1), while the remaining 33% (6/18) showed acinar adenocarcinoma. Only 2 of the original pathology reports described the presence of ductal cancer (sensitivity 17%).
Ductal adenocarcinoma is relatively rare, is frequently associated and inter-mixed with acinar adenocarcinoma, and can be confused with microscopic mimickers.
Based on morphological features, 10 out of 150 cases (7%) were characterized as ductal adenocarcinoma and 140 cases (93%) exhibited the morphological features of acinar adenocarcinoma
. Ductal carcinoma cases were characterized by distinctive pseudostratified columnar epithelial cells in papillary or cribriform architectures, whereas acinar tumors exhibited glands and acini lined by a single layer of cuboidal cells [Figure 1].
It is important to stress that PDCa is an aggressive form of invasive adenocarcinoma (analogous to GS 8 or above acinar adenocarcinoma
), often seen in association with conventional acinar adenocarcinoma
and rarely (<1%) in its pure form.
Immunohistochemical antibody cocktail staining (p63/HMWCK/AMACR) of ductal adenocarcinoma and Gleason pattern 4 cribriform and noncribriform acinar adenocarcinomas
of the prostate.
Invasive acinar adenocarcinoma
may closely mimic IDC-P when it has cribriform or solid architecture (Gleason pattern 4 or 5).
Microscopic examination of the resection specimen revealed prostatic acinar adenocarcinoma
, which was unilateral, multifocal, and predominantly peripheral.
Features seen within PTAT that create difficulty in distinguishing it from prostatic acinar adenocarcinoma
include the following: (1) crowded and sometimes disorganized patterns of growth, (2) relatively high nuclear to cytoplasmic ratio with slightly enlarged nuclei, (3) straight luminal borders in some glands, (4) the presence of visible but small nucleoli, (5) negative staining of some glands for basal cells markers, and (6) positive staining of some glands for racemase (Figures 1, A through F, and 2, A through F).
The presence of nuclear hyperchromasia, with smudged chromatin and scattered pleomorphic cells (sometimes striking) beyond what is seen in acinar adenocarcinoma
, as well as the presence of lipofuscin granules, occasional intranuclear inclusions, and in the case of the seminal vesicle, a muscular wall, are all helpful clues leading toward the correct diagnosis.
The single cytology pleural fluid specimen was an acinar adenocarcinoma
, and the 2 cases of metastasis to lymph nodes (patients 18 and 19) showed mixed subtype adenocarcinoma with papillary, and a small solid pattern in one of the nodes and an acinar pattern in the other.
Differentiation of adenoid cystic/basal cell carcinoma from basal cell hyperplasia and cribriform pattern of acinar adenocarcinoma
may be difficult.
Papillary ductal (endometrioid) adenocarcinoma of the prostate and acinar adenocarcinoma
may present as exophytic papillary proliferation into the prostatic urethra and, therefore, could potentially be seen in urine samples.