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Gynecologic Oncology 93 (2004) 546–549

Case Report

Retroperitoneal mullerian carcinosarcoma associated with

endometriosis: a case report

Christine Booth,a Christopher M. Zahn,b,* John McBroom,a and G. Larry Maxwella

aDepartment of Obstetrics and Gynecology, Walter Reed Army Medical Center, Washington, DC, USAbDepartment of Obstetrics and Gynecology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, USA

Received 3 September 2003

Abstract

Background. Mixed mullerian tumors are rare malignancies of the female genital tract and extremely uncommon in extragenital sites.

Case. A 71-year-old woman presented with a 3-month history of left-sided pelvic pain. Significant history included total abdominal

hysterectomy and bilateral adnexectomy performed 19 years earlier for benign indications; she had no history of endometriosis. Bimanual

exam and pelvic ultrasonography demonstrated a 6 � 5 � 6 cm complex mass in the left pelvis. Exploratory laparotomy revealed a

retroperitoneal mass encasing the left ureter. The mass was debulked, necessitating resection of the distal ureter and ureteroneocystotomy.

Histopathology demonstrated carcinosarcoma associated with endometriosis.

Conclusion. Extragenital carcinosarcoma is a rare malignancy, with only one well-documented case associated with peritoneal

endometriosis. We report a case of an extragenital retroperitoneal carcinosarcoma associated with endometriosis.

D 2004 Elsevier Inc. All rights reserved.

Keywords: Carcinosarcoma; Endometriosis; Retroperitoneum

Introduction

Carcinosarcoma is a rare tumor, occurring in only 2–3%

of uterine malignancies and in less than 1% of ovarian

cancers [1–3]. Extragenital carcinosarcoma, especially

occurring in the retroperitoneum, is extremely uncommon,

and carcinosarcoma arising in endometriosis has been well

documented in only one case report [4]. We describe a case

of an extragenital retroperitoneal carcinosarcoma associated

with endometriosis.

Case report

A 71-year-old woman using estrogen replacement ther-

apy (conjugated estrogens, 1.25 mg per day) presented with

a 3-month history of left lower quadrant abdominal and

pelvic pain. Past history was significant for a total abdom-

0090-8258/$ - see front matter D 2004 Elsevier Inc. All rights reserved.

doi:10.1016/j.ygyno.2004.01.018

* Corresponding author. Department of Obstetrics and Gynecology,

Uniformed Services University of the Health Sciences, 4301 Jones Bridge

Road, Bethesda, MD 20814-4799. Fax: +1-301-295-1988.

E-mail address: czahn@usuhs.mil (C.M. Zahn).

inal hysterectomy and bilateral salpingo-oophorectomy per-

formed at age 52 for symptomatic fibroid uterus. Per report,

there were no pathologic abnormalities of the tubes and

ovaries and the uterus was only notable for leiomyomata.

The women also underwent posterior colporrhaphy 2 years

before the current presentation and a rectovaginal fistula

repair 1 year after the colporrhaphy. Importantly, she had no

history of endometriosis.

Physical exam demonstrated a slender woman with no

significant findings except for the pelvic examination, which

revealed amass at the vaginal cuff extending from themidline

to the left lower quadrant. There was no inherent bowel lesion

palpated on rectovaginal exam and colonoscopy revealed no

intrinsic bowel lesion. Ultrasound and computerized tomo-

graphic scan demonstrated a solid and cystic mass in the left

pelvis measuring 6� 5� 6 cm. Magnetic resonance imaging

revealed a retroperitoneal mass, with compression of the left

ureter and resultant hydronephrosis (Figs. 1a and b). A renal

scan demonstrated left renal pelvis dilation, decreased perfu-

sion of the left kidney, and completed absence of drainage

into the left renal collecting system.

