Of these 93/120 cases (77.5%) were diagnosed as carcinoma which comprised 88/93 cases (94.62%) of acinar adenocarcinoma
, 3/93 cases (3.22%) of ductal adenocarcinoma and 2/93 cases of signet ring cell variant of adenocarcinoma; 1/120 diagnosed as a case of prostatitis, 5/120 cases as atypical glands suspicious for malignancy and 3/120 cases as high-grade PIN.
The grade as well as extent of the acinar adenocarcinoma
component in mixed small cell adenocarcinoma in the prostate is variable.
On histopathology, ductal cancer can resemble high-grade prostatic intraepithelial neoplasia (HGPIN), intraductal prostatic carcinoma, the hyperplastic variant of prostate cancer, cribriform Gleason Pattern 4 acinar adenocarcinoma
, and metastases (including from the colon and bladder).
The diagnosis of ductal and acinar adenocarcinoma
generally depends on histopathologic and immunohistochemical examination.
Hematoxylin-eosin images showing the morphologic spectrum of glandular tumors that may secondarily involve the urachus or urinary bladder, including (A) colorectal adenocarcinoma; (B) prostatic acinar adenocarcinoma
; (C) prostatic ductal adenocarcinoma; (D) metastatic lobular breast carcinoma; (E) metastatic diffuse- type gastric adenocarcinoma; and (F) metastatic endometrioid carcinoma.
Invasive Acinar Adenocarcinoma
(Cribriform Gleason Pattern 4)
The term Paneth cell-like change has been used to describe distinctive eosinophilic neuroendocrine cells that can be seen in benign prostate glands, high-grade prostatic intraepithelial neoplasia, intraductal carcinoma, and usual acinar adenocarcinoma
of the prostate (Figure 3, B).
Owing to the partial collapsed irregular alveolar walls, structures looking like irregular acini may mimic acinar adenocarcinoma
, also seen in an earlier reproducibility study among 28 pathologists (6) (Figure 2, A through F; images not published with previous study).
Intraductal carcinoma of the prostate (IDCP) was historically a term used variably to describe prostatic acinar adenocarcinoma
, prostatic ductal adenocarcinoma, and urothelial carcinoma extension into prostatic ducts and acini.
However, when the alveolar architecture is lost and/or myofibroblastic stroma is present, invasive acinar adenocarcinoma
is considered present.
(1,2) Among these variants are subtypes of prostatic acinar adenocarcinoma
such as vacuolar, foamy gland, atrophic, and pseudohyperplastic types.
PARTIAL ATROPHY VERSUS PROSTATIC ACINAR ADENOCARCINOMA
Infiltrating cribriform acinar adenocarcinoma
(Gleason patterns 4 or 5, depending on whether comedonecrosis is present) closely mimics cribriform IDC-P.
For example, a significant difference was found for a case for which the evaluation by microscopy and the subsequent staining with cytokeratin 34BE12 verified the presence of a small focus (<1 mm) of prostatic acinar adenocarcinoma
in a biopsy specimen, originally reported as a negative result (case 31).