Exuberant Malakoplakia of the Prostate Presenting as Prostatic Abscesses in an Immunocompromised Patient

Abstract

Background: Malakoplakia is a rare benign lesion, usually associated with deficient intralysosomal degradation of microorganisms, more commonly, Escherichia coli. Malakoplakia occurs in various organ systems, the most frequently affected site being the urinary bladder. We report a rare case of isolated extensive malakoplakia involving the prostate, diagnosed on transurethral resection performed for radiologically suspected prostatic abscesses. Case Presentation: A 61-year-old African American male presented with symptoms of urinary obstruction for the past 2 months. His medical history was significant for immunosuppression (liver transplantation 3 months prior and diabetes mellitus). He reported four episodes of E. coli-associated urinary tract infection after his liver transplantation. Serum prostate specific antigen was 1.83 ng/cc (normal inferior to 4 ng/cc), and urine culture was positive for E. coli sensitive to ceftriaxone. Pelvic magnetic resonance imaging was suggestive of prostatitis with prostatic abscesses; cystoscopy was unremarkable. The patient was started on intravenous ceftriaxone therapy. A standard bipolar transurethral resection of the prostate was performed, and purulent-like material was encountered in the resected tissue. Histologic examination demonstrated extensive infiltration and replacement of the prostatic tissue by sheets of pink histiocytes with targetoid inclusions consistent with Michaelis-Gutmann bodies, ultimately confirming malakoplakia of the prostate. Conclusion: Prostatic malakoplakia is an unexpected diagnosis in patients suspected of having malignancy or prostatitis. Its exact pathogenesis is unknown, but it involves defective bacterial degradation after phagocytosis. E. coli is often cultured from the patients' urine. Immunosuppression, present in our patient, is a well-known associated factor. Prostatic malakoplakia can radiologically masquerade as prostatic adenocarcinoma, despite the use of cutting-edge imaging technology. With the growing use of multiparametric 3T prostate magnetic resonance imaging to screen for prostate cancer, it is possible that urologists, radiologists, and pathologists will encounter prostatic malakoplakia more frequently in the future.