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Prostate

Prostatic carcinoma

Core biopsies


Reviewers: Monika Roychowdhury, M.D., (see Reviewers page)
Revised: 29 July 2012, last major update July 2012
Copyright: (c) 2003-2012, PathologyOutlines.com, Inc.

General
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● “Six pack”: 6 samples from selected portions of prostate via a spring-loaded 18 gauge biopsy, has false negative rate of 12% due to sampling error; now are often 12-18 samples
● 25% of tumor bearing specimens contain only a small focus of carcinoma
● Transrectal biopsies more accurate than transperineal biopsies
● Gleason score in biopsy correlates with that in prostatectomy (same: 58%, +/- 1 unit: 92%)
● More errors occur with Gleason scores 5 or 6, which tend to underestimate prostatectomy Gleason score (Am J Surg Pathol 1997;21:566)
● Tumor seeding of needle tract is rare complication of perineal needle biopsy, more likely with poorly differentiated carcinomas, less common with transrectal biopsy
● Findings at 12-core transrectal ultrasound-guided prostate needle biopsy plus preoperative PSA predict advanced local disease at prostatectomy (Am J Clin Pathol 2012;137:739)


Core biopsy processing

General
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● Three levels recommended (Arch Pathol Lab Med 1998;122:833, Am J Clin Pathol 1997;107:26, Am J Surg Pathol 1999;23:257)
● Additional levels if atypical glands, suspicious for malignancy (Am J Clin Pathol 1998;109:416)
● Pathology review of core biopsies recommended before radical prostatectomy is performed (Am J Surg Pathol 1996;20:851)
● Biopsy is unsatisfactory if no prostatic glands or stroma; stroma only may indicate a stromal hyperplastic nodule and is satisfactory
● Average of 23% of total length of a core is missed by a single histologic level
● Preembedding cores using "stretch" method may yield more tumor/core, more cores with tumor, more cases with tumor, fewer atypical small acinar diagnoses, fewer cases with 3mm or less of Gleason 6 or less cancer (Hum Pathol 2000;31:1102)
● Epstein recommends assigning a Gleason score of at least 5 for adenocarcinoma diagnosed on core biopsies (as opposed to TURP) since 2-4 in this setting usually represent undergrading, are not reproducible and may adversely impact patient care (Am J Surg Pathol 2000;24:477)


Microscopic features of core biopsies

General
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Notes: in assessing intraluminal, amorphous eosinophilic material, must exclude decapitation secretions or fractured corpora amylacea
● Collagenous micronodules are nodular masses of paucicellular, eosinophilic, fibrillar stroma which impinge on acinar lumens (Arch Pathol Lab Med 1995;119:444)
● Glomerulations are rounded epithelial tufts within glands reminiscent of renal glomeruli; present in 5% of radical prostatectomy specimens (5-20% of each tumor) and 3% of needle biopsies with cancer (5-10% of each cancer); not observed in benign lesions (Hum Pathol 1998;29:543)

Micro description
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● Features suggestive of malignancy in a core are (malignant vs. benign specimens): prominent nucleoli (94% vs. 25%), marginated nucleoli (88% vs. 7%), multiple nucleoli (64% vs. 0%), blue-tinged mucinous secretions (52% vs. 0%), intraluminal crystalloids (41% vs. 1%), intraluminal amorphous eosinophilic material (87% vs. 2%), collagenous micronodules (2% vs. 0%), glomerulations (15% vs. 0%), perineural invasion (22% vs. 0%), retraction clefting (39% vs. 7%), and invasion of fat (1% vs. 0%) (Arch Pathol Lab Med 2002;126:554)

Micro images
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Various images


Basal cell stains on core biopsies

General
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● See also Prostatic carcinoma-immunohistochemistry
● Should be reserved for equivocal cases where conventional pathology proves to be inconclusive (Int Urol Nephrol 2010;42:325)
● High molecular weight cytokeratin (34βE12) and p63 detect basal cells, which are lacking in adenocarcinoma, and don’t stain secretory cells
● Diagnosis of prostatic adenocarcinoma with positive 34βE12 basal cell staining should be made with extreme caution, only if unequivocal cancer on H&E; when present, is usually patchy, may indicate outpouchings of high grade PIN (Am J Surg Pathol 2002;26:1151)
● Should save intervening levels for stains
● Can also destain / restain needle biopsies and put original sections on coated slides (Hum Pathol 2000;31:1155)
● Recommended to use cocktail with 34βE12 and p63 (Am J Surg Pathol 2003;27:365)
Note: A negative high molecular weight keratin is only diagnostic of adenocarcinoma if there is a high (90%) pre-test suspicion of carcinoma, must also see staining of obviously benign glands
● Positive staining can identify benign mimickers of cancer including benign crowded glands, adenosis and atrophy, and occasionally differentiate high grade PIN vs. cancer

Micro images
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34βE12 staining

   
H&E of above

   
p63 staining


P504S/AMACR stains on core biopsies

General
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● See also Stains-AMACR
● Sensitive and specific for prostate carcinoma on needle biopsies
● Recommended to use a combination of P504S and 34βE12 to diagnose limited prostatic adenocarcinoma (Am J Surg Pathol 2002;26:1169)
● Stains some hyperplastic nodules and benign glands adjacent to transition zone carcinomas (Hum Pathol 2003;34:228)
● Negative staining with P504S in suspicious foci does not necessarily indicate a benign diagnosis (Am J Surg Pathol 2002;26:1169)
● P504S/p63 can be used as a single color cocktail to distinguish prostatic cancer involvement in seminal vesicles versus cancer mimickers because of the architectural complexity of the seminal vesicles and ejaculatory ducts (Arch Pathol Lab Med 2010;134:983)


Minimal prostatic adenocarcinoma on core biopsy

General
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● Defined as <1 mm on biopsy
● Usually is pathologically significant tumor at prostatectomy
● Common features are nucleomegaly (96%), infiltrative growth pattern (88%), intraluminal secretions (78%), prominent nucleoli (64%), associated high grade PIN (40%), amphophilic cytoplasm (36%), hyperchromatic nuclei (30%), intraluminal crystalloids(22%)
● Uncommon features are perineural invasion (2%), collagenous micronodules (2%), mitotic figures (2%) (Mod Pathol 1998;11:543)

Micro images
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Various images

Differential diagnosis
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● Adenosis, atrophy, high grade PIN (Am J Clin Pathol 2000;114:896)

End of Prostate > Prostatic carcinoma > Core biopsies


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