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

Urothelial carcinoma
D.J. Grignon
Definition
Urothelial carcinoma involving the
prostate.
ICD-O code 8120/3
Epidemiology
The frequency of primary urothelial carcinoma
ranges from 0.7-2.8% of prostatic
tumours in adults {942,943}. Most
patients are older with a similar age distribution
to urothelial carcinoma of the
bladder (range 45-90 years) {942,1231}.
In patients with invasive bladder carcinoma,
there is involvement of the prostate
gland in up to 45% of cases {1596,
1907,2837}. This is highest when there is
multifocality or carcinoma in situ associated
with the invasive carcinoma {1907}.
Etiology
Primary urothelial carcinomas presumably
arise from the urothelial lining of the prostatic
urethra and the proximal portions of
prostatic ducts. It has been postulated
that this may arise through a hyperplasia
to dysplasia sequence, possibly from
reserve cells within the urothelium
{696,1278,2673}. Secondary urothelial
carcinoma of the prostate is usually
accompanied by CIS of the prostatic urethra
{2673}. Involvement of the prostate
appears to be by direct extension from the
overlying urethra, since in the majority of
cases the more centrally located prostatic
ducts are involved by urothelial neoplasia
to a greater extent than the peripheral
ducts and acini. Less commonly, deeply
invasive urothelial carcinoma from the
bladder directly invades the prostate.
Localization
Primary urothelial carcinoma is usually
located within the proximal prostatic
ducts. Many cases are locally advanced
at diagnosis and extensively replace the
prostate gland.
Clinical features
Signs and symptoms
Primary urothelial carcinoma presents in
a similar fashion to other prostatic masses
including urinary obstruction and
haematuria {943,2159}. Digital rectal
examination is abnormal in the majority
but is infrequently the presenting sign
{1951}. There is limited data on PSA levels
in patients with urothelial carcinoma
of the prostate. In one series 4 of 6
patients had elevated serum PSA (>4
ng/ml) in the absence of prostatic adenocarcinoma
{1951}. In some cases
patients present with signs and symptoms
related to metastases {2159}.
Methods of diagnosis
Most cases are diagnosed by
transurethral resection or less often needle
biopsy {1951}. In all suspected cases
the possibility of secondary involvement
from a bladder primary must be excluded;
the bladder tumour can be occult
and random biopsies may be necessary
to exclude this possibility {2313,2905}.
Biopsies of the prostatic urethra and suburethral
prostate tissue are often recommended
as a staging procedure to
detect secondary urothelial cancer
involving the prostate of patients undergoing
conservative treatment for superficial
bladder tumours.
Tumour spread and staging
In situ carcinoma can spread along
ducts and involve acini, or the tumour
can spread along ejaculatory ducts and
into seminal vesicles. Subsequent
spread is by invasion of prostatic stroma.
Local spread beyond the confines of the
prostate may occur. Metastases are to
regional lymph nodes and bone {2556}.
Bone metastases are osteolytic. These
tumours are staged as urethral tumours
{944}. For tumours involving the prostatic
ducts, there is a T1 category for invasion
of subepithelial connective tissue distinct
from invasion of prostatic stroma (T2).
The prognostic importance of these categories
has been confirmed in clinical
studies {442}.
Histopathology
The full range of histologic types and
grades of urothelial neoplasia can be
Fig. 3.73 Urothelial carcinoma invading prostate.
seen in primary and secondary urothelial
neoplasms of the prostate {442}. A few
examples of papillary urothelial neoplasms
arising within prostatic ducts are
described {1278}. The vast majority, however,
are high-grade and are associated
with an in situ component {442,
899,1893,1951,2445,2580}. The in situ
component has the characteristic histologic
features of urothelial carcinoma in
situ elsewhere with marked nuclear pleomorphism,
frequent mitoses and apoptotic
bodies. A single cell pattern of
pagetoid spread or burrowing of tumour
cells between the basal cell and secretory
cell layers of the prostate is characteristic.
With extensive tumour involvement,
urothelial carcinoma fills and expands
ducts and often develops central comedonecrosis.
Stromal invasion is associated
with a prominent desmoplastic stromal
response with tumour cells arranged
in small irregular nests, cords and single
cells. Inflammation in the adjacent stroma
frequently accompanies in situ disease
but without desmoplasia. With stromal
invasive tumours, squamous or glandular
differentiation can be seen.
Angiolymphatic invasion is often identified.
Incidental adenocarcinoma of the
prostate is found in up to 40% of cystoprostatectomy
specimens removed for
urothelial carcinoma of the bladder and
can accompany primary urothelial carcinoma
{1772}.
In cases of direct invasion of the prostate
from a poorly differentiated urothelial carcinoma
of the bladder, a common prob-
202 Tumours of the prostate