ACase of Intratesticular Endometrioid Papillary Cystadenocarcinoma
Kazuyuki Numakura, Norihiko Tsuchiya, Hiroshi Tsuruta, Takashi Obara, Mitsuru Saito, Takamitsu Inoue,
Shintaro Narita, Yohei Horikawa, Shigeru Satoh, Hiroshi Nanjyo and Tomonori Habuchi*
Department of Urology, Akita University Graduate School of Medicine, Akita, Japan
*For reprints and all correspondence: Tomonori Habuchi, Department of Urology, Akita University Graduate School
of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan. E-mail: email@example.com
Received November 20, 2010; accepted February 11, 2011
We report a case of intratesticular endometrioid papillary cystadenocarcinoma. A 73-year-
old man was admitted for a painless right scrotal swelling. Ultrasonography and com-
puted tomography revealed a large cystic mass in the right testis. Right scrotum puncture
revealed xanthochromic fluid with negative cytology. Three months later, follow-up com-
puted tomography showed enlargement of the cystic mass. Right high orchiectomy was
performed because a testicular malignancy was suspected. The pathological diagnosis
was endometrioid papillary cystadenocarcinoma, and the cells were strongly positive for
the estrogen and progesterone receptors. Testicular neoplasms resembling common
ovarian-type epithelial tumors are very rare. This is the first report of endometrioid papil-
lary cystadenocarcinoma of the testis.
Key words: testicular tumor – endometrioid carcinoma – estrogen receptor – progesterone receptor
Endometrioid papillary cystadenocarcinoma of the testis
is a rare neoplasm that is practically indistinguishable
from that found in the ovary (1). The histology of
ovarian-type epithelial tumors of the testis has been
classified into the following types: borderline microinva-
sive serous tumor and serous carcinoma, intra- and para-
testicular mucinous tumor (with different grades of
malignancy), and endometrioid adenocarcinoma and
Brenner (transitional cell) tumor (2). The histopathogen-
esis of ovarian-type epithelial tumors may be associated
with remnants of mu ¨llerian tissue or mu ¨llerian metaplasia
of the tunica vaginalis in a testis or paratestis (3). Here
we present a case of endometrioid papillary cystadeno-
carcinoma of the testis.
A 73-year-old man was admitted for a painless right scrotal
swelling that persisted for a year and rapidly increased in
size over the past month, causing discomfort in the right
groin. Physical examination revealed swelling of the
right hemiscrotum and a normal testis on the left.
Ultrasonography showed a heterogeneous cystic lesion with
a maximum diameter of 5 cm in the right testis. Serum
human chorionic gonadotropin (hCG) and alpha-fetoprotein
(AFP) levels were within normal limits. Computed tomogra-
phy (CT) demonstrated a cystic mass in the right testis
without invasion to adjacent structures or distant metastasis
(Fig. 1). Right scrotum puncture revealed xanthochromic
fluid with negative cytology. These clinical findings enabled
careful monitoring of the patient without treatments.
However, a follow-up CT carried out 3 months later demon-
strated enlargement of the right cystic mass. Right high orch-
iectomy was performed because a malignant testicular tumor
Pathological examination of the surgical specimen
revealed a 9 cm multilocular cystic lesion in the testis
containing viscous fluid. The lining surface showed
several grayish-white papillary excrescences (Fig. 2). The
Microscopically, the cyst wall was composed of dense
fibrous tissue lined by a partially ciliated cuboidal and
columnar epithelium, and intracystic excrescences com-
posed of fibrovascular villous structures lined by stratified
columnar epithelium with formation of micropapillary
tufts (Fig. 3). The cells showed mild nuclear pleomorph-
ism but no increased mitotic activity. Detached clusters of
epithelial cells were present in the cyst space. The lining
# The Author (2011). Published by Oxford University Press. All rights reserved.
Jpn J Clin Oncol 2011;41(5)674–676
Advance Access Publication 7 April 2011
by guest on July 30, 2015
tumor cells were strongly positive for estrogen receptor
(ER), progesterone receptor (PgR) and placental alkaline
phosphatase (Fig. 4A and B). Immunohistochemical stain-
ing of other testicular tumor markers such as carcinoem-
bryonic antigen (CEA), AFP and hCG were negative. The
surrounding compressed testicular tissue as well as the
epididymis and spermatic cord were unremarkable.
