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  Table of Contents  
LETTER TO THE EDITOR
Year : 2021  |  Volume : 58  |  Issue : 2  |  Page : 307-309
 

Mimicker of malignancy, malakoplakia presenting as PI-RADS 5 lesion in mp-MRI—A case report


1 Department of Urology, Amrita Institute of Medical Sciences and Research Center, Kochi, Kerala, India
2 Department of Pathology, Amrita Institute of Medical Sciences and Research Center, Kochi, Kerala, India

Date of Submission28-Feb-2020
Date of Decision24-Apr-2020
Date of Acceptance07-Jul-2020
Date of Web Publication11-May-2021

Correspondence Address:
Abhishek Laddha
Department of Urology, Amrita Institute of Medical Sciences and Research Center, Kochi, Kerala
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijc.IJC_164_20

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How to cite this article:
Laddha A, Pooleri GK, Bindhu M R, Thomas A. Mimicker of malignancy, malakoplakia presenting as PI-RADS 5 lesion in mp-MRI—A case report. Indian J Cancer 2021;58:307-9

How to cite this URL:
Laddha A, Pooleri GK, Bindhu M R, Thomas A. Mimicker of malignancy, malakoplakia presenting as PI-RADS 5 lesion in mp-MRI—A case report. Indian J Cancer [serial online] 2021 [cited 2021 Jun 24];58:307-9. Available from: https://www.indianjcancer.com/text.asp?2021/58/2/307/315802





  Introduction Top


Malakoplakia is a rare inflammatory condition that frequently involves the genitourinary system. Isolated involvement of the prostate is rare and is commonly misdiagnosed as a malignancy in imaging.[1],[2] We report a case of a 53-year-old man presenting with voiding lower urinary tract symptoms (LUTS) who was found to have a hard nodule on the left side upon digital rectal examination (DRE), elevated prostate specific antigen (PSA), and prostate imaging reporting and data system (PI-RAD) 5 lesion on multi-parametric - magnetic resonance imaging (mp-MRI) and was diagnosed to have Malakoplakia on 12 core MRI-cognitive biopsy of the prostate.


  Case Report Top


A 53-year-old man with no comorbidity and normal immune status, presented to us with voiding LUTS and on evaluation was found to have a hard nodule on the left side of the prostate on DRE and elevated PSA of 9.54 ng/dL (double checked at 2 weeks interval). He had a significant past history of symptomatic urinary tract infection (2 episodes, no urine culture was done) and one episode of urinary retention in the last one year. In view of high clinical suspicion of prostate cancer, he was advised mp-MRI of the prostate. An mp-MRI was done using 3T MRI (General Electric Discovery 750W, Boston, USA), with a 16-channel body array coil (T1- and T2-weighted whole pelvis, T2-weighted triplanar HR SFOV, diffusion-weighted imaging at b10, b400, b800, and b1400, and dynamic contrast-enhanced imaging) obtained in accordance with the standardized protocols set out by the prostate imaging and reporting data system (PI-RADS v2). On mp-MRI, he had a hypointense lesion of more than 2 cm in size on the left side with diffusion restriction in both the peripheral and transitional zone with a low apparent diffusion coefficient (ADC) component of the diffusion restricting areas and significant enhancement on the postcontrast study, large lesion with diffusion restriction, and significant postcontrast enchantment all suggestive of PI-RADS 5 (PI-RADS v2) lesion [Figure 1]. In view of the above findings, he underwent 12-core MRI-cognitive biopsy using transrectal ultrasound guidance with BK flex focus 800(BK Medical, Mileparkan, Denmark). All six cores from the left side (taken from suspicious PI-RADS 5 lesion on MRI) had prostatic tissue showing dense inflammation with collections of histiocytes, multinucleated giant cells with attempted granuloma formation, and dense superimposed neutrophilic inflammation. A few of the histiocytes showed pale bodies in the cytoplasm, suggestive of Michaelis–Gutmann bodies. In view of the above findings, the diagnosis of malakoplakia was made [Figure 2]. The urinary examination and cultures before biopsy were normal. The patient was advised antibiotics for two weeks (trimethoprim-sulfamethoxazole) and on subsequent follow-up he was doing well and on DRE his palpable nodule was no longer palpable. He was advised to continue alpha-blockers and he is doing well on six months follow-up.
Figure 1: mp-MRI of prostate showing the PI-RADS 5 lesion on left side. (a) The image shows a DWI sequence with diffusion restriction in both the peripheral and transitional zones on the left side. (Blue arrow). (b) Low-ADC component of the diffusion restricting areas (corresponding to areas in Figure 1a) (Blue arrow). (c) Image showing T2 hypointensity in comparison to the surrounding muscle (Blue arrow). (d) Postcontrast image showing significant enhancement in the left lobe (Blue arrow), DWI=Diffusion-weighted imaging, mp-MRI=multi-parametric - magnetic resonance imaging,PI-RAD=prostate imaging reporting and data system, ADC=apparent diffusion coefficient

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Figure 2: Histopathology images (a and b) 10× image and 40× images showing dense inflammation with collections of histiocytes, multinucleated giant cells. (c) Histiocytes showing pale bodies in the cytoplasm showing Michaelis–Gutmann bodies (black arrow). (d) Perls' staining

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His follow-up PSA at three months and six months were 2.4 and 2.7 ng/dL, respectively.


