Invasive breast carcinoma - IARC

tumour size less than 5 x 5 mm {2575}.
Histogenesis
PPC is believed to develop de novo fro m
the peritoneal lining of the pelvis and
abdomen {2575}. It may develop in a
woman years after having bilateral
o o p h o rectomy {2262}. Some cases have
been shown to originate from multiple peritoneal
sites, supporting the hypothesis that
cells derived from the coelomic epithelium
may independently undergo malignant
t r a n s f o rmation {1954,2575,2576}.
Somatic genetics
PPC exhibits a distinct pattern of chromosomal
allelic loss compared to epithelial
ovarian cancer {176,421,1259}.
O v e re x p ression of the T P 5 3, E G F R,
ERBB2, ERBB3, and ERBB4 genes has
been reported, in addition to loss of normal
WT1 expression {2574,2575}. TP53
gene mutations commonly occur in PPC,
but KRAS mutations are very infrequent
{965,2575}. PPC BRCA1 mutation carriers
have a higher incidence of TP53
mutations, are less likely to exhibit
ERBB2 overexpression, and are more
likely to have a multifocal disease origin
{2575}. This unique molecular pathogenesis
of BRCA-related PPC is believed to
affect the ability of current methods to
reliably prevent or detect this disease
prior to metastasis {1402}.
Genetic susceptibility
G e rmline B R C A 1 mutations occur in PPC
with a frequency comparable to the
B R C A 1 mutation rate in ovarian cancer.
Although the penetrance is unknown,
PPC should be considered a possible
phenotype of the familial breast and ovarian
cancer syndrome {175}. The multifocal
disease origin is thought to explain
why PPC has been a common cause of
detection failures in familial ovarian cancer
screening programs. Scre e n i n g
strategies for these women cannot re l y
on ultrasonography and CA125 testing to
detect early disease {1402}.
Prognosis and predictive factors
The staging, treatment and prognosis of
PPC are similar to those of epithelial
ovarian cancer. Optimal surgical cytoreduction
for histological grade 1 and 2
Fig. 2.145 Low grade serous carcinoma, invasive growth pattern. Papillary aggregates of tumour without
connective tissue cores are present within retraction spaces surrounded by myxoid fibrous tissue. Note
several calcified psammoma bodies on the left.
lesions are associated with longer median
survival {2575}. Carboplatin or cisplatin
in conjunction with paclitaxel is the
c u r rent first-line re c o m m e n d e d
chemotherapy {1436}. The clinical
behaviour of psammocarcinoma more
closely resembles that of serous borderline
tumours than that of serous carcinomas
of the usual type. Patients with
psammocarcinoma follow a protracted
course and have a relatively favourable
prognosis {1001}.
Primary peritoneal borderline
tumours
Definition
A variety of extraovarian neoplasms that
histologically resemble borderline surface
epithelial-stromal tumours of ovarian
origin. By definition minimal or no ovarian
surface involvement is present.
Epidemiology
The age in the two largest series has
ranged from 16-67 years with a mean of
32 years.
Clinical features
Infertility and abdominal pain are the
most common presenting complaints
{204}. Occasional patients present with
an abdominal mass. At operation the
peritoneal lesions may be focal or diffuse.
They commonly appear as miliary
granules and may be mistaken for peritoneal
carcinomatosis.
Histopathology
The vast majority of cases are serous in
type. The histological appearance is similar
to that of non-invasive peritoneal
implants of epithelial or desmoplastic
type {278}. Psammoma bodies are a
prominent feature.
Prognosis and predictive factors
The usual treatment is hystere c t o m y,
bilateral salpingo-oophorectomy and
o m e n t e c t o m y. Younger patients who
desire to maintain fertility may be treated
conservatively {278}. The prognosis is
excellent. Occasional tumour re c u r-
rences with bowel obstruction have been
described. Rarely, the patient may develop
an invasive low grade serous carcinoma
of the peritoneum. Rare deaths due
to tumour have been reported.
202 Tumours of the ovary and peritoneum