Case of the Week

2019-30 / SEPTEMBER 9 (CONTRIBUTOR: SOUNAK GUPTA)

CASE HISTORY

A 78-year-old male underwent a transurethral resection of the prostate and representative images are shown.

The immunophenotype is as follows:

Positive: CK7 & focal, patchy expression of CK20, CKAE1/3 and CK-HMW

Negative: NKX3.1, PSA, PSAP, P40, GATA3, synaptophysin and chromogranin

Retained: PTEN

Click on the below thumbnails to enlarge photos.

Quiz

1. What is the correct diagnosis?

a. Poorly differentiated prostatic adenocarcinoma (Gleason grade 5)

b. Adenoid cystic carcinoma

c. Prostatic basal cell carcinoma

d. Poorly differentiated urothelial carcinoma

This neoplasm is seen infiltrating the prostatic tissue in a solid/nested architectural pattern and the cells have a high nuclear to cytoplasmic ratio, with a distinctive basaloid appearance and areas of peripheral palisading. A prominent feature of this neoplasm is the presence of comedo-type necrosis in the central aspect of the nests, with discernible "ghost-cells". No cribriform growth pattern is identified. Based on these morphologic features, differential diagnostic considerations include a basal cell carcinoma of the prostate, poorly differentiated prostatic adenocarcinoma (Gleason pattern 5), poorly differentiated urothelial or squamous cell carcinoma as well as a high-grade neuroendocrine carcinoma. The morphology and CK7+/CK20- immunophenotype is compatible with a basal cell carcinoma and these tumors have been described to lack prostatic markers such as PSA/PSAP.
Loss of PTEN has been reported in at least one series of such cases. In addition, recent studies of solid-type prostatic basal cell carcinomas have shown that these tumors lack MYB translocations that are seen in a subset of adenoid cystic carcinomas of the prostate.

McKenney JK, Amin MB, Srigley JR et al. Basal cell proliferations of the prostate other than usual basal cell hyperplasia: a clinicopathologic study of 23 cases, including four carcinomas, with a proposed classification.
Am J Surg Pathol. 2004 Oct;28(10):1289-98.

Simper NB, Jones CL, MacLennan GT et al. Basal cell carcinoma of the prostate is an aggressive tumor with frequent loss of PTEN expression and overexpression of EGFR.
Hum Pathol. 2015 Jun;46(6):805-12.

Bishop JA, Yonescu R, Epstein JI et al. A subset of prostatic basal cell carcinomas harbor the MYB rearrangement of adenoid cystic carcinoma.
Hum Pathol. 2015 Aug;46(8):1204-8. .

About GUPS

The Genitourinary Pathology Society (GUPS) was formed with the vision of advancing the care of patients with urologic diseases through enhancements of best practices, research, and education in the subspecialty of Urological Pathology.

GUPS is an official Companion Society of the United States and Canadian Academy of Pathology (USCAP).

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