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 Table of Contents  
Year : 2022  |  Volume : 9  |  Issue : 2  |  Page : 234-237

Malakoplakia of the prostate

1 Department of Pathology, MES Medical College and Paramedical Science, Perinthalmanna, Kolathur, Kerala, India
2 Department of Pathology, Yenepoya Medical College, Deralakatte, Mangalore, Karnataka, India

Date of Submission04-Mar-2022
Date of Acceptance02-Apr-2022
Date of Web Publication17-Jun-2022

Correspondence Address:
Dr. Prema Saldanha
Department of Pathology, Yenepoya Medical College, Deralakatte, Mangalore 575018, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/mgmj.mgmj_29_22

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Prostatic malakoplakia is a rare chronic inflammatory disease with only a few cases reported in the literature. It is believed to be caused by an impaired histiocytic response against bacteria. This is a case report of a 65-year-old man with a history of diabetes mellitus presenting with complaints of generalized weakness and fever of 4-day duration. Laboratory investigations showed pyuria, and urine culture showed Escherichia coli. An abdominal Computerised Tomography (CT) scan revealed left-sided pyelonephritis and a prostatic abscess. Double-J stenting with Trans-Rectal Ultrasound Scan (TRUS) biopsy was done. The biopsy showed features of malakoplakia of the prostate without any associated malignancy.

Keywords: Diabetes mellitus, Escherichia coli, malakoplakia, prostate

How to cite this article:
Gopalakrishnan NT, Saldanha P, Shamsudeen B. Malakoplakia of the prostate. MGM J Med Sci 2022;9:234-7

How to cite this URL:
Gopalakrishnan NT, Saldanha P, Shamsudeen B. Malakoplakia of the prostate. MGM J Med Sci [serial online] 2022 [cited 2023 Mar 28];9:234-7. Available from: http://www.mgmjms.com/text.asp?2022/9/2/234/347688

  Introduction Top

Malakoplakia is a rare inflammatory condition that develops secondary to a chronic  Escherichia More Details coli (E. coli) infection[1] that is believed to occur secondary to impaired host response.[2] Malakoplakia usually affects the genitourinary tract[1] with the most common site of involvement being the urinary bladder.[3] In the last 20 years, malakoplakia affecting extravesical sites[3] such as the colon, stomach, lungs, liver, bones, uterus, and skin has been reported with increasing frequency.[3] Some of these cases may pose diagnostic and therapeutic difficulties initially, because of the failure to recognize the disease process as it has a benign nature.[3]

Malakoplakia of the urinary bladder affects women more commonly than men and is more common between the fifth and seventh decades of life.[1],[4] In male patients, the prostate may also be affected along with the bladder.[1] Prostatic involvement is very rare, and it may be mistaken clinically for prostatic malignancies because of the formation of a prostatic mass and the thickening of the bladder wall.[1] In the prostate, malakoplakia can be a convincing mimic of malignancy, with clinical and imaging characteristics being very similar between the two.[2] Malakoplakia has even been mistaken for locally advanced prostate cancer on multiparametric magnetic resonance imaging of the prostate.[5] Histopathological examination is the only possible definitive diagnosis. Here, we report a case of malakoplakia of the prostate because of its rarity.

  Case report Top

A 65-year-old man, a known diabetic patient, presented with complaints of generalized weakness and fever of 4-day duration. On investigation, the patient’s glycosylated hemoglobin value was 9.1% (normal: 4.2%–6.2%). Urine showed pyuria, and urine culture was positive for E. coli organisms. An abdominal Computerised Tomography (CT) scan showed left-sided pyelonephritis. The prostate showed a peripherally enhancing lesion on the left side, and a diagnosis of the prostatic abscess was offered with a suggestion to correlate with Prostate-Specific Antigen (PSA) values. The PSA value was 2.04 ng/mL (normal). The urologist suggested left Double-J stenting and Trans-Rectal Ultrasound Scan (TRUS) biopsy to rule out malignancy. The biopsy from the prostatic tissue showed sheets of histiocytes with abundant eosinophilic cytoplasm along with basophilic round, concentrically-layered intracytoplasmic inclusions consistent with Michaelis–Gutmann bodies (MGBs). A diagnosis of malakoplakia of the prostate was made [Figure 1] and [Figure 2]. There was no malignancy noted. These MGBs were positive for Perls’ stain [Figure 3] and von Kossa stain [Figure 4]. The patient was treated symptomatically with antibiotics following which the patient improves and was discharged with the advice of regular physical examination and PSA serum testing.
Figure 1: Sheets of histiocytes with abundant eosinophilic cytoplasm and eccentric nucleus (H&E, 20×)

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Figure 2: Basophilic round concentrically layered intracytoplasmic inclusions (arrow) consistent with Michaelis–Gutmann bodies (H&E, 40×)

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Figure 3: Michaelis–Gutmann bodies positive for Perls’ stain for iron (Perls’, 40×)

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Figure 4: Michaelis–Gutmann bodies positive for von Kossa stain for calcium (von Kossa, 40×)

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  Discussion Top

Malakoplakia was first defined by Michaelis and Gutmann in 1902. Hansemann coined the term malakoplakia, in 1903, based on its gross appearance affecting the urinary bladder. The term was derived from a combination of words, malakos (soft) and plakos (plaque) in ancient Greek.[1],[4] Malakoplakia of the prostate was defined for the first time in 1959.[3],[4] Prostatic malakoplakia is very rare with approximately 50 cases reported in the literature so far.[2]

