Granulomatous prostatitis

Differential
diagnosis of uncommon prostate diseases: combining mpMRI and clinical information. Nonspecific granulomatous prostatitis in a 57-year-old male who experienced frequency, urgency and burning micturition for 1 month, with a serum PSA level of 18.67 ng/mL transiting to 5.04 ng/mL. a–c T2WI, DWI at a b-value of 1400 s/mm2 and ADC maps show a diffusely and multifocally low signal intensity in the surrounding parenchyma on T2WI (a), a high signal intensity on DWI (b) and low ADC values (arrows on c in the prostate, with extraprostatic extension (arrowheads on a). (d) DCE imaging shows diffuse and multifocal areas of enhancement. The abnormal appearances of the prostate in the images shown in a–d result in a PI-RADS score of 5
insightsimaging.springeropen.com • CC-by-4.0
Differential
diagnosis of uncommon prostate diseases: combining mpMRI and clinical information. Nonspecific granulomatous prostatitis in a 57-year-old male with dysuria and urinary retention for 1 month and a serum PSA level of 13.22 ng/mL. a, b DWI at a b-value of 1400 s/mm2 and ADC maps show a focal nodule with obviously restricted diffusion (arrow) in the left peripheral zone of the prostate. c–e DCE imaging shows early and prolonged enhancement of the nodule (arrow). The appearances of the nodule in a–e result in a PI-RADS score of 4. Note the prostatic hyperplasia in the TZ (☆), which may have caused the symptoms of dysuria and urinary retention
insightsimaging.springeropen.com • CC-by-4.0
Differential
diagnosis of uncommon prostate diseases: combining mpMRI and clinical information. Diffuse granulomatous prostatitis in a 67-year-old male. a T2WI shows diffuse swelling of bilateral peripheral zones and the signal intensity is diffusely decreased (arrow). b T1WI shows a diffusely increased signal intensity in the bilateral PZs (arrow). c DCE imaging shows a rapid enhancement of bilateral PZs (arrow). Note the central necrosis in the lesion (☆)
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Radiopaedia • CC-by-nc-sa 3.0 • de

Granulomatous prostatitis is a nodular form of chronic prostatitis. It is usually diagnosed on biopsy.

Pathology

Causes
Subtypes

Several classification systems exist. A frequently used classification specifies the following subtypes:

  • non-specific granulomatous prostatitis (NSGP): considered one of the commonest subtypes
  • infectious
  • indeterminate

An alternate classification system has also been described:

  • non-specific granulomatous prostatitis
  • tubercular granulomatous prostatitis
  • postsurgical granulomatous prostatitis
  • allergic granulomatous prostatitis
  • xanthogranulomatous prostatitis
Histology

Histological appearances are related to the underlying subtype .

Radiographic features

General features

Often there is no definite imaging finding to allow the diagnosis of granulomatous prostatitis to be made or, indeed, to differentiate it from prostatic carcinoma .

Widening of the prostatic urethra, however, may be a useful feature in differentiation from cancer .

Ultrasound

Ultrasound findings are divided into a hypoechoic nodule (~70%) or a diffusely hypoechoic peripheral zone (~30%)

MRI

Three morphological MRI patterns have been described which are diffuse, nodular (tumor-like), and cystic with mural nodule .

Signal characteristics include

  • T2: affected regions hypointense
  • C+ (Gd): no enhancement following Gd-DTPA

History and etymology

It was first described by F H Tanner and J R McDonald in 1943 .