Minimal focus of adenocarcinoma on prostate biopsy: clinicopathological correlations

Diagnostic Performance of Ex Vivo Fluorescence Confocal Microscopy in the Assessment of Diagnostic Biopsies of the Prostate

Simple Summary

Fluorescence confocal microscopy (FCM) is a novel micro-imaging technique providing optical sections of examined tissue. In this study, we compare intraoperative diagnoses from the real-time application of FCM in pre-therapeutic prostate biopsies with the final diagnoses from conventional histology. We found FCM to be an effective tool for the timely assessment of prostate biopsies enabling reliable real-time diagnosis of prostate cancer in patients requiring therapy.

Abstract

Background: Fluorescence confocal microscopy (FCM) is a novel micro-imaging technique providing optical sections of examined tissue. The method has been well established for the diagnosis of tumors in dermatological specimens. Methods: We compare intraoperative diagnoses of the real-time application of FCM in pre-therapeutic prostate biopsies (35 patients, total number of biopsy specimens: n = 438) with the findings of conventional histology. Results: Prostate carcinoma was reliably diagnosed in all patients. Depending on scan quality and experience of the examiner, smaller lesions of well differentiated carcinoma (ISUP1) could not be consistently differentiated from reactive changes. Furthermore, in some cases there was difficulty to distinguish ISUP grade 2 from ISUP grade 1 tumors. ISUP grades 3–5 were reliably detected in FCM. Conclusions: Despite some limitations, FCM seems to be an effective tool for the timely assessment of prostate biopsies enabling reliable diagnosis of prostate cancer in patients requiring therapy.

Atrophic and Microcystic Limited Prostatic Adenocarcinomas

Atrophic carcinoma and microcystic carcinoma have previously been classified as variants of conventional acinar adenocarcinoma. In this article, we studied 4 cases of atrophic carcinoma and 4 cases of limited microcystic carcinoma. We found an incidence of 0.8% in 250 needle prostatic biopsies and 1.3% of atrophic carcinoma in 150 radical prostatectomies. Microcystic carcinomas were found in 3 prostatectomies (1.2%) and in 1 needle biopsy (0.67%). The useful histological criteria for atrophic carcinoma included the irregular disposition of the glands, infiltrative pattern, "rigid" luminal borders, and intraluminal secretions. Cytological changes included scant cytoplasm, nucleomegaly, hyperchromatic nuclei, and visible nucleoli. The glands of the microcystic carcinoma differ from the benign glands because the malignant ones show a markedly greater dilatation and exhibit rigidity of glandular lumens. In some cases of microcystic carcinoma, the nuclei were flattened, small, and hyperchromatic; therefore, they can be difficult to recognize as malignant.

Prostate cancer: diagnostic criteria and role of immunohistochemistry

The diagnosis of prostate cancer is based on microscopic criteria. Presently, prostate needle biopsy interpretation can be a challenge for the pathologist due to the increased number of specimens with limited amount of suspicious glands and minimal atypia. It is critical for the pathologist to have an organized methodical approach when considering the morphological features enabling a definitive diagnosis of prostate cancer. Although several diagnostic criteria and supportive features have been advocated, only few findings are absolutely specific and diagnostic of prostate cancer. The diagnosis of prostate cancer relies on a combination of architectural and cytological features that are reviewed in detail herein. Infiltrative growth pattern, prominent nucleoli and lack of basal cells are the most useful diagnostic criteria. Perineural invasion, glomerulation and mucinous fibroplasia are pathognomonic features of prostate cancer, although uncommon on small prostate cancer foci. The role of immunohistochemistry in establishing a diagnosis of limited prostate is addressed.

Minimal (Limited) Pseudohyperplastic Prostatic Adenocarcinoma in Needle Prostatic Biopsy

Background. Study of minimum adenocarcinoma has been done almost exclusively on conventional acinar adenocarcinoma. Pseudohyperplastic adenocarcinoma can be confused with benign lesions because of its well-differentiated appearance and has not been studied when the biopsy shows few malignant glands (limited carcinoma). Methods. We reviewed 94 pseudohyperplastic adenocarcinomas diagnosed in prostatic biopsies for a period of 12 years and selected those measuring less than 1 mm or involving less than 5% of the biopsied tissue. We also reviewed 200 consecutive consultations. Results. Four (4.2%) of the 94 cases were limited pseudohyperplastic adenocarcinomas, and 3 were from consultations. Three of them were mistaken for hyperplastic nodules, prostatic adenosis, or prostatic intraepithelial neoplasm. The number of glands varied between 6 and 50 (average 23). Three nodular histological patterns were identified—nodular, adenosis-like, and pseudohyperplastic carcinoma resembling prostatic intraepithelial neoplasia. The diagnosis of adenocarcinoma was not related to the number of neoplastic glands. Histological criteria that were useful included: crowded medium to large glands, papillary infoldings, branching glands, straight luminal borders, hyperchromatic nuclei, nucleomegaly, and apparent nucleoli. Areas of transition to conventional acinar adenocarcinoma were useful in recognizing four of these neoplasms, but were barely apparent in 2 of them. Hyperchromatic nuclei were found in all cases, whereas apparent nucleoli and nucleomegaly were only present in 4. Conclusions. The architectural and cytological criteria for limited acinar adenocarcinoma are only partially useful in interpreting minimum pseudohyperplastic adenocarcinomas. Knowledge of the criteria for malignancy in both neoplasms is important in order to avoid underdiagnosis of malignancy.

