Extrauterine low-grade endometrial stromal sarcoma with florid endometrioid glandular differentiation

Prognosis of uterine and extrauterine low-grade endometrial stromal sarcoma: an observational cohort study

OBJECTIVE

Little is known about the survival differences between uterine and extrauterine low-grade endometrial stromal sarcoma (LGESS). Survival outcomes, consisting of disease-free survivals and overall survivals (OS), were compared in these two entities.

METHODS

From February 2012 to June 2019, all primary LGESS cases and LGESS cases with first recurrence in the study center were reviewed. The clinicopathological characteristics and survival outcomes of extrauterine and uterine LGESS patients were compared for both primary and recurrent diseases.

RESULTS

During the study period, 143 patients with primary LGESS and 56 patients with recurrent LGESS were included and followed up to 1 June 2020, among whom 8 (5.6%) and 10 (17.8%) patients were identified as having extrauterine LGESS. Patients with primary and recurrent extrauterine LGESS had similar clinicopathological characteristics to those of patients with uterine LGESS. In primary or in recurrent LGESS cases, in univariate analysis, patients with uterine and extrauterine LGESS had similar disease-free intervals after the last treatment, and they also had similar OSs after the diagnosis. Ovarian preservation led to significantly increased recurrence for primary LGESS [hazard ratio (HR) 4.9, 95% CI: 2.3-10.1, P <0.001) and repeated recurrence for recurrent LGESS (HR 3.1, 95% CI: 1.3-7.3, P =0.009). Surgical treatment for recurrent LGESS decreased repeated recurrence after the first recurrence (HR 0.2, 95% CI: 0.1-0.7, P =0.006). No factors were found to be associated with the OS of primary or recurrent LGESS.

CONCLUSION

The clinical characteristics and survival outcomes of extrauterine LGESS are similar to those of uterine LGESS. Surgery is the treatment of choice for recurrent LGESS. Ovarian preservation is detrimental to disease-free survival but not to OS in both uterine and extrauterine LGESS.

Targeted RNA Sequencing Highlights a Diverse Genomic and Morphologic Landscape in Low-grade Endometrial Stromal Sarcoma, Including Novel Fusion Genes

Low-grade endometrial stromal sarcoma (LGESS) represents a morphologically and genetically heterogenous mesenchymal neoplasm. Previous work has shown that approximately half of LGESS are characterized by JAZF1::SUZ12 gene fusions, while a smaller proportion involves rearrangement of other genes. However, a subset of cases has no known genetic abnormalities. To better characterize the genomic landscape of LGESS, we interrogated a cohort with targeted RNA sequencing (RNA-Seq). Cases previously diagnosed as low-grade endometrial stromal neoplasia (n=51) were identified and re-reviewed for morphology and subjected to RNA-Seq, of which 47 were successfully sequenced. The median patient age was 49 years (range: 19 to 85). The most commonly detected fusions were JAZF1::SUZ12 (n=26, 55%) and BRD8::PHF1 (n=3, 6%). In addition to the usual/typical LGESS morphology, some JAZF1::SUZ12 fusion tumors showed other morphologies, including fibrous, smooth muscle, sex-cord differentiation, and myxoid change. Novel translocations were identified in 2 cases: MEAF6::PTGR2 and HCFC1::PHF1 . Ten tumors (21%) had no identifiable fusion, despite a similar morphology and immunophenotype to fusion-positive cases. This suggests that a subset of cases may be attributable to fusion products among genes that are not covered by the assay, or perhaps altogether different molecular mechanisms. In all, these findings confirm that RNA-Seq is a potentially useful ancillary test in the diagnosis of endometrial stromal neoplasms and highlight their diverse morphology.

Update on Endometrial Stromal Tumours of the Uterus

Endometrial stromal tumours (ESTs) are rare, intriguing uterine mesenchymal neoplasms with variegated histopathological, immunohistochemical and molecular characteristics. Morphologically, ESTs resemble endometrial stromal cells in the proliferative phase of the menstrual cycle. In 1966 Norris and Taylor classified ESTs into benign and malignant categories according to the mitotic count. In the most recent classification by the WHO (2020), ESTs have been divided into four categories: Endometrial Stromal Nodules (ESNs), Low-Grade Endometrial Stromal Sarcomas (LG-ESSs), High-Grade Endometrial Stromal Sarcomas (HG-ESSs) and Undifferentiated Uterine Sarcomas (UUSs). ESNs are clinically benign. LG-ESSs are tumours of low malignant potential, often with indolent clinical behaviour, with some cases presented with a late recurrence after hysterectomy. HG-ESSs are tumours of high malignant potential with more aggressive clinical outcome. UUSs show high-grade morphological features with very aggressive clinical behavior. With the advent of molecular techniques, the morphological classification of ESTs can be integrated with molecular findings in enhanced classification of these tumours. In the future, the morphological and immunohistochemical features correlated with molecular categorisation of ESTs, will become a robust means to plan therapeutic decisions, especially in recurrences and metastatic disease. In this review, we summarise the morphological, immunohistochemical and molecular features of ESTs with particular reference to the most recent molecular findings.

