Clinical history: 67 year old male with elevated PSA.
What is the diagnosis?
Basal cell hyperplasia in a background of chronic inflammation
Basal cell hyperplasia (BCH) consists of a proliferation of basal cells two or more cells thick at the periphery of prostatic acini. It sometimes appears as small nests of cells surrounded by compressed stroma, often associated with chronic inflammation. The nests may be solid or cystically dilated, and occasionally are punctuated by irregular round luminal spaces, creating a cribriform pattern. BCH frequently involves only part of an acinus, and sometimes protrudes into the lumen, retaining the overlying secretory cell layer; less commonly, there is symmetric duplication of the basal cell layer at the periphery of the acinus. The proliferation may protrude into the acinar lumen, retaining the overlying secretory luminal epithelium. Symmetric circumferential thickening of the basal cell layer is less frequent than eccentric thickening, and these changes do not result from tangential sectioning.
The basal cells in BCH are enlarged, ovoid or round, and plump, with large pale ovoid nuclei, finely reticular chromatin, and a moderate amount of cytoplasm. Nucleoli are usually inconspicuous.
Clear cell change is common in BCH, often with a cribriform pattern; cribriform pattern without clear cell change is rare. Squamous metaplasia is infrequent, usually associated with infarction. Ch4ronic inflammation is a common association, but is non-specific.
Florid BCH consists of compact glandular proliferation with solid nests. The cytology in some areas looks disturbing because the basaloid cells have moderately enlarged nuclei, often with prominent nucleoli; a few mitotic figures are present; the intervening stroma is scant and cellular; the lesion is not well circumscribed; and basaloid structures are intermingled with the surrounding glands, giving the pimpression of “infiltration.”