Single foci prostate cancer: current diagnosis and management

Diagnosis of small prostate cancer foci is a real challenge for pathologists and urologists as it carries the risk of false positive or negative diagnosis with clinical consequences. Diagnosis of small prostate cancer foci requires a strict methodological approach which includes a search for major and minor features under low and high magnification. Ambiguous cases can be further clarified with the use of basal cell immunomarkers complemented by a positive indicator of malignancy. Despite the new diagnostic armamentarium, a few cases will continue to remain doubtful and might require an appropriate rebiopsy.

[Utility of seriated sections in prostate biopsies]

INTRODUCTION

With the routine use of prostate specific antigen, focal carcinomas and atypical small acini proliferation (ASAP) are currently detected more frequently. The number of sections per cylinder needed to detect most of them is still unknown.

METHODS

We reviewed 250 sextant prostate biopsies in the 2008-2011 period. The average number of cylinders per biopsy was 14. In each case, in addition to the original sections with three histological levels, three more sections were performed with three levels (total: 12 levels). Biopsies with focal lesion were analyzed immunohistochemically. The frequency of focal lesions was compared to a previous study of 1000 biopsies in which a single section was made with three histological levels. The main clinical and laboratory data were recorded.

RESULTS

There were 16 focal lesions (6.4%). Seven (2.8%) corresponded to focal carcinomas and nine (3.6%) to atypical proliferation. In the previous study, thirteen (1.3%) focal carcinomas and 29 (2.9%) cases with atypical proliferation were found.

CONCLUSIONS

There was an increase of 4.2% to 6.4% of focal lesions carcinomas increased from 1.3% to 2.8%. Making additional sections in all biopsies may have practical drawbacks. However, they could be performed in patients with high clinical suspicion of carcinoma (especially in young patients), or when there is a history of atypical glandular proliferations consistent with carcinoma in previous biopsies.

Minimal or No Residual Prostatic Adenocarcinoma on Radical Prostatectomy: A 5-Year Experience With “Vanishing Carcinoma Phenomenon”

Context.—“Vanishing carcinoma phenomenon” (VC) has been defined as the finding of minute or no cancer on radical prostatectomy specimens after a positive biopsy.

Objective.—To discuss our experience with VC and to recommend guidelines for its detection.

Design.—One thousand seven hundred forty-one radical prostatectomy specimens (2004–2009) processed by whole-mount section procedure yielded 21 (1.2%) cases with VC and 6 (0.34%) cases with minimal carcinoma (≤2 mm) in the radical prostatectomy specimen. To find the eluding carcinoma in VC cases or more carcinoma in minimal carcinoma cases, the following was done: 3 levels of all the paraffin blocks were obtained; if negative, the paraffin blocks were melted, the tissue was flipped, and 3 levels were prepared. The tumor bank frozen tissue was also processed for routine examination.

Results.—Three deeper levels in the radical prostatectomy specimen of 21 VC cases failed to show malignancy; however, the flipping and recutting of the tissue yielded a focus of carcinoma (1–5 mm) in 16 of 21 cases and in 3 of 16 cases in the saved frozen tissue. In 1 of the 6 cases with minimal carcinoma, subsequent recuts of the flipped tissue displayed carcinoma (2 foci of tumor, <1 mm each).

Conclusions.—In VC we recommend: embed and process any remaining prostatic tissue including any saved fresh-frozen tissue; obtain 3 levels of each paraffin block; if results are negative, melt and flip the tissue and obtain 3 more levels. Following the above guidelines, a hidden carcinoma may be detected in the majority of the cases of VC.