Endometrial Stromal Sarcoma Arising from Endometriosis

The malignant transformation of endometriosis is a very uncommon event but can occur in 0.7% to 1% of all cases. Any histological type of tumor found in the endometrium might also occur in endometriosis. Most malignant tumors that originate from endometriosis are endometrioid adenocarcinomas and also clear-cell type carcinomas. On the other hand, sarcomas, especially endometrial stromal sarcoma (ESS), are extremely unusual representing 12% of all cases. ESS is an uncommon neoplasm and accounts for 0.2% of the uterine malignances. Malignant tumors arising from endometriosis can derive from the uterine wall as well as from extra-uterine sites. The most frequent extrauterine location is the ovary (78.7%), followed by the pelvic peritoneum (5.7%), the rectovaginal septum (4.3%), the colon (4.3%) and the vagina (2%), representing the majority of extragonadal sites. ESSs arising from the extrauterine and extraovarian endometriosis sites in the absence of a primary uterine lesion are extremely rare and the treatment options are not clear. Surgical debulking seems to be the best treatment. Adjuvant therapy, such as radiation, hormonal therapy and chemotherapy are not yet proven to be effective. Molecular target therapy could be a future possibility of treatment.

A systematic review of English Medical Literature about incidence, treatment and prognosis of extrauterine ESS arising from endometriosis foci was performed. The selected articles on which this review is based are the following: 9 literature reviews, 8 retrospective studies, 7 case series, 1 prospective trial and 11 case reports.

Endometrial Stromal Sarcoma Arising in Colorectal Endometriosis

The malignant transformation of endometriosis is very uncommon. Whereas 75% of tumors arising from endometriosis arise in the ovary, location in extra-genital organs is rare and mesenchymal neoplasms are exceptional. A 47 year-old woman who underwent hysterectomy with bilateral salpingo-ooforectomy due to endometriosis 13 years before presented with abdominal pain. The magnetic resonance imaging (MRI) showed a 9.7×7.5 cm solid-cystic supravesical mass and a recto-vaginal tumor, as well as endometriotic nodules in the sigma, right parametrium and peritoneum that had significantly increased in size over a six months period. The patient underwent surgical resection of the masses. The histological study showed a low-grade endometrial stromal sarcoma (ESS) arising from endometriosis located at recotovaginal septum and affecting colonic wall and multiple peritoneal and pelvic implants. The patient received radiotherapy and aromatase inhibitors and is free of disease after a follow up of 2 years. Only 15 cases of ESS arising in endometriosis of the bowel have been reported. Tumor dissemination at diagnosis is unusual but does not imply a poor prognosis, as only one patient has died due to progression of the tumor. ESS should be included in the differential diagnosis of mesenchymal neoplasms in the intestine.

