|Year : 2015 | Volume
| Issue : 2 | Page : 147-153
Usefulness and significance of morphological criteria with regard to Gleason grade in the diagnosis of adenocarcinoma prostate
Abhishek Kumar1, Nisha J Marla1, Hilda Fernandes1, Praseena Kallingal2
1 Department of Pathology, Father Muller Medical College, Mangalore, Karnataka, India
2 Lecturer/Bio-statistician, Father Muller College of Nursing, Mangalore, Karnataka, India
|Date of Web Publication||13-Jul-2015|
Dr. Abhishek Kumar
Sector 12 F, Quarter No - 1046, Bokaro Steel City - 827 012, Jharkhand
Source of Support: None, Conflict of Interest: None
Clinical trial registration CTRI/2013/07/003821
Objectives: 1. To study Gleason grade and sum. 2. To study the morphological criteria and their significance. 3. To correlate morphological features with Gleason pattern. Materials and Methods: We studied 411 prostatic specimens, 342 benign and 69 neoplastic cases which were received over a period of two years duration at our Institution. The neoplastic cases were further categorized for occurence of the important morphological criteria with regard to Gleason Grade. Results: Out of the 69 cases of adenocarcinoma prostate, 3 cases were well differentiated adenocarcinoma (Gleason sum 2-4), 35 cases were moderately differentiated adenocarcinoma (Gleason sum 5-7) and 31 cases were poorly differentiated adenocarcinoma (Gleason Sum 8-10). Nucleomegaly was seen in 73%, prominent nucleoli in 60.8%, amphophilic cytoplasm in 19%, intraluminal crystalloids in 62%, collagen micronodules in 36%, chronic inflammation in 64%, perineural invasion in 91%, tumour infiltration was seen in 76%, retraction clefting in 66% cases and necrosis in 49% of the cases. Conclusion: Perineural invasion, Infiltrative pattern and Necrosis have significant correlation with higher Gleason Sum. Morphologically nucleomegaly, nucleolar changes, amphophilic cytoplasm and collagenous micronodules are important additional features which help in clinching the diagnosis.
Keywords: Collagenous micronodules, Gleason grade and sum, intraluminal crystalloids, perineural invasion. transrectal biopsies, transurethral resection of prostate
|How to cite this article:|
Kumar A, Marla NJ, Fernandes H, Kallingal P. Usefulness and significance of morphological criteria with regard to Gleason grade in the diagnosis of adenocarcinoma prostate. Muller J Med Sci Res 2015;6:147-53
|How to cite this URL:|
Kumar A, Marla NJ, Fernandes H, Kallingal P. Usefulness and significance of morphological criteria with regard to Gleason grade in the diagnosis of adenocarcinoma prostate. Muller J Med Sci Res [serial online] 2015 [cited 2022 Jan 25];6:147-53. Available from: https://www.mjmsr.net/text.asp?2015/6/2/147/160690
| Introduction|| |
Prostatic adenocarcinoma is the sixth most common carcinoma worldwide and third most common in the males.  In the recent years there has been an explosive increase in the number of prostatic transrectal needle biopsies and transurethral resections due to increased life expectancy, increased awareness and early need for diagnosis.  While Transrectal needle biopsies aim at diagnosis, Transurethral Resection of Prostate (TURP) is done for both diagnostic and therapeutic indications.
As a pathologist diagnosis of prostatic adenocarcinoma is often a diagnostic dilemma when biopsy bits are small or TURP bits are few with only few clusters of atypical glands. Hence several diagnostic morphological criteria have been proposed for accurate diagnosis. ,,,, Three major histological criteria are Infiltrative growth pattern, presence of Macronucleoli and absence of Basal cell layer.  Perineural invasion has been a time honoured morphological criteria. ,, Relatively little information is available regarding these morphological features within needle biopsies. 
In this study, we intend to study the frequency with which these morphological criteria occurred, correlate it with the Gleason sum. The diagnostic criteria which were included are nuclear and nucleolar changes, cytoplasmic changes, intraluminal crystalloids, perineural invasion, inflammation, collagen micronodules, necrosis, tumour infiltration pattern and retraction clefts. ,,,,
| Materials and Methods|| |
The current study was conducted in the Department of Pathology, Father Muller Medical College, Mangalore, Karnataka, India for a period of two years (2011-12). A total of 411 prostatic specimens comprising of Transrectal prostatic biopsies and TURP specimens were received. Out of 411 cases received during the specified time period, 69 cases were diagnosed as adenocarcinoma of Prostate. Each of these 69 cases were then cross evaluated for presence or absence of the above mentioned morphological criteria. For statistical purpose these morphological criteria were evaluated along with the Gleason sum and individual incidences of each criteria for different values of the Gleason sum was evaluated. The tissue sections were routinely processed with 10% buffered formalin, parafiin embedded, cut into 4 μm thick sections and stained by standard hematoxylin-eosin stain.
