[985] Progressive Loss of Basal Cells: A Possible Precursor of Limited Adenocarcinoma of Prostate

Mehrdad Nadji. University of Miami/Jackson Memorial Hospital, Miami, FL

Background: High grade prostatic intraepithelial neoplasia (HGPIN) has been established as both a precursor and predictor of prostatic adenocarcinomas. Because of their reported genetic similarities, a possible link has also been suggested between some cases of atypical adenomatous hyperplasia (AAH) and cancer. Fragmentation or focal loss of basal cells has been observed in both HGPIN and AAH of the prostate gland. This report describes the progressive loss in basal cells of normal appearing acini in the immediate vicinity of limited prostatic adenocarcinomas as a possible third precursor lesion.
Design: Radical prostatectomy specimens from 56 patients with biopsy proven prostatic carcinoma were selected for this study. These cases had limited cancer volumes (less than 1%). The Gleason grade and zonal distribution of tumors were recorded. Immunohistochemistry for basal cytokeratin 34βE12 was performed on all samples.
Results: The Gleason score of the tumors were 6 and 7, and except for two cases, all occurred in the peripheral zone of the prostate gland. Of the 56 carcinomas, 16 (28.5%) showed fragmentation or focal loss of basal cells in non-neoplastic acini immediately adjacent to tumors (within 2-3 low power fields). Epithelial-stromal separation was present and corresponded to the areas with absent basal cells. The partial absence of basal cells was more pronounced closer to cancer and in some cases, small acini with complete loss of basal cells appeared to be “budding off” from the “mother glands”. These newly separated small acini were cytologically similar to the adjacent non-neoplastic glands. None of these foci showed features of AAH or HGPIN.
Conclusions: A constellation of morphologic observations suggests that the progressive loss of basal cells in non-neoplastic acini immediately adjacent to small prostatic carcinomas may be the earliest event in the development of cancer. The cytology, histology and topography of these lesions are different from AAH and HGPIN. Larger volume tumors in all likelihood obscure these areas by expansion. Identification of these changes in prostate biopsies may potentially be useful in predicting the presence of nearby cancer.
Category: Genitourinary (including renal tumors)

Wednesday, March 6, 2013 1:00 PM

Poster Session VI # 144, Wednesday Afternoon


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