  Discussion Top


Malakoplakia is a rare granulomatous disease resulting from the inadequate killing of bacteria by macrophages or monocytes that have defective phagolysosomal activity. They usually present in individuals who are immunocompromised but can occur in immunocompetent individuals. Malakoplakia commonly involves a genitourinary system with around 70% of cases involving bladder.[3] It has been reported to occur in kidney, testes, adnexa, and rarely in the prostate (less than 50 cases reported so far).[3] Most patients have a documented history of urinary tract infection and the most commonly identified organism is E. coli (80%).[2]

Radiologically, it mimics cancer in most cases and diagnosis remains challenging. On transrectal ultrasound, it usually presents as hypoechoic lesion.[1] When extensive, it can mimic locally advanced prostate cancer as well. The diagnosis of malakoplakia in a biopsy does not rule out the presence of prostate cancer. More than nine cases of malakoplakia and prostate adenocarcinoma existing together have been reported in the literature[2],[4] but in most cases, the diagnosis of prostate cancer was made on repeat biopsy at a later date. In fact, multiple biopsies, with possible associated infections may increase the incidence of malakoplakia of the prostate in patients who are on follow-up for active surveillance of prostate cancer. mp-MRI is now considered as a standard tool for diagnosis and staging of prostate cancer. As the incidence of malakoplakia may rise further due to repeat biopsies, mp-MRI should be read with caution in such patients.[4]

Similar two cases of patients presenting with elevated PSA and PI-RADS 4 and 5 lesions have been described in the literature. The first patient had a history of urosepsis in the past with persistently elevated PSA on follow-up. His MRI was suggestive of well-circumscribed right apical homogeneous, hypointense, and peripheral zone lesion on T2-weighted imaging of size 2.8 cm. The lesion was also markedly hyperintense on high b-value diffusion-weighted imaging and hypointense on the apparent diffusion coefficient map suggestive of a PI-RADS 5 lesion and prostate health index of 187.[5] The second patient had previous two negative biopsies with persistently elevated PSA and was on immunosuppressive drugs (status post renal transplant) and upon MRI he was found to have a diffuse band like low signal intensity measuring 1.6 × 1.5 cm lesion in the posterior mid gland and apical peripheral zone without evidence of prostatic capsule disruption with seminal vesicle extension. Diffusion-weighted imaging (DWI) images were suggestive of high signal intensity with evidence of significant restriction and dynamic contrast-enhanced (DCE) images showed early enhancement suggestive of PI-RADS 4 lesion.[6] Although, mp-MRI is highly sensitive and specific for prostate cancer, interpretive and technical pitfalls resulting from prostatic infection and disease processes such as malakoplakia may be encountered, which can mimic prostate cancer.

The history of urinary retention and recurrent urinary tract infection may in hindsight suggest the possibility of malakoplakia in our case, but the clinical diagnosis is difficult without conclusive evidence provided with biopsy. The optimal management of prostatic malakoplakia is not well defined. Most cases are managed with antibiotics (fluoroquinolones and trimethoprim-sulfamethoxazole are used commonly) which may help in the resolution of lower urinary tract symptoms. Surgical resection (Transurethral or Open) may be considered in refractory patients.[1] Our patient responded well to two weeks of trimethoprim-sulfamethoxazole with complete resolution of symptoms and DRE findings. Many authors have reported the persistence of malakoplakia on follow-up biopsy in these patients even with clinical resolution of symptoms. Due to the limited number of cases, adequate follow-up of these patients is not well defined. We have planned to follow-up this patient with three-month PSA and yearly DRE along with mp-MRI in case of clinical suspicion of recurrent disease or rising PSA.


  Conclusion Top


Our case signifies the possibility of benign disorders like malakoplakia and prostatitis in prostatic biopsy even when clinical, radiological, and laboratory findings suggest a high possibility of prostate cancer. Our case highlights a rare differential diagnosis which can mimic prostate cancer in mp-MRI.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Wagner D, Joseph J, Huang J, Xu H. Malakoplakia of the prostate on needle core biopsy: A case report and review of the literature. Int J Surg Pathol 2007;15:86-9.  Back to cited text no. 1
    
2.
Medlicott S, Magi-Galluzzi C, Jimenez R, Trpkov K. Malakoplakia associated with prostatic adenocarcinoma: Report of 4 cases and literature review. Ann Diagn Pathol 2016;22:33-7.  Back to cited text no. 2
    
3.
Long JP, Althausen AF. Malacoplakia: A 25-year experience with a review of the literature. J Urol 1989;141:1328-31.  Back to cited text no. 3
    
4.
Dale R, Metcalfe M, Chang S, Jones E, Black P. Malakoplakia of the prostate masquerading as locally advanced prostate cancer on mpMRI. Can Urol Assoc J 2015;9:910-2.  Back to cited text no. 4
    
5.
Heah NH, Tan TW, Tan YK. Malakoplakia of the prostate as a mimicker of prostate cancer on Prostate health index and magnetic resonance imaging-fusion prostate biopsy: A case report. J Endourol Case Rep 2017;3:74-7.  Back to cited text no. 5
    
6.
Velasquez MC, Smith PJT, Prakash NS, Kava B, Kryvenko ON, Castillo-Acosta R, et al. Malakoplakia of the prostate diagnosed on multiparametric-MRI ultrasound fusion guided biopsy: A case report and review of the literature. Urol Case Rep 2017;18:94-6.  Back to cited text no. 6
    


    Figures

  [Figure 1], [Figure 2]



 

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