Each case was analysed for Gleason grade and assigned a Gleason sum. Simultaneously each case was evaluated for all above mentioned morphological criteria. To identify nucleomegaly tumour cells were compared with cells within the surrounding benign glands. Prominent nucleoli were identified by viewing nucleoli within the nuclei at low power (10x). Cytoplasmic staining was categorized as amphophilic or eosinophilic. Intraluminal crystalloids were differentiated from corpora amylacea and secretions. Collagenous micronodules were recognized as nodular masses of paucicellular, eosinophilic, fibrillar stroma, which is impinged on acinar lumen. Retraction clefts were identified as separation of acini from adjacent stroma. Perineural invasion was identified as circumferential or intraneural invasion by tumour cells. Comedo pattern of necrosis within tumour aggregates were identified. Infiltrative pattern in the form of medium sized glands, small glands, cribriform glands and individual cell were noted and graded into Gleason pattern accordingly.  No specialized technique morphometry or special stains were employed. 
Comparision between groups were made with χ2 test.
| Results|| |
Out of 69 carcinoma cases 32 cases were TURP specimen whereas 37 were transrectal biopsies. The age of the patients ranged from 50-85 years. A total of 411 cases of prostatic lesions were received out of which 69 were diagnosed with carcinoma Prostate, 16 cases were of Prostatic Intraepithelial Neoplasia (PIN), 43 cases of hyperplasia with adenoid or leiomyomatous components and few showing co-existing prostatitis. Most of the cases showed Nodular Hyperplasia of Prostate, both as primary pathology as well as concurrent pathology. Each case of adenocarcinoma Prostate was evaluated for Gleason grade and above mentioned morphological criteria.  Their incidences with respect to Gleason sum was calculated. Gleason grading was done on basis of the [Table 1].  [Table 2] shows incidence rates of the above mentioned morphological criteria for defined range of Gleason sum. [Table 3] shows the distribution of cases with respect to the Gleason sum. [Table 4] shows comparisions with previous studies and the P-value for each criterion.
|Table 2: Incidence of morphological criteria with respect to Gleason sum|
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| Discussion|| |
Carcinoma Prostate is the sixth most common carcinoma worldwide and third most common cancer in male population. Benign Prostatic Hyperplasia (Nodular Hyperplasia of Prostate) along with carcinoma Prostate accounts for 90% of the prostatic diseases. Morbidity rates are much higher than mortality rates in Carcinoma Prostate. Hence prevalence of the disease in general is very high and is often overlooked until clinical symptoms arise. Across the globe, the prevalence rates vary with geographical location and population demography i.e. age and ethnicity. Men below 50 years have lower incidences of developing carcinoma compared to men above 50 years. With increasing age the incidence rates increase exponentially. Similarly incidence rates are highest in Blacks followed by Whites and Asians. 
Various diagnostic modalities have been introduced for early and reliable diagnosis of prostatic diseases as Benign or Malignant. They include biochemical parameters like Prostate Specific Antigen (PSA), Prostatic acid Phosphatase (PAP), PSA density and PSA velocity. Clinically DRA (Digital rectal examination) and radiologically Transrectal Ultrasonography is proven useful for diagnosis of early carcinoma Prostate. 
Histopathologically TURP and Transrectal Biopsies were evaluated for the presence of features of carcinoma.  Gleason Grade and Gleason sum [Table 1] have proved a valuable tool in staging and stratifying the disease and hence deciding its treatment modalities and prognosis. But Gleason grade and sum are particularly difficult to do on transrectal biopsies or inadequate TURP specimens. But according to recent guidelines set by College of American Pathologists (CAP) it is now mandatory to assign a Gleason Grade and give a sum on biopsies.
Gleason Grade and Sum, since their introduction in 1993, have been used by pathologists to grade adenocarcinoma of Prostate and prognosticate its treatment.  It is based on glandular architecture only. Nuclear atypia and cytoplasmic changes are not evaluated. , Difficulties arise in situations like differentiating between a well differentiated adenocarcinoma from benign and atypical small glandular proliferation or differentiating poorly differentiated adenocarcinoma from inflammatory processes or metastatic carcinoma and finding tumour glands in small biopsies. 
