Indian Journal of Pathology and Microbiology

: 2014  |  Volume : 57  |  Issue : 3  |  Page : 447--449

Primary extrauterine endometrial stromal sarcoma: Located in pelvic and abdominal tissue and arising in endometriosis

Tanushree Ghosal1, Arunava Roy2, Susy Kurian1,  
1 Department of Pathology, Tata Medical Center, Kolkata, India
2 Department of Gynaecology, Tata Medical Center, Kolkata, India

Correspondence Address:
Tanushree Ghosal
MD, DNB, Fellow, Oncopathology, LVM-14A, ABL Township, Durgapur - 713 206, West Bengal


Primary extrauterine endometrial stromal sarcoma is a rare tumor and it is infrequently associated with endometriosis. We are reporting a case of this unusual tumor in a 42-year-old female who presented with multiple nodules of tumor in the abdomen and pelvis and with metastases in para-aortic lymph nodes. The right parametrium, in addition, had a focus of endometriosis, which was contiguous with the tumor, confirming its origin.

How to cite this article:
Ghosal T, Roy A, Kurian S. Primary extrauterine endometrial stromal sarcoma: Located in pelvic and abdominal tissue and arising in endometriosis.Indian J Pathol Microbiol 2014;57:447-449

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Ghosal T, Roy A, Kurian S. Primary extrauterine endometrial stromal sarcoma: Located in pelvic and abdominal tissue and arising in endometriosis. Indian J Pathol Microbiol [serial online] 2014 [cited 2022 Oct 4 ];57:447-449
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Primary extrauterine endometrial stromal sarcoma (ESS) is an unusual tumor and only about 80 cases have been reported thus far in literature. [1],[2] The largest series reported was from the M D Anderson Cancer Center, Texas, in 2013. That was a case series of 63 cases collected over a period of 21 years. [1] In that series the most common site of involvement was the abdominal peritoneum, followed by the bowel wall, the ovaries, and the pelvis. Half of those cases were associated with endometriosis.

Most case reports however are those of ESS of the bowel wall, some of which are associated endometriosis. [2],[3],[4],[5],[6] We are reporting this as an unusual case where pelvic and abdominal sites were the locations of multiple primary extrauterine ESS and where there was a site of endometriosis contiguous with the tumor in the right parametrium, clearly indicating the origin of the tumor.


A 42-year-old female presented at another hospital having noticed a mass on the anterior abdominal wall for about a month. She had borne two children and had two other pregnancies, which had ended in abortion. Ultrasonography of the abdomen at that hospital was reported as showing a cystic mass of 11 mm × 11 mm size with thick hyperechoic walls and echogenic mural nodules, located in the midline of the anterior abdominal wall. Ultrasonography then also reportedly showed an enlarged uterus and 8 mm thick endometrium. Both ovaries were normal in size and echogenicity.

A computed tomography scan of the brain and chest X-ray were done at the same admission and were reported as normal.

The cyst on the anterior abdominal wall was excised at that hospital, and the specimen blocks were sent to this laboratory for an opinion. In this hospital, we concurred with the diagnosis of ESS made earlier. The patient was referred here for further treatment.

At this hospital, a magnetic resonance imaging scan of the abdomen demonstrated multiple well-defined enhancing rounded nodular lesions in the pelvic cavity and pouch of Douglas. The uterus was bulky and free of tumor. The cervix and vagina appeared normal.

The patient underwent a total abdominal hysterectomy along with removal of all the pelvic and abdominal lesions and resection of pelvic and para-aortic lymph nodes.

The specimens received in this laboratory consisted of the uterus with the adnexae. On inspection there were multiple nodular firm white masses ranging in size from 0.7 cm to 2.8 cm in diameter [Figure 1] which were present in both parametria. When sectioned the nodules had homogeneous white and soft surfaces.{Figure 1}

Similar nodules from the omentum, sigmoid mesentery and transverse mesocolon were also sent separate from the above. There were no intraparenchymal tumors in both ovaries, uterus and cervix on gross examination. The myometrium was thick and measured 2.5 cm.

On histological examination, the nodules were found to be composed of short fascicles of spindle-shaped cells with uniform small round to oval nuclei and rare mitoses [Figure 2]a. Small prominent arterioles were scattered among the stromal cells [Figure 2]b. A focus of endometriosis was intimately associated with the tumor in the right parametrium [Figure 2]a. The tumor cells stained positively on immunohistochemistry for CD10 [Figure 2]c and progesterone receptor [Figure 2]d, confirming the morphological diagnosis. The staining was diffuse and strong.{Figure 2}

The right ovary was found to have a microscopic focus of tumor. The original biopsy site on the anterior abdominal wall had a residual focus of tumor. Multiple random sections of the uterine wall on histopathology revealed extensive adenomyosis, but no evidence of ESS. Metastatic deposits of ESS were present in two of the seven para-aortic lymph nodes.

On the 8 th postoperative day, the patient developed a rupture at the rectosigmoid junction from where adherent tumor was previously removed. This site was surgically repaired, and the patient recovered and was discharged on the 15 th day after surgery.


This is an unusual case of ESS. It spared the uterine wall but arose at various sites in the pelvic and abdominal peritoneum. One tumor in the right parametrium clearly demonstrated its origin from endometriosis.

It is estimated that only 0.7-1% of women with endometrosis develop malignant neoplasms and the most frequently involved transformation site is the ovary. [7] Most malignant tumors, which arise from endometriosis are usually endometrial adenocarcinomas. The development of ESS is rare. [4] In the case series of Yantiss et al. on gastrointestinal endometriosis, only one case of ESS occurred among the 17 cases studied. [2] Subsequently, other case reports of gastrointestinal ESS complicating endometriosis have appeared. [3],[4],[5],[6]

Two cases in literature were correctly diagnosed several years after hysterectomy in postmenopausal women, both of whom had a past history of endometriosis. [3],[6] One patient had an Estraderm patch as estrogen replacement therapy and it was speculated that this may be the cause of development of ESS in the postmenopausal state. [2],[5]

The largest series of extrauterine ESS reported in recent literature is from the M D Anderson Cancer Center, Texas from where 63 cases were collected over a 21-year period. [1] Most of the 63 cases were located in the abdominal peritoneum and were present at multiple sites, as seen in this case. The study showed that half the cases of ESS had demonstrable endometriosis to corroborate the diagnosis.

Endometrial stromal sarcoma can be a diagnostic challenge when encountered in the abdominal peritoneum. ESS should enter the differential diagnoses along with common spindle cell tumors of the abdominal peritoneum such as GIST and leiomyosarcoma. Immunocytochemistry plays an important role in distinguishing these tumors.

Complete surgical removal of ESS is the treatment of choice, as has been performed in this case. However, the metastasis of ESS to para-aortic lymph nodes, would usually predict an unfavorable outcome. Treatment of metastatic ESS with adjuvant hormonal therapy has been shown to be effective. [6]


This case is being presented to emphasize the rarity of primary extrauterine ESS occurring in pelvic and abdominal soft tissue and to corroborate its association with endometriosis. ESS should always be part of the differential diagnoses of any pelvic/abdominal spindle cell tumor.


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