a well-described entity. However, in the prostate it is rare, with less than 10 cases reported.[1] It is one of the types of granulomatous inflammation of the prostate, which itself is quite uncommon.[2] It is classified into the following types:

Non-specific (idiopathic)

Infective

Iatrogenic (post surgery)

Xanthogranulomatous

Malacoplakia

Associated with systemic granulomatous diseases and allergy

The non-specific type is the most common type of granulomatous inflammation. It is important to distinguish it from other types of granulomatous inflammation, as it has a self-limiting course, unlike other rarer types.[2] Pathologically xanthogranulomatous prostatitis shows features of lobulocentric accumulation of inflammatory cells, including, lymphocytes, plasma cells, and sometimes polymorphs with eosinophils. There are a large number of foamy macrophages or histiocytes admixed with other inflammatory cells. These histiocytes can occur in sheets, giving a pale appearance on low-power microscopy. T lymphocytes have been associated with the damaged epithelium and B cells in the follicles. An immunological panel has also been proposed to distinguish granulomatous inflammation from high-grade prostatic carcinoma, which it may resemble.[1] The exact cause for xanthogranulomatous inflammation is not known. It has been associated with hyperlipedemia.[2] Average age of presentation is the early sixties with a range from twenties to the very elderly. It may present with LUTS or lower urinary tract infection, which may include urethral discharge.[3] Presentation similar to acute prostatic abscess has not been reported so far. On rectal examination, the prostate may be hard and nodular mimicking prostatic carcinoma. PSA can be elevated, with a reported rise of up to 150 ng/ml in one case.[1] The transrectal ultrasound and MRI cannot distinguish this entity from prostatic malignancy, but generally the ultrasound shows hypoechoic lesions.[14] Final diagnosis is only by histopathological examination of the prostate. During TURP, the prostatic urethra has been described as being inflamed and the TURP chips appear yellowish, but without abscess cavities.[1] Despite the well-defined abscess cavities seen on transrectal ultrasound in this case, only minimal pus pockets were observed intra-operatively. Post TURP, a rectovesical fistula had been reported in one case of xanthogranulomatous prostatitis, which was managed with transverse colostomy.[5] In conclusion, in all cases of prostatic abscesses, xanthogranulomatous prostatitis is a rare possibility and should be kept in mind.