The woman subsequently underwent exploratory lapa-

rotomy with findings of a retroperitoneal mass encasing the

Fig. 1. Magnetic resonance imaging of the pelvic mass. (a) Cross section of

the pelvis demonstrating an irregular mass in the left pelvis, with deviation

of the bowel to the right anterior abdominal cavity. (b) T2 sagittal view

demonstrative of the probable retroperitoneal location of the mass, with

dilation of the ureter superior to the mass.

Fig. 2. Carcinosarcoma adjacent to endometriosis. (a) Low-power H&E

view demonstrating the tumor (primarily adenocarcinoma in the areas

associated with endometriosis) arising in an area of endometriosis. The

carcinoma is in the upper right aspect of the photo, with endometriosis and

surrounding fibrosis intimately associated with the carcinoma (40�). (b)

Medium-power H&E view of the carcinosarcoma, demonstrating the

epithelial component forming glandular structures adjacent to the

sarcomatous component (100�).

C. Booth et al. / Gynecologic Oncology 93 (2004) 546–549 547

distal left ureter. The surgical procedure included resection

of the pelvic mass and distal left ureter, left ureteroneocys-

totomy, psoas hitch procedure, omentectomy, and pelvic and

paraaortic lymph node sampling. The patient recovered

without difficulty and was discharged after 5 days.

Pathologic findings demonstrated the mass to measure

9 � 7 � 6.5 cm, with a weight of 46 g. The mass contained

both solid and cystic components; the cystic structures

contained a brown, mucoid fluid and numerous thick

excrescences. Histologic findings demonstrated carcinosar-

coma (homologous type) intimately associated with endo-

metriosis (Figs. 2a and b). The epithelial component

consisted of a Grade II endometrioid adenocarcinoma and

the sarcomatous component was a stromal sarcoma. The

tumor mass with associated dense fibrosis surrounded the

ureter; however, the ureter itself was uninvolved; there was

no mucosal abnormality identified in the ureteral segment.

There was no lymph vascular invasion identified, and the

omentum, peritoneal biopsies, and all nodes were negative

for metastases.

Immunohistochemical staining for cytokeratin demon-

strated diffuse strong staining of the epithelial component

(Fig. 3), and staining with vimentin demonstrated rare

staining of the epithelial component and diffuse strong

staining of the mesenchymal component. This immunohis-

tochemical staining pattern confirmed the biphasic cell

population of the tumor. Additional immunohistochemical

stains for muscle-specific actin and desmin, which are

positive in sarcomas with smooth muscle differentiation,

were negative. Immunohistochemical staining for CD-10

was strongly positive in several foci of the sarcomatous

component, which is consistent with a stromal sarcoma.

Additionally, immunohistochemical staining of the epithe-

lial component of the tumor was positive for CK7 but

negative for CK20, which supports mullerian origin.

Fig. 3. Immunohistochemical stain for cytokeratin demonstrating strong

staining of the epithelial component and lack of staining of the sarcomatous

component (100�).

C. Booth et al. / Gynecologic Oncology 93 (2004) 546–549548

Postoperatively, the woman received external beam

radiation therapy to the pelvis. A total dose of 5040 cGy

was well tolerated. Currently, at 8 months since the

surgery, the woman is functioning well without evidence

of recurrence.

Discussion

Extragenital carcinosarcoma is extremely uncommon,

with approximately 25 reported cases [5]. It has been

previously described to occur on pelvic peritoneal surfaces,

including visceral peritoneum of the cecum and rectosig-

moid colon, and parietal peritoneum of the abdomen and

pelvis [4,6–8]. Of these extragenital sites, the retroperito-

neum is the most rare, with only three previously reported

cases [5,9,10]. Notably, endometriosis was not present in

any of these three reports of retroperitoneal carcinosarcoma.

