Eble JN, Sauter G., Epstein JI, Sesterhenn IA - iarc

A
B
Fig. 3.25 A Pseudohyperplastic adenocarcinoma. Branding and pepillary type of and growth is typical.
B Perineural invasion. C Higher magnification, showing prominent nucleoli.
adenocarcinoma of the prostate. In
almost all such cases, despite foamy
glands cancer’s benign cytology, the
ordinary adenocarcinoma component is
not low grade. Consequently, foamy
gland carcinoma appears best classified
as intermediate grade carcinoma.
C
Colloid & signet ring variant
Using criteria developed for mucinous
carcinomas of other organs, the diagnosis
of mucinous adenocarcinoma of the
prostate gland should be made when at
least 25% of the tumour resected contains
lakes of extracellular mucin. On
biopsy material, cancers with abundant
extracellular mucin should be diagnosed
as carcinomas with mucinous features,
rather than colloid carcinoma, as the
biopsy material may not be reflective of
the entire tumour. Mucinous (colloid)
adenocarcinoma of the prostate gland is
one of the least common morphologic
variants of prostatic carcinoma
{710,2207,2274}. A cribriform pattern
tends to predominate in the mucinous
areas. In contrast to bladder adenocarcinomas,
mucinous adenocarcinoma of
the prostate rarely contain mucin positive
signet cells. Some carcinomas of the
prostate will have a signet-ring-cell
appearance, yet the vacuoles do not
contain intracytoplasmic mucin {2206}.
These vacuolated cells may be present as
singly invasive cells, in single glands, and
in sheets of cells. Only a few cases of
prostate cancer have been reported with
mucin positive signet cells {1057,2660}.
One should exclude other mucinous
tumours of non-prostatic origin based on
morphology and immunohistochemistry
and if necessary using clinical information.
Even more rare are cases of in-situ and
infiltrating mucinous adenocarcinoma
arising from glandular metaplasia of the
prostatic urethra with invasion into the
prostate {2636}. The histologic growth
pattern found in these tumours were
identical to mucinous adenocarcinoma of
the bladder consisting lakes of mucin
lined by tall columnar epithelium with
goblet cells showing varying degrees of
nuclear atypia and in some of these
cases, mucin-containing signet cells.
These tumours have been negative
immunohistochemically for PSA and PAP.
A
B
Fig. 3.26 A Cancer of pseudohyperplastic type. Crowded glands with too little stroma to be a BPH. B Pseudohyperplastic adenocarcinoma with prominent nucleoli (arrow).
176 Tumours of the prostate