Malakoplakia of the prostate gland--report of two cases and review of the literature

Case report: Prostatic malakoplakia: a rare disease that has a profile mimicking prostate cancer

Prostatic malakoplakia (PMP) is a rare inflammatory disease, and misdiagnosis on imaging is a major reason for unnecessary punctures; however, information on imaging is even rarer. Five patients with PMP between May 2022 and February 2023 were enrolled in this study to summarize the imaging manifestations. All patients underwent ultrasound (US)-guided prostate biopsy and were confirmed by pathology, and the presence of prostate cancer was also excluded by pathology. The five patients, with a median age of 71 years (range = 58-74 years), had a median total prostate-specific antigen (T-PSA) of 10.40 ng/mL (range = 1.74-63.42 ng/mL). In two patients, chest computed tomography showed pulmonary infections. All patients underwent magnetic resonance imaging (MRI). Of these patients, four had a Prostate Imaging-Reporting and Data System (PIRADS) score of 5, while one had a score of 4. The lesions were mostly distributed in the peripheral zone of the prostate and appeared as a high signal on T1-weighted imaging (T1WI) and a low signal on T2-weighted imaging (T2WI). In the US examination, four patients had abnormal prostate morphology, with an unsmooth envelope and non-uniform parenchymal echogenicity. Four patients had increased prostate volume. US showed a hypoechoic nodule with non-uniform internal echogenicity, and an abundant internal blood flow signal was detected by color Doppler US. PSA, MRI, and US were not specific for PMP in our study, but we found that a history of co-infection may be helpful in an accurate diagnosis and to avoid unnecessary biopsy.

Malakoplakia prostate presenting as urinary retention: a report of two cases and review of the literature

Malakoplakia is a rare chronic inflammatory condition, which primarily occurs in genitourinary tract, with prostatic malakoplakia being extremely rare. We present two cases of acute urinary retention, with clinically firm nodular prostate and a raised serum prostate-specific antigen. Transrectal ultrasound-guided prostatic biopsy showed features of malakoplakia. There was a significant reduction of size of prostate on transrectal ultrasonography after 4 weeks of antibiotics. However, one patient had failed trial without catheter and was subjected to transurethral resection of prostate. The biopsy of the prostatic chips also showed features of malakoplakia. Other patient improved symptomatically after antibiotics and was managed conservatively. Both the patients are on regular follow-up and are asymptomatic. Prostatic malakoplakia presenting as urinary retention is very uncommon with around 12 cases in the literature. Recognition of prostatic malakoplakia is important because clinically it can masquerade prostatic malignancy. Treatment with antibiotics is necessary before subjecting the patients for surgery in patients with obstructive symptoms.

Benign mimics of prostatic adenocarcinoma

Benign mimics present either as common challenges in daily routine practice or may cause diagnostic dilemmas because some are less commonly seen and one may be less familiar in recognizing them. There are a multitude of mimics of prostatic adenocarcinoma, which may represent normal gland structures, benign proliferations, atrophic lesions, hyperplastic or metaplastic changes, and inflammatory processes. Some of them are preferentially found in certain anatomic areas of the prostate, either confined to the prostate, or outside of the gland. Various benign mimics of prostatic carcinoma may be also evaluated based on their morphologic similarity to Gleason patterns 3-5 of prostatic adenocarcinoma. Most of the mimics are easily recognizable in larger specimens, such as TUR of the prostate or radical prostatectomy specimens, but they may pose diagnostic problems when the evaluation is done on limited tissue, such as needle-core biopsies or if prostate specimens are infrequently encountered in practice. Therefore, before signing out a report with a diagnosis of prostatic carcinoma, pathologists should carefully consider and rule out the various benign lesions that may mimic carcinoma. This is particularly relevant in the current prostate biopsy practice which relies on using extended biopsy core templates. The awareness and familiarity with the characteristic features of the mimics and judicial use of additional ancillary tests, including immunohistochemistry can prevent overdiagnosis and false-positive interpretation. This review provides a contemporary update on the broad spectrum of the benign prostatic lesions that can mimic prostate adenocarcinoma, outlines their key morphologic and immunohistochemical diagnostic features, and provides a diagnostic, pattern-based approach in establishing a correct diagnosis and distinguishing them reliably from prostatic adenocarcinoma.

A pitfall in transrectal prostate biopsy: malakoplakia evaluation of two cases based on the literature review

Malakoplakia is a rarely seen inflammatory condition that is considered to develop secondary to a chronic Escherichia coli infection. Although malakoplakia usually affects the genitourinary tract, it may also be observed in the colon, stomach, lungs, liver, bones, uterus, and skin. Malakoplakia of the genitourinary system usually involves the bladder, whereas it may also affect the prostate along with the bladder. Malakoplakia of the prostate is very rare, and it may be clinically mistaken for prostatic malignancies. Definitive diagnosis is only possible through histopathological examination. This study elaborates on two patients who presented to our hospital in 2013 with high PSA levels. The primary clinical consideration was prostate carcinoma. However, these two cases were diagnosed as malakoplakia based on the results of histopathological analysis of the transrectal prostate biopsy specimen.

Benign mimickers of prostatic adenocarcinoma

The diagnosis of prostatic adenocarcinoma, especially when present in small amounts, is often challenging. Before making a diagnosis of carcinoma, it is prudent for the pathologist to consider the various benign patterns and processes that can simulate prostatic adenocarcinoma. A useful method of classifying benign mimickers is in relationship to the major growth patterns depicted in the classical Gleason diagram. The four major patterns are small gland, large gland, fused gland and solid. Most mimickers fit within the small gland category and the most common ones giving rise to false-positive cancer diagnosis are atrophy, post-atrophic hyperplasia, atypical adenomatous hyperplasia and seminal vesicle-type tissue. A number of other histoanatomic structures such as Cowper's gland, verumontanum mucosal glands, mesonephric glands and paraganglionic tissue may be confused with adenocarcinoma. Additionally, metaplastic and hyperplastic processes within the prostate may be confused with adenocarcinoma. Furthermore, inflammatory processes including granulomatous prostatitis, xanthogranulomatous prostatitis and malakoplakia may simulate high-grade adenocarcinoma. Atypical adenomatous hyperplasia (adenosis), a putative precursor of transition zone adenocarcinoma, has overlapping features with low-grade adenocarcinoma and may cause problems in differential diagnosis, especially in the needle biopsy setting. The pathologist's awareness of the vast array of benign mimickers is important in the systematic approach to the diagnosis of prostatic adenocarcinoma. Knowledge of these patterns on routine microscopy coupled with the prudent use of immunohistochemistry will lead to a correct diagnosis and avert a false-positive cancer interpretation.

Combined occurrence of prostate carcinoma and malacoplakia

This is a case of a 56-year-old male patient suffering from a combination of prostate carcinoma and malacoplakia. A 56-year-old male patient was admitted in our Department because ischuria due to the enlargement of the prostate. Perineal needle biopsy was done resulting carcinoma of prostate. Radical prostatectomy was performed. Histology proved carcinoma and a great part of the enlarged prostate consisted of malacoplakia. Questions related to the morphology, tissue structure as well as diagnosis are briefly surveyed. This is the first report on the rarely occurring combination of prostate carcinoma and malacoplakia treated by radical retropubic prostatectomy.