Invasive breast carcinoma - IARC

A
Fig. 2.29 Ovarian endometrioid adenocarcinoma arising from an endometriotic cyst. A This solid and cystic tumour forms polypoid structures. The patient had a synchronous
endometrioid adenocarcinoma of the uterine corpus. B Well differentiated endometrioid adenocarcinoma is seen to the right and an endometriotic cyst on the left.
B
Endometrioid tumours
Definition
Tumours of the ovary, benign, low malignant
potential or malignant, that closely
resemble the various types of endometrioid
tumours (epithelial and/or stromal) of
the uterine corpus. Although an origin
from endometriosis can be demonstrated
in some cases, it is not required for the
diagnosis.
ICD-O codes
Endometrioid adenocarcinoma,
not otherwise specified 8380/3
Variant with squamous
differentiation 8570/3
Ciliated variant 8383/3
Oxyphilic variant 8290/3
Secretory variant 8382/3
Adenocarcinofibroma 8381/3
Malignant müllerian
mixed tumour 8950 / 3
Adenosarcoma 8933/3
Endometrioid stromal sarcoma 8930/3
Endometrioid borderline tumour 8380/1
Cystadenoma 8380/0
Adenofibroma;
cystadenofibroma 8381/0
Endometrioid adenocarcinoma
Definition
A malignant epithelial tumour of the ovary
that closely resembles the common variant
of endometrioid carcinoma of the uterine
corpus. Although an origin from endometriosis
can be demonstrated in some
cases, it is not re q u i red for the diagnosis.
Epidemiology
Endometrioid carcinomas account for
10-20% of ovarian carcinomas {1409,
2489} and occur most commonly in
women in the fifth and sixth decades of
life {2773}.
Aetiology
Up to 42% of the tumours are associated
with endometriosis in the same ovary or
elsewhere in the pelvis {676,932,1927,
2489,2287a} and 15-20% are associated
with endometrial carcinoma {1477,1479,
1683,3239}. These associations suggest
that some endometrioid ovarian carcinomas
may have the same risk factors for
their development as endometrial carcinomas
{613}. Patients whose tumours
occur in association with endometriosis
are 5-10 years younger on average than
patients without associated ovarian
endometriosis {2600}.
Clinical features
Like most ovarian carcinomas, many endometrioid
carcinomas are asymptomatic.
Some present as a pelvic mass, with or
without pain and may be associated with
endocrine symptoms secondary to stero i d
h o rmone secretion by the specialized ovarian
stroma {1790}. Serum CA125 is elevated
in over 80% of the cases {946,1603}.
Macroscopy
The tumours, typically measuring 10-20
cm in diameter, are solid, soft, friable or
cystic with a fungating mass protruding
into the lumen. They are bilateral in 28%
of the cases.
Tumour spread and staging
Stage I carcinomas are bilateral in 17% of
the cases {2233}. The stage distribution of
endometrioid carcinomas differs from that
of serous carcinomas. According to the
FIGO annual re p o rt, 31% of the tumours
a re stage I; 20%, stage II; 38%, stage III;
and 11%, stage IV {2233}.
Histopathology
Ovarian endometrioid carcinomas closely
resemble endometrioid carcinomas of
the uterine corpus. The well differentiated
form shows round, oval or tubular glands
lined by stratified nonmucin-containing
epithelium. Cribriform or villoglandular
patterns may be present. Squamous diff
e rentiation occurs in 30-50% of the
cases, often in the form of morules (cytologically
benign-appearing squamous
cells) {341,2605}. The designation
"endometrioid carcinoma with squamous
differentiation" (rather than adenoacanthoma
and adenosquamous carcinoma)
is favoured {2604,2605}. Aggregates of
spindle-shaped epithelial cells are an
occasional finding in endometrioid carcinoma
{2942}. Occasionally, the spindle
cell nests undergo a transition to clearly
recognizable squamous cells suggesting
that the former may represent abortive
squamous differentiation {2605}.
Rare examples of mucin-rich, secretory,
ciliated cell and oxyphilic types have
been described {759,1187,2258}. In the
mucin-rich variant glandular lumens and
the apex of cells are occupied by mucin
{2605}. The secretory type contains vacuolated
cells resembling those of an
130 Tumours of the ovary and peritoneum