Invasive breast carcinoma - IARC

Fig. 2.40 Endometrioid cyst with atypia. The cyst
wall is lined by markedly atypical cells surrounded
by endometrial stroma.
can have minimal periglandular endometrial
stroma, cases in which endometrial
stroma is present throughout the lesion
are classified as endometriosis. The latter
can have all forms of endometrial
hyperplasia including those with atypia.
Clear cell tumours
Definition
Ovarian tumours, benign, borderline or
malignant, with an epithelial component
consisting most commonly of clear and
hobnail cells, but often containing other
cell types, which rarely predominate.
Histopathology
Clear cell tumours may by predominantly
epithelial or may also contain a prominent
fibromatous component. The epithelium
may consist of one or more cell
types. The most common cells are clear
cells and hobnail cells. Other cells that
may be present include cuboidal, flat,
oxyphilic and rare l y, signet-ring cells.
Most clear cell tumours are carcinomas,
and many have an adenofibromatous
b a c k g round. Benign and bord e r l i n e
clear cell tumours are rare and almost
always adenofibromatous.
ICD-O codes
Clear cell adenocarcinoma 8310/3
Clear cell adenocarcinofibroma 8313/3
Clear cell tumour of
borderline malignancy 8310/1
Clear cell adenofibroma
of borderline malignancy 8313/1
Clear cell cystadenoma 8310/0
Clear cell cystadenofibroma 8313/0
Clear cell adenocarcinoma
Definition
A malignant ovarian tumour composed of
glycogen-containing clear cells and hobnail
cells and occasionally other cell
types.
Epidemiology
The mean age of patients is 57 years.
Aetiology
Tumours may arise directly from the ovarian
surface epithelium, from inclusion
cysts or from an endometriotic cyst.
Clinical features
Clear cell tumours among all surface epithelial
cancers have the highest association
of ovarian and pelvic endometriosis
and paraendocrine hyperc a l c a e m i a
{3204}.
Macroscopy
The mean diameter of clear cell adenocarcinomas
is 15 cm. The tumours may
be solid, but more commonly the sectioned
surface reveals a thick-walled
unilocular cyst with multiple yellow fleshy
nodules protruding into the lumen or
multiloculated cysts containing watery or
mucinous fluid. Tumours associated with
endometriosis typically contain chocolate-brown
fluid.
Tumour spread and staging
Patients with clear cell adenocarcinomas
present as stage I disease in 33% of
cases, as stage II in 19%, as stage III in
29% and as stage IV in 9% {2233}.
Histopathology
Clear cell adenocarcinomas display
tubulocystic, papillary and solid patterns
that may be pure or mixed. The most
common patterns are papillary and tubulocystic.
Rarely, the tumour has a reticular
pattern similar to that of a yolk sac
tumour. Sheets of polyhedral cells with
abundant clear cytoplasm separated by
a delicate fibrovascular or hyalinized
stroma are characteristic of the solid pattern.
The tubulocystic pattern is characterized
by varying-sized tubules and
cysts lined by cuboidal to flattened
epithelium and occasionally hobnail
cells. The papillary pattern is characterized
by thick or thin papillae containing
Fig. 2.41 Clear cell adenocarcinoma arising within
an endometriotic cyst. The sectioned surface
shows a solid tumour within a chocolate cyst.
Fig. 2.42 Clear cell adenocarcinoma. The neoplasm has a solid and tubular pattern and is composed of
polygonal cells with abundant cytoplasm. Most cells have clear cytoplasm, but some are eosinophilic. Nuclei
are round but exhibit irregular nuclear membranes, nucleoli and abnormal chromatin patterns.
Surface epithelial-stromal tumours 137