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

Basal cell carcinoma
P.H. Tan
A. Billis
Definition
This is a neoplasm composed of prostatic
basal cells. It is believed that a subset
of basal cells are prostatic epithelial stem
cells, which can give rise to a spectrum
of proliferative lesions ranging from basal
cell hyperplasia to basal cell carcinoma
{271,1139,2007,2410}.
ICD-O code 8147/3
Clinical features
Patients are generally elderly, presenting
with urinary obstruction with TURP being
the most common tissue source of diagnosis.
The youngest reported case was
28 years old {597}.
Histopathology
Some tumours resemble its namesake
in the skin, comprising large basaloid
nests with peripheral palisading and
necrosis. Other patterns have histologic
similarity to florid basal cell hyperplasia
or the adenoid basal cell pattern
of basal cell hyperplasia (the latter pattern
of cancer occasionally referred to
as adenoid cystic carcinoma).
Histologic criteria for malignancy that
distinguish it from basal cell hyperplasia
include an infiltrative pattern,
extraprostatic extension, perineural
invasion, necrosis and stromal desmoplasia.
Basal cell carcinoma shows immunoreactivity
for keratin 34βE12, confirming
its relationship with prostatic basal
cells. S-100 staining is described as
weak to intensely positive in about 50%
of tumour cells {954,2893}, raising the
possibility of myoepithelial differentiation;
but there is no corroborative antismooth
muscle actin (HHF35) reactivity
{954} nor ultrastructural evidence of
a myoepithelial nature {2893}.
Distinction from basal cell hyperplasia
with a pseudoinfiltrative pattern or
prominent nucleoli can be difficult;
basal cell carcinoma shows strong
BCL2 positivity and high Ki-67 indices
as compared to basal cell hyperplasia
{2868}.
Fig. 3.80 Basal cell carcinoma resembling basal cell hyperplasia.
A
B
Fig. 3.81 Basal cell carcinoma A Note central comedonecrosis. B Basal cell carcinoma resembling adenoid
cystic carcinoma. C Perineural invasion.
C
Prognosis
The biologic behaviour and treatment of
basal cell carcinoma is not well elucidated
in view of the few cases with mostly
short follow-up. Local extra-prostatic
extension may be seen, along with distant
metastases {597,1160}. A benign
morphologic counterpart to basal cell
carcinoma (basal cell adenoma) has
been proposed, although it should be
considered as florid nodular basal cell
hyperplasia.
206 Tumours of the prostate