Periacinar Clefting and p63 Immunostaining in Prostatic Intraepithelial Neoplasia and Prostatic Carcinoma

The aim of the present study was to correlate the presence and extent of retraction clefting and the expression of p63 in neoplastic glands and glands with prostatic intraepithelial neoplasia (PIN) in needle core biopsies. We analyzed needle core biopsies from 28 patients with PIN and 41 patients with adenocarcinoma. Neoplastic glands and those with PIN were analyzed on high power field (400x) and classified in three groups according to the extent of clefting. Immunohistochemical staining was performed following Microwave Streptavidin ImmunoPeroxidase (MSIP) protocol on DAKO TechMate Horizon automated immunostainer. Periacinar retraction clefting was significantly more prominent in prostatic carcinoma compared to PIN (p<0.0001) and nonneoplastic glands (p<0.0001). There was no difference between normal glands and PIN regarding clefting (p=0.8064). p63 was positive around the whole circumference in 12 out of 28 cases with PIN, and discontinuously positive in remaining 16 PIN cases suggesting initial disruption of the basal cell layer. p63 immunostaining was also positive in all nonneoplastic glands, and negative in all carcinomas. We conclude that retraction clefting was associated with cancer and lack of basal cells, but not with PIN. The relationship between clefting and p63 immunostaining in prostatic cancer should be further analyzed.

[Minimal prostatic adenocarcinomas in the biopsy treated with radical prostatectomy]

FUNDAMENTALS

Valuation about clinical pathologyc facts of patients having undergone a radical prostatectomy due to a minimal prostate adenocarcinoma shown at the biopsy.

METHODS

Retrospective analysis of patients having undergone a radical prostatectomy due to a minimal prostate adenocarcinoma shown at the biopsy in front of the remaining radical prostatectomies.

RESULTS

In 20 patients (7.6%) out of the 260 having undergone a radical prostatectomy between 1992 and 2004 the biopsy was informed as "minimal adenocarcinoma". These patients ranged 58 to 73 years with PSA levels from 5.2 to 17.1 ng/ml. Everyone except one were clinically T1c. At the definitive pathological study the Gleason was 6, 4, 3 and 2 in 3, 3, 8 and 4 patients respectively, with one having a minimal adenocarcinoma not graded and another one with a PIN ?. 3 showed only 1 focus with a tumoral volume less than 5% of the tissue (84.2% with significant tumor or multifocal). The final staging was 1 pT0 (PIN ?), 7 pT2a, 11 pT2b and 1 pT3a (62.5% bilaterals). Relating to the remaining patients under prostatectomy, patients with minimal adenocarcinoma presented significative differences in Gleason sum (p < 0.029) and staging (p = 0.02); no in PSA mean (p = 0.243).

SUMMARY

Minimal adenocarcinomas of the prostate at the biopsy are significant but do present lower staging and grading in relation with the rest of patients.

Little or No Residual Prostate Cancer at Radical Prostatectomy: Vanishing Cancer or Switched Specimen?

With more vigilant screening for prostate cancer, there has been an associated increase in patients with little or no residual cancer at radical prostatectomy after an initial diagnosis of minute cancer on needle biopsy. This raises a critical question as to whether the biopsy and subsequent radical prostatectomy in these patients are from the same patient. We used PCR-based microsatellite marker analysis to perform identity test in 46 men (35 with minute cancer and 11 with no residual cancer). Of them, 41 were interpretable, including 31 with minute cancer and 10 with no residual cancer. All 31 interpretable cases with minute cancer showed match between the initial biopsy and radical prostatectomy specimens. Nine of the 10 interpretable cases with no residual cancer showed match and 1 showed mismatch. The remaining 5 cases (4 with minute cancer and 1 with no residual cancer) were considered uninterpretable due to technical problems. The initial biopsy of the mismatched case had high-grade cancer (Gleason score 4 + 4 = 8) measuring 9.6 mm in length with perineural invasion. Our results confirm that, in most cases of "vanishing cancer" in radical prostatectomy specimens, it reflects a chance sampling of a minute cancer and not a switch in specimens. However, specimen switch can rarely occur, and if there is high grade or a lot of cancer on the biopsy with no or very minimal cancer in the radical prostatectomy specimen, one should evaluate for patient identity.

Proliferative lesions of prostate: a multivariate approach to differential diagnosis

Prostatic needle biopsies from 142 patients were studied: 61 cases were "benign", 19 atypical small acinar proliferation, 31 high-grade prostatic intraepithelial neoplasia, and 31 adenocarcinoma. Using univariate analysis of 46 previously described morphological features, 16 variables were selected, which were followed by multivariate discriminant analysis. Of these parameters, seven (glandular fusion, crystalloids, nucleolomegaly, papillary architecture, visibility of basal cell layer, areas of normal luminal cell nucleus/cytoplasm ratio and areas of high luminal cell nucleus/cytoplasm ratio) remained significant in discriminating the groups. Multivariate analysis selected a small panel of histological features as those most helpful in the differential diagnosis of proliferative lesions in prostate biopsies.