Although malakoplakia is a rare chronic inflammatory disease with disputed etiology and pathogenesis,[4] it is believed to be caused by an impaired histiocytic response against bacteria.[2] It involves the genitourinary system, typically manifesting as yellow soft plaques or nodules that are characterized by the accumulation of macrophages.[1] Even though there is an association of this condition with bacteria, viruses, or parasites, the frequent occurrence of gram-negative bacterial infections such as E. coli, Klebsiella pneumoniae, and Proteus makes bacterial infection a significant etiologic factor in this disease.[4] About 80%–90% of the malakoplakia patients’ urine cultures grow E. coli.[1] Another thought is that because E. coli infection of the genitourinary tract is very common and the occurrence of malakoplakia is rare, there could have been other host factors that may modify the response of the host to this primary etiological factor.[4] It is considered that the pathogenic mechanism occurs because of a defective immune response to these microbial agents. Some authors have also reported the presence of an association between this disease and immunosuppression,[1] as it is more common in patients suffering from either primary or acquired immunodeficiency conditions such as diabetes, malignancy, or HIV/AIDS.[2]

The clinical features of malakoplakia are nonspecific, and it can mimic malignancy. Even though malakoplakia has been associated with many types of malignancies, no case reports are suggesting the malignant transformation of this condition.[4] There are nine reported cases of malakoplakia and associated prostatic adenocarcinoma, but the two types of pathologies have not occurred simultaneously. Some authors have proposed that malakoplakia is a possible complication of prostate biopsy, probably because of the infection following the biopsy.[2]

Imaging studies have difficulties in differentiating malakoplakia from malignancy. As documented in the literature, malakoplakia displays hypoechoic lesions on transrectal ultrasound, which are consistent with the sonographic appearance of the prostatic cancer. Magnetic Resonance Imaging (MRI), which is considered a powerful tool in the evaluation of prostate pathology, also fails to differentiate between the two conditions. Until now, the definitive and accurate diagnosis of malakoplakia depends only on the histopathological examination.[2]

Histologically, malakoplakia is a chronic granulomatous disorder. Microscopic examination reveals inflammatory infiltrate of plasma cells and histiocytes. These histiocytes can be differentiated from the tumor cells by their uniform size, round or oval vesicular nuclei, and finely vacuolated cytoplasm in the former. The characteristic finding of this condition is the presence of MGB within the cytoplasm of these histiocytes.[4] MGBs consist of phagolysosomes including bacterial debris. They also contain calcium hydroxyapatite and iron.[1] Histochemical stains such as periodic acid-Schiff stain demonstrate the bacteria in the macrophages, whereas Von Kossa and Perls’ stains are positive for calcium and iron, respectively.[1],[4]

Malakoplakia can also be mistaken for nonspecific granulomatous prostatitis in the histopathological examination of the needle biopsy specimen. Cases that morphologically resemble malakoplakia but do not contain MGBs are referred to as nodular histiocytic prostatitis. Formerly, cases of malakoplakia have been diagnosed as granulomatous prostatitis because of a lack of awareness of this entity.

Intravesical Bacillus Calmette-Guerin therapy for bladder carcinoma may cause granulomatous prostatitis.[1] Misdiagnosis may occur because the histiocytic infiltration resembles the tumor cells in a clear-cell type of prostatic carcinoma. Hence, a diagnostic workup for malakoplakia should include careful histopathological examination accompanied by histochemical and immunohistochemical tests for an accurate diagnosis.[1]

The literature describes treatment with antibiotics to resolve voiding symptoms.[2] Antibiotics penetrate the macrophage cell membrane and cure bacterial infection.[1] If antimicrobials fail, transurethral or even open resection of the prostate is suggested as an option.[1],[2] Regular follow-up of the patient is also suggested.

  Conclusion Top

An important reason for describing and defining prostatic malakoplakia is that it can be falsely misinterpreted as prostatic carcinoma. An awareness of this condition and the demonstration of typical MGBs in the biopsy help in arriving at an accurate diagnosis.

Institutional ethics committee (IEC) clearance

In this case, written patient consent was not taken as there are no patient identifiers in the brief history included. Also, this case report mainly deals with the histopathological findings and differentiating malakoplakia from malignancy. As no research was done, the clearance from Institutional Ethics Committee was not required.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Kahraman DS, Sayhan S, Diniz G, Ayaz D, Karadeniz T, Can E A pitfall in transrectal prostate biopsy: Malakoplakia evaluation of two cases based on the literature review. Case Rep Pathol 2014;2014:150972.  Back to cited text no. 1
Ho M, Wu J, Skinnider B, Kavanagh A Prostatic malakoplakia: A case report with review of the literature. J Surg Case Rep 2018;2018: rjy050.  Back to cited text no. 2
McClure J Malakoplakia of the prostate: A report of two cases and a review of the literature. J Clin Pathol 1979;32:629-32.  Back to cited text no. 3
Gidwani A, Gidwani S, Khan A, Carson J Concurrent malakoplakia of cervical lymph nodes and prostatic adenocarcinoma with bony metastasis: Case report. Ghana Med J 2006;40:151-3.  Back to cited text no. 4
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 Endourology Case Rep 2017;3:74-7.  Back to cited text no. 5


  [Figure 1], [Figure 2], [Figure 3], [Figure 4]


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