Microscopic description:

Numerous cribriform glands arranged in a nodular fashion with variable intervening stroma

Epithelial cells have a distinctive clear cytoplasm and small nuclei with inconspicuous or small nucleoli

Basal cells may be invisible in some glands, very prominent in others or form small knots to the side

IHC performed to evaluate atypical glands: positive p63, CK5; negative AMACR 

Discussion:

Considered a cribriform histologic variant of benign hyperplasia of prostate (BPH)

Mostly in TURP specimens of men with lower urinary tract obstruction secondary to BPH

Most commonly involves transitional zone of prostate

It is NOT a risk factor for prostate cancer

Grossly it resembles BPH. On cross section, there is nodular expansion of periurethral area with compression of posterior lobes and urethra

IHC for high molecular weight cytokeratin highlights the basal cells, supporting a benign diagnosis

Flow cytometric studies performed on 13 cases of cribriform clear cell hyperplasia showed diploid DNA in all cases

Differential diagnosis:

Adenocarcinoma of prostate, Gleason score 4+4=8 (due to cribriform pattern)

  • The bland cytology and presence of basal cells in some glands in cribriform clear cell hyperplasia rules out carcinoma

High grade PIN

  • Clear cribriform hyperplasia may show basal cells with nucleoli while the luminal cells have small nuclei without nucleoli
  • In contrast, the luminal cells of high-grade PIN show prominent nucleoli

References:

Frauenhoffer, E. E., Ro, J. Y., el-Naggar, A. K., Ordóñez, N. G., & Ayala, A. G. (1991). Clear cell cribriform hyperplasia of the prostate. Immunohistochemical and DNA flow cytometric study. American journal of clinical pathology, 95(4), 446–453. https://doi.org/10.1093/ajcp/95.4.446

Ayala, A. G., Srigley, J. R., Ro, J. Y., Abdul-Karim, F. W., & Johnson, D. E. (1986). Clear cell cribriform hyperplasia of prostate. Report of 10 cases. The American journal of surgical pathology, 10(10), 665–671. https://doi.org/10.1097/00000478-198610000-00001

Hameed, O., & Humphrey, P. A. (2010). Pseudoneoplastic mimics of prostate and bladder carcinomas. Archives of pathology & laboratory medicine, 134(3), 427–443. https://doi.org/10.5858/134.3.427

CASE IMAGES