Malignancy arising in endometriosis is well documented,

with over 200 reported cases. First described by Sampson in

1925, the criteria used to establish malignancy arising in

ovarian endometriosis include the following: (a) presence of

benign endometriosis, (b) endometriosis present in close

proximity to malignancy, and (c) malignant tissue histology

consistent with endometriotic origin and no suggestion of

metastasis [11,12]. Approximately 80% of malignancies

associated with endometriosis are identified in the ovary,

and the vast majority of those (approximately 80%) are

adenocarcinomas [12]. In general, sarcomas and carcinosar-

comas associated with endometriosis are uncommon (ap-

proximately 11%); however, when found in extragonadal

sites, sarcomas and carcinosarcomas may be identified in as

many as 25% of endometriosis-associated malignancies

[12].

Carcinosarcoma occurring in endometriosis is therefore

very rare and when present is most commonly identified in

the ovary. Extragenital carcinosarcoma associated with

endometriosis is extremely uncommon. Campins et al. [6]

described a homologous carcinosarcoma found in a pelvic

mass in a patient with a prior history of endometriosis.

However, histologic evaluation of the mass did not reveal

evidence of endometriosis. Slavin et al. [8] described a

sigmoid colon mass, of which pathologic evaluation dem-

onstrated carcinosarcoma with a focus of endometriosis

bordering the neoplasm. However, the patient had a history

of endometrial cancer diagnosed 2 years before the discov-

ery of the mass. Thus, the origin of the tumor is less certain,

as metastasis and recurrence from the previous endometrial

cancer may have developed. DeLaPava et al. [13] reported a

case of carcinosarcoma associated with endometriosis,

though critical review of the histopathologic description of

the tumor revealed only a sarcomatous component. Ober

and Black [14] described a homologous carcinosarcoma

arising near an area, which was described as an atypical

pattern of endometriosis. However, ‘‘atypical endometri-

osis’’ is not a consistently defined entity and is therefore

difficult to ascertain whether this neoplasm was truly

associated with endometriosis. Chumas et al. [4] described

a carcinosarcoma arising from endometriosis in a patient

with a previous supracervical hysterectomy and bilateral

salpingo-oophorectomy for benign indications. The tumor

was located on the right pelvic sidewall and originated from

the serosa of the rectosigmoid colon. This is the only well-

documented case of extragenital carcinosarcoma arising in

endometriosis, and the tumor was located on a peritoneal

surface.

In our case, the neoplasm, which was consistent with a

gynecologic origin based on histology and immunohisto-

chemical staining, was found in a retroperitoneal mass and

was clearly associated with endometriosis. Additionally, this

case fulfills Sampson’s [11] previously described criteria for

malignancy arising in endometriosis. The etiology of the

lesion might involve several theories, including develop-

ment of endometriosis from a mullerian rest or peritoneal

mesothelium with subsequent development of carcinosarco-

ma. Alternatively, it is possible that endometriosis and the

subsequent carcinosarcoma developed in an ovarian rem-

nant adherent to the pelvic sidewall. However, the present

pathologic specimen contained no normal-appearing ovarian

tissue, and there were no apparent conditions at the time of

the woman’s prior surgery, such as endometriosis or adhe-

sions, that might increase the risk of leaving an ovarian

remnant. Extraovarian endometriosis is well documented;

thus, spontaneous origin from peritoneal mesothelium with

further retroperitoneal development or a true retroperitoneal

origin of endometriosis with subsequent development of

carcinosarcoma is the most likely etiology. Interestingly, this

patient had a history of postmenopausal estrogen use;

unopposed estrogen use has been suggested to have a

possible association with the development of endometri-

osis-associated malignancy [15,16].

Although uncommon, an extragenital malignancy, possi-

bly associated with endometriosis, should be considered in

C. Booth et al. / Gynecologic Oncology 93 (2004) 546–549 549

the differential diagnosis in any woman with a pelvic mass,

even in those who have undergone prior hysterectomy and

bilateral adnexectomy. These malignancies are more likely

to be adenocarcinomas; however, sarcomas and carcinosar-

comas must also be considered.

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