Invasive breast carcinoma - IARC

A
Fig. 2.28 Mucinous cystic tumour of the appendix associated with synchronous mucinous ovarian tumours.
A The appendiceal lesion shows pseudostratified mucinous epithelium (colonic type) with mild nuclear
atypia. B The mucinous epithelium of the ovarian lesion shows strong immunoreactivity for cytokeratin 20
and was negative for cytokeratin 7, strongly supporting the appendiceal origin of the tumour.
the origin of the pseudomyxoma peritonei
has been disputed. A majority of
investigators believe that the ovarian
tumour(s) are secondary in almost all
such cases {2294,2407,3199}. However,
a synchronous origin in both organs has
also been proposed {2623}.
Clonality studies have demonstrated
identical KRAS mutations or the lack of
them in both the appendiceal and the
simultaneous ovarian tumours {590,
2830}. LOH analysis has shown similar
findings in three cases and divergent
findings in three; this latter observation
appears to indicate that some simultaneous
tumours are independent primaries
B
{590}, though genetic progression of the
metastatic tumours could also account
for the disparity of these results.
The ovarian tumours are usually classified
as either mucinous cystadenomas
or intestinal-type borderline tumours.
The epithelial cells within them are often
found floating in mucin that dissects into
the ovarian stroma (pseudomyxoma
ovarii). They are well diff e rentiated and
often have a tall columnar appearance
with abundant mucinous cytoplasm that
is positive for cytokeratin 7 in approximately
one-half of the cases {1075,
2408}. The latter finding differs from that
of primary ovarian mucinous cystadenoma
or intestinal-type borderline tumours
most of which are cytokeratin 7-positive.
The appendiceal tumour may be quite
small relative to the ovarian tumour(s)
and may not be appreciated macros
c o p i c a l l y. Thus, removal and thoro u g h
histological examination of the appendix
is indicated in cases of pseudomyxoma
peritonei with a mucinous cystic ovarian
t u m o u r. In cases where an appendiceal
mucinous neoplasm is found, it should
be considered as the primary site and
the ovaries as secondary. If the appendix
has not been examined histologically
and the ovarian tumours are bilateral,
or unilateral in the absence of an ipsilateral
dermoid cyst, the appendix should
also be considered primary. If an
appendiceal mucinous neoplasm is not
found after thorough histological examination,
if the appendix had been
removed previously in the absence of
pseudomyxoma peritonei or if the ovarian
tumour is accompanied by a dermoid
cyst in the absence of either a
m a c roscopic or histological appendiceal
lesion, the ovarian tumour may be
c o n s i d e red to be the source of the
pseudomyxoma peritonei {1613}. In
equivocal cases cytokeratin 7 negativity
in the ovarian tumour strongly suggests
that it is metastatic.
Table 2.04
Behaviour of problematic mucinous ovarian neoplasms with invasive implants or pseudomyxoma peritonei.
Tumour type Macroscopy Histopathology Appearance of Usual behaviour in cases
extraovarian disease with extraovarian disease
Intestinal type MBT Large, smooth surfaced Cysts are lined with slightly Invasive peritoneal implants Prognosis is poor.
multilocular cyst, stratified intestinal type cells without PP Cases with invasive implants
bilateral in 5% with mild nuclear atypia and This is a rare finding are likely due to unsampled
no detached cell clusters
invasive areas in the
Usually CK7 positive
ovarian tumour.
Intestinal type MBT Same Same, with foci of malignant- Invasive peritoneal Same as above
with intraepithelial appearing nuclei and often highly implants without PP
carcinoma
stratified, solid or cribriform areas
Endocervical-like Smaller with fewer cysts and Cysts composed of complex, Invasive or noninvasive Benign
MBT may be associated with endo- bulbous papillae with highly peritoneal implants
metriosis, bilateral in 40%
stratified, benign-appearing
mucinous and eosinophilic cells,
detached cell clusters and
numerous neutrophils
Mucinous ovarian Bilateral in a high percentage Usually resembles intestinal type PP Variable, depending on the
tumours associated of cases of MBT often with pseudomyxoma Often primary appendiceal degree of atypia of the tumour
with PP o v a r i i tumour cells in PP
PP = Pseudomyxoma peritonei; MBT = mucinous borderline tumour
Surface epithelial-stromal tumours 129