An Uncommon Mimicker

Nachiketh Soodana Prakash MD MS1, Sanoj Punnen

MD1 and Leonardo Kayat Bittencourt, MD, PhD2

1Depatment of Urology, University of Miami, Miami, FL, USA.2Department of Radiology, Fluminense Federal University, Rio de Janeiro, Brazil.

Case

• 64 year old male.

• Follow-up of serial PSA elevation: 10ng/ml

• DRE: abnormal firmness on the right lobe.

• Previous negative biopsy with right mid core showing

focus of high grade PIN with adjacent small atypical

glands.

• H/O Renal transplant on immunosuppression drugs.

Episode of UTI 3 months back urine culture showing

E.coli and was treated for the same.

• mpMRI was ordered for biopsy planning.

Imaging findings

• T2WINon‐circumscribed, ill-defined, homogeneously T2-hypointense non-bulging lesion in the bilateral posterior mid gland and apex at the peripheral zone, measuring 6.1 x 1.5 cm (arrows).

Interestingly, there were no signs of gross extraprostatic extension, and neither there were enlarged lymph-nodes.

T2WI

ADC map

High B-valueDWI

Imaging Findings

• DWI

High signal intensities on

high b-value DWI, as well

as markedly impeded

diffusion on the ADC map

(arrows).

pre-contrast DCE

Early arterial phase DCE

Imaging Findings

• DCEDynamic contrast study

demonstrates early

enhancement throughout

the whole lesion.

PI-RADS Scoring

• T2WI = 5

• DWI = 5

• DCE = + (positive)

• PI-RADS Score = 5

Dominant parameter for PZ lesions

TRUS- guided Fusion biopsy.

Discussion

• Extensive highly-suspicious lesion in the whole PZ.

PI-RADS Score = 5.

• No signs of gross extraprostatic extension or enlarged

lymph-nodes.

• No evidence of bone metastases.

• PSA levels around 10 ng/ml.

• History of immunosuppression and UTI.

• Therefore, an alternative hypothesis of

chronic/granulomatous prostatitis was included in the

differential diagnoses.

• MR-TRUS fusion guided biopsy revealed prostatic

malakoplakia.

Pathology: Malakoplakia

• Pathology: Atrophic Prostate Glands with Chronic Inflammation with

significant amount of Histiocytes. (20x).

Pathology: Malakoplakia• Pathology: 60x - high power magnification showing Michaelis–Gutmann

bodies(MG bodies) which are pathognomic feature of Malakoplakia.

Malakoplakia• A form of chronic inflammation thought to be associated

with E. coli or K. pneumoniae infection.

• Association with immunosuppression has also been hypothesized.

• Most commonly found in the Bladder. Extra-genital sites have also been rarely described.

• Malakoplakia of the prostate is an extremely rare condition, and is known to mimic prostate cancer in terms of imaging findings.

• Patients can be treated with antibiotic therapy.

• There are no pathognomonic imaging findings. However, this condition should be suspected in patients with a typical clinical history, associated to mpMRI findings that resemble those of chronic/granulomatous prostatitis.

M. Niemierko, B. Kuzaka. Malacoplakia of the prostatePrzegl Lek, 62 (2005), pp. 825–826

Acknowledgements

• Oleksandr Kryvenko MD : University of Miami, Department of

Pathology.