Prostate gland & seminal vesicles

• ICD-11: GA90 - hyperplasia of prostate

• 58 - 88 year old men with clear cell cribriform hyperplasia of the prostate (Am J Clin Pathol 1991;95:446)
• 60 year old man with benign prostatic hyperplasia (Ann Int Med Den Res 2017;3:25)
• 62 - 87 year old men with clear cell cribriform hyperplasia of prostate (Am J Surg Pathol 1986;10:665)

• Focal or diffuse nodular clusters of acini with cribriform morphology
• Involved ducts follow the architectural distribution of adjacent benign prostatic hyperplasia
• Cuboidal to columnar cells with clear to pale eosinophilic granular cytoplasm and small, monotonous nuclei with inconspicuous nucleoli
• Basal cell layer is prominent and frequently discernible on light microscopic examination
• Stroma surrounding glands is cellular (benign prostatic hyperplasia-like)
• References: Am J Clin Pathol 1991;95:446, Surg Pathol Clin 2022;15:591

Contributed by Rafael E. Jimenez, M.D. and Arpan Samaddar, M.B.B.S.

• Prostate, transurethral resection:
  • Benign prostatic hyperplasia
  
  
• Note: it is not necessary to specify clear cell cribriform hyperplasia in the diagnosis as it has no clinical impact and the term may cause confusion

• Central zone histology (Hum Pathol 2002;33:518, Cancers (Basel) 2022;14:3041):
  • Central zone of the prostate near the base can have focal cribriform glands
  • Also lacks cytological atypia and inconspicuous nucleoli
• Basal cell hyperplasia (cribriform / pseudocribriform pattern) (Hum Pathol 2005;36:480, Cancers (Basel) 2022;14:3041):
  • Commonly found in the transition zone
  • Clusters of proliferating basal cells within back to back acini that are growing in a solid or cribriform pattern
  • Scant cytoplasm with hyperchromatic nuclei, rendering a basophilic appearance
  • May have prominent nucleoli
  • Positive for basal cell markers (p63, HMWCK)
• Atypical intraductal cribriform proliferation (AIDCP):
  • Loose cribriform (lumen spanning) architecture
  • Moderate cytological atypia (enlarged, hyperchromatic nuclei) and prominent nucleoli
  • Previously classified as high grade prostatic intraepithelial neoplasia with cribriform architecture
• Intraductal carcinoma:
  • Basal cells retained at the periphery of the lesion
  • Expanded acini and ducts with a dense cribriform architecture
  • Marked cytological atypia with nonfocal comedonecrosis
  • PTEN and ERG can be positive (invariably negative in clear cell cribriform hyperplasia)
• Invasive acinar adenocarcinoma with cribriform Gleason pattern 4:
  • Common in peripheral zone
  • Confluent glands in an infiltrative growth pattern without a basal cell layer
  • Nucleomegaly and prominent nucleoli
  • Negative for basal cell markers (p63, HMWCK)
• Ductal type adenocarcinoma:
  • Lacks basal cell layer
  • Large confluent glands with infiltrative papillary growth pattern, lined by columnar cells with prominent nucleoli
  • Negative for basal cell markers (p63, HMWCK)

Which of the following is true about the prostatic lesion shown above?

1. Carries a risk of progressing to high grade prostatic intraepithelial neoplasia
2. Commonly encountered in the peripheral zone
3. Considered to be an architectural variant of nodular prostatic hyperplasia
4. Cytologically atypical with prominent nucleoli

C. Considered to be an architectural variant of nodular prostatic hyperplasia. The image shows clear cell cribriform hyperplasia, which is considered to be a histological variant of benign prostatic hyperplasia. Answer B is incorrect because clear cell cribriform hyperplasia is commonly encountered in the transitional zone of the prostate. Answer D is incorrect because clear cell cribriform hyperplasia is cytologically bland with monotonous nuclei and inconspicuous nucleoli. Answer A is incorrect because clear cell cribriform hyperplasia is not a premalignant condition.

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Reference: Clear cell cribriform hyperplasia

Which of the following matches the immunohistochemical profile for clear cell cribriform hyperplasia of the prostate?

1. HMWCK-, p63-, AMACR-
2. HMWCK-, p63-, AMACR diffuse +
3. HMWCK-, p63+, AMACR-
4. HMWCK+, p63+, AMACR-
5. HMWCK+, p63+, AMACR diffuse +

D. HMWCK+, p63+, AMACR-. Acini are lined by an intact basal cell layer positive for HMWCK and p63. AMACR is usually negative but may be focally positive in some cases of this entity, a histological variant of benign prostatic hyperplasia. This immunohistochemical profile would also be seen in central zone histology and basal cell hyperplasia with a cribriform / pseudocribriform pattern. Answer E is incorrect because atypical intraductal cribriform proliferation and intraductal carcinoma will show an intact basal cell layer positive for HMWCK and p63 (may show discontinuous staining) with AMACR positivity. Answer B is incorrect because invasive acinar adenocarcinoma with cribriform Gleason pattern 4 and ductal type adenocarcinoma do not have an intact basal cell layer and will be negative for HMWCK and p63, while being positive for AMACR. Answers A and C are incorrect because these immunohistochemical profiles do not align with any other entities in the differential.

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Reference: Clear cell cribriform hyperplasia