prostatic atypical adenomatous hyperplasia

PO

Definition: A microscopic proliferation of small glands with minimal atypia; may be mistaken for low grade adenocarcinoma. It is sound almost exclusively in transition zone (2% of TURPs, @<@ 1% of core biopsies).

Microscopy

The glands are variable in size and show round, oval, or irregular lumina. The cytoplasm is pale in contrast to the amphophilic cytoplasm usually seen in cancer.

The nuclei are not enlarged appreciably and prominent nucleoli are not present.

However, approximately 30% of cases of adenosis may show prominent nucleoli.

Higher magnification shows pale glands lacking cytologic atypia in a focus of atypical adenomatous hyperplasia in a prostate needle biopsy.

Images

 http://webpathology.com/image.asp?n=4&Case=18
 http://webpathology.com/image.asp?case=18&n=8

IHC

Immunohistochemical markers for basal cells are useful in confirming the diagnosis of atypical adenomatous hyperplasia (adenosis) in prostate needle biopsies.

The basal cell layer is fragmented but present in at least some of the acini within the focus.

Since the glands lacking basal cells are morphologically similar to those with patchy staining, the entire focus is considered benign.

The immunostain for high molecular weight cytokeratin 34bE12 demonstrates fragmented basal cell layer in the previous focus of atypical adenomatous hyperplasia. Some glands are completely negative, where as others show only one or two basal cells.

See also

 adenosis
 atypical adenomatous hyperplasia