Sclerosing adenosis of the prostate. Histologic features in needle biopsy specimens

Sclerosing Adenosis of the Prostate-A Benign Lesion Similar to Prostate Cancer: A Case Report and Literature Review

Sclerosing adenosis of the prostate (SAP) is a rare benign non-neoplastic small acinar hyperplasia. Like sclerosing adenosis of the breast, which is confused with breast cancer, SAP is a trap in the pathological differential diagnosis of benign and malignant lesions of the prostate. We report such a case to help colleagues better distinguish and diagnose such diseases. A 75-year-old patient with SAP had a prostate specific antigen (PSA) level of 11.0 ng/mL, and he had been suffering from progressive dysuria for 3 years. The central glandular area and the right periphery of the prostate were found to have nodular low signals on magnetic resonance imaging (MRI). Prostate biopsy showed that basal cells were positive for P63 and P504s, few basal cells were positive for S-100, and the positive rate of Ki67 was approximately 2%. We consider that the possibility of SAP is high. The patient was treated conservatively and was discharged in good health, free of dysuria and other problems. SAP is a rare benign lesion that is easily misdiagnosed as prostate cancer. The prostatic gland tube has a complete basal cell layer surrounding it, as well as myoepithelial cell metaplasia of basal cells, which is a key trait in distinguishing it from prostate cancer. Although the latest research indicates that SAP does not require treatment, the question of whether it is a risk factor for prostate cancer remains unanswered.

Prostate sclerosing adenopathy: A clinicopathological and immunohistochemical study of twelve patients

BACKGROUND

Although sclerosing adenopathy of the prostate is a very rare benign disease, an effective differential diagnosis is required. Here, we report the clinicopathological and immunohistochemical morphological features of 12 cases of sclerosing adenopathy of the prostate to improve understanding of the disease.

AIM

To investigate the clinicopathological features, diagnosis, and immunohistochemical phenotypes that distinguish prostate sclerosing adenopathy from other conditions.

METHODS

The clinical data, laboratory tests, pathological morphology, and immunohistochemical phenotypes of 12 cases of prostatic sclerosing adenopathy were retrospectively analyzed, and the relevant literature was reviewed.

RESULTS

All patients were elderly men (mean age, 71.7 years; 62–83 years). Eleven of them had hematuria, urinary frequency, urinary urgency, difficulty in urination, and serum total prostate-specific antigen values within the normal range. One patient had increased blood pressure. Enlarged prostates with single to multiple calcifying foci were observed. Moreover, prostate tissue hyperplastic changes were observed in all patients. Small follicular hyperplastic nodules without an obvious envelope, with a growth pattern mimicking the infiltration pattern of "prostate adenocarcinoma" were noted. Basal cells expressed AR, CKH, P63, and CK5/6, and myoepithelial markers, such as calponin, S100, and smooth muscle actin. No recurrence or exacerbation of the lesions was observed, except for one case of death due to bladder cancer.

CONCLUSION

Prostatic sclerosing adenopathy is highly misdiagnosed as prostate adenocarcinoma or other tumor-like lesions. Therefore, it should attract the attention of clinicopathologic researchers.

68Ga-PSMA-11 PET/MR Can Be False Positive in Normal Prostatic Tissue

Prostate-specific membrane antigen (PSMA) is a transmembrane glycoprotein expressed in the cytosol of normal prostate tissue and highly overexpressed on the membrane of prostate cancer, therefore increasingly used to image prostate cancer. We report a case of a 65-year-old man with two focal PSMA-positive areas on a Ga-PSMA-11 PET/MR, one corresponding to a prostate carcinoma (Gleason score 4 + 3) and another region without any evidence of malignancy, but with corresponding high PSMA-expression on immunohistochemistry.

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.

Atypical Adenomatous Hyperplasia (Adenosis) of the Prostate: DNA Ploidy Analysis and Immunophenotype

Atypical adenomatous hyperplasia (AAH) of the prostate is a microscopic proliferation of small acini that may be mistaken for adenocarcinoma. Although some data suggest that AAH is associated with adenocarcinoma arising in the transition zone, the clinical significance of this lesion is uncertain. Therefore we studied the DNA ploidy pattern and immunophenotype of AAH as compared with nodular hyperplasia and well-differentiated adenocarcinoma in 23 formalin-fixed, paraffin-embedded, whole-mounted retropubic prostatectomies. Representative sections were immunostained for keratin 34β-E12, chromogranin, bcl-2, c-erbB-2, ki67-MIB1, and factor VIII (microvessel density). DNA ploidy was determined by image analysis and Feul gen-stained sections. There were rare scattered immunoreactive cells for chromogranin, bcl-2, and c-erbB-2 in nodular hyperplasia and AAH (mainly in the basal cell compartment) and in carcinoma. The ki67-MIB1 labeling index was different between nodular hyperplasia and AAH (p<0.001) and carcinoma (p=0.003) but not between AAH and carcinoma (p=0.203). Microvessel density was different between AAH and carcinoma (p=0.001) but not between nodular hyperplasia and AAH (p=0.105) or carcinoma (p=0.0820). All foci of nodular hyperplasia, AAH, and carcinoma were diploid. Ploidy status and our selected panel of antibodies did not discriminate among these 3 entities reliably.