Consequently, this case was diagnosed as endometrioid
The postoperative period was uneventful, and no recur-
rence has been observed after 3 years of follow-up.
Testicular and paratesticular tumors resembling ovarian neo-
plasm of the common epithelial type are rare and not well
described in the medical literature. The first series of cases
was reported in 1986 by Young and Scully, in which 3 orig-
inal cases and 11 reviewed previous cases were documented
(4). Serous-type tumors are the most predominant among
common ovarian-type epithelial tumors arising in the testis,
and other types, including Brenner and mucinous tumors,
reportedly occur (5). Common ovarian-type testicular tumors
are usuallybenign or of
Endometrioid carcinoma of the testis is extremely rare and
has not yet been reported.
Although the mean age of patients with common
ovarian-type testicular tumors is 56 years (14–77 years)
(6), patients who developed the disease in childhood have
also been reported. The most common clinical presen-
tation is an indolent testicular mass, which cannot be
clinically and completely distinguished from other neo-
plasms. The tumors are usually treated by orchiectomy
alone and have a good clinical course without recurrence
or metastasis (7). The light microscopic features are iden-
tical to their ovarian counterpart, showing a papillary
pattern with mild atypia and microstromal invasion (8). In
addition, the present case shows a dense fibroblastic
stroma resembling an ovarian type (8).
common ovarian-type epithelial tumors have been studied
by immunohistochemistry profiling, electron microscopy
and DNA ploidy analysis. Immunohistochemical analysis
of endometrioid adenocarcinoma has proved to be identi-
cal to that of the ovarian counterpart with positivity to
cytokeratin, vimentin and absence of CEA. In addition,
expressions of ER and PgR are generally positive in
endometrioid adenocarcinoma but absent in serous carci-
noma (9). In the present case, immunohistochemical find-
ings, positive staining of ER and PgR, and negative
staining of CEA strongly support the diagnosis of endo-
The origin of common ovarian-type epithelial tumors in
the testis and paratesticular tissue remains unclear. Several
Figure 3. H&E staining of the surgical specimen (?200).
Figure 2. Gross appearance of a sliced section of the right testis.
Figure 1. Computed tomography (CT) reveals a cystic change in the right
Jpn J Clin Oncol 2011;41(5)675
by guest on July 30, 2015
possibilities have been suggested in previous literature. The Download full-text
most reasonable origin is remnants of mu ¨llerian ducts per-
sisting in the male appendix, testis or extratesticular scrotal
contents such as the epididymis, connective tissue between
the testis and epididymis and spermatic cord. Another possi-
bility is mu ¨llerian metaplasia of the tunica vaginalis.
Intratesticular tumors may develop from mesothelial
inclusions or represent monodermal teratoma (10). In the
present case, dense stroma resembling ovarian-type cortical
stroma was present in the tumor, further supporting a
mesothelial origin of these tumors. A testicular endometrioid
adenocarcinoma has a very peculiar microscopic finding.
The rarity of the histopathology in this location may lead to
difficulty in diagnosis, and the tumor may be confused with
other more aggressive tumors such as mesothelioma and
metastatic carcinoma (11). The histological distinction
between mesotheliomas and ovarian-type epithelial tumors
may be difficult, but it can be facilitated by the use of immu-
nohistochemistry. Calretinin, thrombomodulin and keratin 5/
6 were the best positive mesothelioma markers, and
MOC-31, B72.3, Ber-EP4, CA19-9 and leu-M1 (CD15) were
the best negative mesothelioma markers for differentiating
mesotheliomas from ovarian-type epithelial tumors (12).
Conflict of interest statement
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Figure 4. Immunohistochemical evaluation revealed tumor cells showing nuclear-specific staining for estrogen receptor (ER) (A) and progesterone receptor
676Intratesticular endometrioid papillary cystadenocarcinoma
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