Histopathological study of needle biopsies of Prostate and TURP specimens is the gold standard for the diagnosis of adenocarcinoma of the Prostate. ,,,,, The histological diagnosis is based on microscopic criteria. Since biopsies may be inadequate or insufficient to report with confidence based on the glandular architecture alone, several other morphological criteria have proved to be useful in making conclusive diagnosis [Table 2] and [Table 4]. Nuclear enlargement has been the most constant criterion as it is easily detectable and reproducible finding. It can be attributed to the fact that comparision with adjacent benign glands can be made. ,,,, Nucleolar enlargement [Figure 1] and [Figure 2] is another frequent though not constant finding and was advocated by Totten et al.  In current study 53% of cases showed enlarged vesicular nuclei and 69% had prominent nucleoli. Epstein in his study on limited adenocarcinoma observed 76% cases with nucleomegaly and prominent nucleoli.  In a study by Iczkowski and Bostwick  prominent nucleoli were seen in 100% malignant cases and 55% of atypical small acinar proliferation. Studies by Leroy et al. and Epstein showed amphophilic cytoplasm in 39% and 33% cases respectively. , In our study amphophilic cytoplasm [Figure 3] and [Figure 4] was seen in 19% of the cases. Intraluminal crystalloids are amorphous, eosinophilic crystalloids; recently recognized in Prostate carcinoma specimens. It is unclear whether they are true secretions or precursors for crystal formation or individual cell necrosis. These secretions must be carefully differentiated from decapitated secretions or fractured corpora amylacea in benign glands. ,,,,,,,,, Varma et al. observed intraluminal crystalloids in 86.7% of malignant cases and in only 2% of benign cases. Epstein noticed them in 60% of TURP specimens and 10-23% of biopsies. In our study we got an incidence rate of 62% similar to study by Leroy et al. [Figure 5] and [Figure 6]. Chronic inflammation comprising of lymphocytes was observed in 64% of the cases [Figure 7] and [Figure 8] while other showed minimal inflammation. This finding is not well documented in literature. Collagenous micronodules are microscopic nodular aggregates of paucicellular eosinophilic fibrillar stroma. ,,,,,,,,,, It is reported to be specific but infrequent diagnostic clue. This finding was reported less frequently in studies by Bostwick et al.  (0.6% in biopsies, 12.7% in radical prostatectomies), Varma et al. (2%) and Leroy et al. (4%). However our study showed incidence rate of collagenous micronodules to be 36%. Baisden et al. in their study concluded that collagenous micronodules are rarely key features for the diagnosis of limited adenocarcinoma.  However collagenous micronodules are not reported in benign glands, nodular hyperplasia of Prostate or prostatic intraepithelial neoplasia. Halpert et al. in an autopsy study described retraction clefts around the malignant glands.  Varma et al. found this in concordance with his pilot study (40%). The mechanism of clefting is unknown. While some workers believe it to be due to basement membrane abnormality others are of view that it is due to overexpression of collagenases and other enzymes. Clefting has to be differentiated from artifactual clefting in the tumour glands and tumour emboli. ,,,,, In our study 66% of the cases showed retraction clefts. Perineural invasion has been a hallmark for the diagnosis of prostatic adenocarcinoma. Circumferential and intraneural invasion are pathognomic of carcinoma. ,,,,, Previous studies by Epstein reports perineural invasion in 20% of the cases, Leroy et al. 0% of the cases, Varma et al. in 22% of the cases and Bastacky et al.  in 22% cases. Our study however showed much higher perineural invasion rate of 91% [Figure 9] and [Figure 10].
Comedonecrosis within tumour glands has been described in literature earlier but their incidences have not been reported. ,,,,, In present study we found incidence of necrosis to be 49% [Figure 11] and [Figure 12]. Infiltrative pattern comprising predominantly of cribriform glands [Figure 13] and small individual glands [Figure 14] were the commonest pattern in our study. ,,,,, Moderately and poorly differentiated adenocarcinoma comprised of 95% of the cases. This is in concordance with study by Thorson et al.,  where he found infiltrative pattern of greater than grade 4 in 82% of the cases.
| Conclusion|| |
In architecturally atypical foci where infiltration pattern cannot be determined one should look for alternate morphological criteria to determine the malignancy. Pathologists everywhere are being confronted with situation where they have to give a confident diagnosis on scant biopsies or inadequate specimens. They are expected to grade the tumour and give Gleason sum. Thus a set of well established morphological criteria along with Gleason Grade would aid in making sound diagnosis. Features like nucleomegaly with prominent nucleoli, amphophilic cytoplasm have been very specific and in previous studies been proved significant. Intraluminal crystalloids have shown an inverse correlation with malignancy. Perineural invasion has been hallmark in making diagnosis. Necrosis and infiltration pattern were significant findings in our study. In conclusion diagnosis of prostatic adenocarcinoma on biopsies and TURP should be based on cumulative knowledge of the Gleason Grade and the constellation of morphological criteria.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12], [Figure 13], [Figure 14]
[Table 1], [Table 2], [Table 3], [Table 4]