A prostate fibromyxoid sarcoma with smooth muscle differentiation in a F344xBNF1 rat

This report describes a spontaneous prostate fibromyxoid sarcoma with smooth muscle differentiation in an approximately 136-week-old intact male F344xBNF1 rat on a diet study for 2 weeks. At necropsy, the prostate was markedly distorted and enlarged by a firm white multinodular mass (6.0 × 4.5 × 3.5 cm). Histopathologically, the mass consisted of solid sheets of interlacing mesenchymal spindle cells with indistinct cell borders. Nuclei were separated by variable amounts of hyaline to fibrillar eosinophilic and/or myxomatous material. The extracellular myxomatous material tended to form whorls and stained positively with alcian blue. The mass stained strongly with Masson trichrome and vimentin throughout. Approximately 5% of the neoplastic cells were positive for smooth muscle actin, and none stained for desmin and pancytokeratin. To the authors' knowledge, this fibromyxoid sarcoma with smooth muscle differentiation is the first such described prostatic sarcoma in a rat.

Hybrid sclerosing adenosis and basal cell hyperplasia of the prostate

Hybrid sclerosing adenosis and basal cell hyperplasia of the prostate is a rare lesion. Here we report the seventh case of such lesions. Histological examination of the transurethral resection of the prostate of a 83-year-old Japanese man showed a small lesion consisted of sclerosing adenosis and basal cell hyperplasia, in addition to the diffuse glandular and fibromuscular hyperplasia. Immunohistochemically, many basal cells in sclerosing adenosis and basal cell hyperplasia areas showed a positive reaction for p63, cytokeratin 5, and D2-40. Additionally, many basal cells in the sclerosing adenosis area and some basal cells in the basal cell hyperplasia area were positive for S-100 protein and alpha-smooth muscle actin, which are myoepithelial cell markers. Finally, we suggest that hybrid sclerosing adenosis and basal cell hyperplasia may be actually a special form of hyperplastic lesion of all components of prostatic tissue, reflecting the unbalanced distribution of glandular, stromal (sclerosing adenosis), and basal cell hyperplasia with the differentiation toward myoepithelial cells predominantly occurring in a sclerosing adenosis area. Additionally, this case showed that D2-40 is a useful marker of basal cells.

Pseudoneoplastic mimics of prostate and bladder carcinomas

CONTEXT

The differential diagnoses of prostatic carcinoma and bladder epithelial neoplasms include several histologic mimics that should be known to avoid misdiagnosis.

OBJECTIVE

To discuss pseudoneoplastic lesions of the prostate and bladder that could potentially be confused with prostatic carcinoma and bladder epithelial neoplasms, respectively, with specific focus on their distinguishing histopathologic features.

DATA SOURCES

Relevant published literature and authors' experience.

CONCLUSIONS

Pseudoneoplastic lesions in the prostate include those of prostatic epithelial origin, the most common being atrophy, adenosis (atypical adenomatous hyperplasia), basal cell hyperplasia, and crowded benign glands, as well as those of nonprostatic origin, such as seminal vesicle epithelium. Such lesions often mimic lower-grade prostatic adenocarcinoma, whereas others, such as clear cell cribriform hyperplasia and granulomatous prostatitis, for example, are in the differential diagnosis of Gleason adenocarcinoma, Gleason grade 4 or 5. Pseudoneoplastic lesions of the urinary bladder include lesions that could potentially be confused with urothelial carcinoma in situ, such as reactive urothelial atypia, and others, such as polypoid/papillary cystitis, where papillary urothelial neoplasms are the main differential diagnostic concern. Several lesions can mimic invasive urothelial carcinoma, including pseudocarcinomatous hyperplasia, von Brunn nests, and nephrogenic adenoma. Diagnostic awareness of the salient histomorphologic and relevant immunohistochemical features of these prostatic and urinary bladder pseudoneoplasms is critical to avoid rendering false-positive diagnoses of malignancy.

Benign Mimickers of Prostate Adenocarcinoma on Needle Biopsy and Transurethral Resection

Prostate needle biopsy currently is the gold standard method for the diagnosis, management, and prognosis of prostate cancer. Obtaining an accurate diagnosis is crucial for pursuing proper patient management. This article discusses histologic mimickers of prostate carcinoma highlighting microscopic features that are helpful to reach a correct diagnosis and emphasizing potential diagnostic pitfalls.

Pitfalls in the diagnosis of prostatic cancer: retrospective review of 1791 cases with clinical outcome

AIMS

To assess the possible reasons for error in the diagnosis of prostatic cancer with available follow-up data.

METHOD AND RESULTS

A cohort of 1791 cases of prostatic cancer diagnosed in the UK between 1990 and 1996 was examined. All cases were clinically localized at presentation, treated by non-curative methods and detailed follow-up was available. A panel of genitourinary pathologists reviewed the pathology of all cases. One hundred and thirty-three (7.5%) of cases were reassigned to a non-malignant diagnosis. Where possible, reasons for the initial diagnosis were given. These included severe atrophy, inflammatory induced atypia, sclerosing adenosis, atypical adenomatous hyperplasia and basal cell hyperplasia. Follow-up of these patients showed an extremely low death rate from prostatic cancer: lower than that for the Gleason combined score of five or less tumours diagnosed in this series.

CONCLUSIONS

Many morphological entities potentially mimic prostatic cancer and may be responsible for misdiagnosis in routine specimens. Continuing education in prostatic morphology and immunohistochemistry may have helped reduce this error rate.