Microcystic adenocarcinoma of the prostate-pseudobenign carcinoma

Reference :

Microcystic Adenocarcinoma of the Prostate: A Variant of Pseudohyperplastic and Atrophic Patterns : Yaskiv, Oksana et al.
The American Journal of Surgical Pathology: April 2010 - Volume 34 - Issue 4 - pp 556-561

Do you see anything in this prostate that's worrisome for malignancy?
dilated glands admixed with small acini in a nodule
I don't, at least not at this power, and yet this is an example of "microcystic" adenocarcinoma of the prostate. Higher power will show clear-cut cytologic features of malignancy.
If this doesn't concern you about the risk of scanning prostate slides at 4x, it should!

Microcystic adenocarcinoma with dilated and crowded glands displaying a predominantly flat lining layer

Microcystic adenocarcinoma with jumbled arrangement of dilated malignant glands.

Microcystic adenocarcinoma with atrophic features.

Dilated malignant glands with adjacent usual small acinar adenocarcinoma glands for size reference

Numerous crystalloids in dilated glands of microcystic adenocarcinoma.

Nuclear atypia with prominent nucleoli in the lining layer of 2 microcystic adenocarcinoma glands.

Microcystic adenocarcinoma extending into periprostatic adipose tissue, along with several small acinar adenocarcinoma glands.

Overerexpression of α-methylacyl CoA racemase in microcystic adenocarcinoma, with luminal accentuation. No basal cells are detected with this p63/AMACR cocktail immunohistochemical stain.

Overexpression of AMACR with granular cytoplasmic signal in microcystic adenocarcinoma gland with basal cell absence (right). Internal control benign atrophic glands on left show basal cell presence, with p63 marker, and lack of AMACR staining.

Basal cell absence in microcystic adenocarcinoma (left) compared with benign atrophic glands with basal cells (right), as assessed with 34βE12 immunostain.

Microcystic adenocarcinoma in needle biopsy tissue
Reference :
Microcystic Adenocarcinoma of the Prostate: A Variant of Pseudohyperplastic and Atrophic Patterns : Yaskiv, Oksana et al.The American Journal of Surgical Pathology: April 2010 - Volume 34 - Issue 4 - pp 556-561

Cystic glandular dilatation is a common finding in benign prostatic tissues, being identified in benign prostatic hyperplasia (BPH) in the transition zone and as cystic atrophy in the peripheral zone. Diagnostic awareness that acinar prostatic adenocarcinoma may exhibit cystic dilatation is important to avoid underdiagnosis of prostatic adenocarcinoma.

Cystic change in adenocarcinoma of the prostate is unusual and may be confused with benign cystic atrophy.Microcystic adenocarcinoma of the prostate is a distinctive histomorphologic presentation of prostatic adenocarcinoma that is deceptively benign-looking at low magnifications.

Detection of intraluminal crystalloids or wispy blue mucin at low magnification, immunostains for α-methylacyl CoA racemase, and basal cells, and a search for adjacent usual small acinar adenocarcinoma are helpful diagnostic aids. Diagnostic awareness of this growth pattern of prostatic carcinoma is important to avoid underdiagnosis of adenocarcinoma of the prostate.


Manny said...

I (and Gleason) did not know the existence of this form of prostate cancer until we started using the "prostate coktail".

Question: how should microcystic carcinoma be graded?

Penegra said...

More than 2 million men in the US count themselves as prostate cancer survivors. Whether you’re worried about developing prostate cancer, making decisions about your treatment, or trying to stay well after treatment…

calif-ua said...

This is very interesting case.
And good question about grading rules for this type of growth.

List of all the posts

Interesting Case

Clinical History:

53 years male,History of hypertension and tachycardia,MRI abdomen:-Left adrenal mass:- size 5.8 cm Right renal mass:- size-3.0cm Microscopic examination of the renal mass showed vascular tumor with diffuse sheets of clear cells having Fuhrman grade III nuclei. There was no evidence of necrosis within the tumor. There was no evidence of extraparenchymal invasion.
Gross examination of the left adrenal gland revealed cortically centered, solid and multinodular mass measuring 6.5 x 6.0 x 5.0 cm and weighing 122 grams. The tumor was encapsulated but showed evidence of extraparenchymal penetration. The tumor had golden brown cut surface with areas of hemorrhage and necrosis. The partial nephrectomy showed 3.0cm x 3.0cm x 3.0 cm yellow solid mass which did not invade into the perinephric adipose tissue.
Microscopically, the adrenal mass had predominant diffuse sheets and focal trabecular arrangements. The former pattern was present in about third of tumor. The cells had clear cytoplasm and round to ovoid nuclei with conspicuous nucleoli. Mitotic rate was 9/50 HPF and included atypical forms. Gross necrosis and capsular invasion were documented microscopically. There was no evidence of lymphovascular invasion. Considering the above mentioned features, a Weiss histopathologic score2 of 7/9 was applied.


The differential diagnosis included Renal Cell Carcinoma (RCC) with contralateral adrenal metastasis, Adrenocortical carcinoma (ACC) with contralateral renal metastasis, synchronous RCC and ACC or synchronous RCC and adrenocortical adenoma. A panel of immunohistochemical stains was performed to sort out the diagnosis. Adrenal tumor demonstrated strong Vimentin positivity and is negative for CK7, CK20, E1/AE3, EMA, Synaptophysin and S100.Renal cell carcinoma was positive for CK7, AE1/AE3, EMA (weak) and Vimentin. It was negative for CK20, Synaptophysin and S100. The difference of immunoprofile between the two tumors documented that they originated from two different primaries.

Final Diagnosis:

The diagnosis of synchronous RCC and ACC rather than metastasis influences the prognosis.


The longest disease free interval after removal of contralateral adrenal metastasis was 12.1 years8 and the longest crude survival was 14.3 years. In contrast non metastazing RCC has an excellent prognosis if no metastasis developed.