Endometrioid stromal sarcoma: a clinicopathologic study of 63 cases

Endometrioid stromal sarcoma (also known as extrauterine endometrial stromal sarcoma [EESS]) is an uncommon tumor that occurs in women over a wide age range. The extrauterine location, non-gynecologic symptoms and signs at presentation, and confounding histologic features can pose a diagnostic challenge. In this study, we present the clinicopathologic features of 63 cases of EESS seen during a period of 21 years at our institution. Clinical information and pathology material were reviewed. Ages ranged from 27 to 87 years (median: 50 years). The most common symptoms and signs were an abdominal or pelvic mass, pain, vaginal bleeding, and gastrointestinal symptoms. The tumor size ranged from 1.2 to 24.5 cm. The most common sites of involvement were the ovaries (25), bowel wall (28), abdomen/peritoneum (37), pelvis (20), and vagina (6). Multiple sites were involved in 40 cases. Forty-six of 49 tumors had a classic microscopic appearance, and 3 had dedifferentiation; in 20 cases, there was vascular invasion. Fibroma-like stroma was seen in 30, hyaline plaques in 23, sex cord elements in 11, smooth muscle differentiation in 4, and myxoid change in 4 cases. Endometriosis was noted in 30 cases. Immunohistochemical results included: CD10 positivity in 31, desmin positivity in 9 (focal), estrogen receptor positivity in 28, and progesterone receptor positivity in 33 cases. In 25% of cases, an initial diagnosis other than EESS was made: sex cord-stromal tumors (4), gastrointestinal stromal tumor (3), leiomyosarcoma (3), liposarcoma (1), müllerian adenosarcoma (1), synovial sarcoma (1), malignant peripheral nerve sheath tumor (1), small round blue cell tumor (1), and atypical stromal endometriosis (1). Primary treatment was cytoreductive surgery for 61 patients and hormonal therapy for 2 patients. Adjuvant treatment included hormonal therapy, chemotherapy, and radiation therapy. Follow-up (5 to 336 months) information was available for 53 patients: alive with no evidence of disease, 29; alive with disease, 15; and dead of disease, 9 (median period of 70 months from diagnosis to death). Thirty-three patients had recurrent disease, and 10 patients were lost to follow-up. EESS is commonly associated with endometriosis and tends to be indolent with a propensity for recurrence. Seven of 9 patients who died of the disease had bowel involvement, and 3 had tumors with dedifferentiation. Besides the latter, no other histologic finding correlated with the clinical behavior of these tumors.

Pulmonary metastatic nodules of uterine low-grade endometrial stromal sarcoma: histopathological and immunohistochemical analysis of 10 cases

AIMS

To identify histopathological and immunohistochemical findings that aid diagnosis of metastatic endometrial stromal sarcoma (ESS) in small biopsy specimens of the lung.

METHODS AND RESULTS

We reviewed the histology of 46 lung nodules from 10 cases of pulmonary metastatic ESS. Biopsy sections were analysed by immunohistochemistry to highlight blood and lymphatic vasculature, and for expression of CD10 and oestrogen receptor (ER). Various histological changes were identified that could mislead in making a diagnosis on small biopsy samples: haemangiopericytomatous blood vessels (39%), absence of characteristic spiral arteriole-like vasculature (26%), intratumoral cysts formed by dilatation of airways (22%) or intratumoral myxoid change (11%), prominent interstitial collagen deposits (48%), foam cell infiltration (4%) and smooth muscle differentiation (2%). Peribronchial/peribronchiolar distribution of tumour cells with juxtaepithelial growth was a frequent feature, observed in 59% of nodules. In two very small nodules the lesion was barely recognizable histologically; tumour cells were detected only by expression of ER and CD10.

CONCLUSIONS

Combined staining for ER and CD10 can be helpful in avoiding an erroneous diagnosis. As lymphatics are not normally present in the juxtaepithelial bronchial/bronchiolar wall, juxtaepithelial tumour growth beneath the bronchial epithelium in early metastatic lesions indicates a haematogenous metastastic route through the bronchial artery.

Recent developments in uterine mesenchymal neoplasms

Smooth muscle and endometrial stromal tumours represent the two most common uterine mesenchymal neoplasms that may present diagnostic dilemmas for the practising surgical pathologist. Recent changes in morphological and staging criteria, as well as the discovery of new immunohistochemical markers, have improved the diagnosis and classification of these tumours. We highlight the difficulty in distinguishing tumour cell necrosis from infarct-type necrosis and the limited utility of p16 immunohistochemical expression in the diagnosis of leiomyosarcoma. We also discuss the controversial use of mitotic activity and necrosis as prognostic factors in endometrial stromal sarcomas. Emerging genetic information has also greatly expanded our understanding of 'sarcomagenesis' in both tumour types and may provide insight into potential therapeutic targets for the treatment of leiomyosarcoma and endometrial stromal sarcomas, harboring MED12 (mediator complex subunit 12) mutations and recurrent gene rearrangements, respectively. In this review, we discuss the core updates in the diagnosis and classification of uterine leiomyosarcomas and endometrial stromal sarcomas, highlighting new and important molecular genetic findings that may drive pathogenesis.

A case of extrauterine endometrial stromal sarcoma in the colon diagnosed three decades after hysterectomy for benign disease

Extrauterine endometrial stromal sarcoma (ESS) is rare and typified by delayed recurrence of primary ESS. Here, we report an unusual case of colonic ESS in a woman with a remote history of hysterectomy. An 80-year-old woman, with a history of hysterectomy and bilateral salpingo-oophorectomy for abnormal bleeding and endometriosis 37 years prior to presentation, was diagnosed with ESS in the colon. She was treated with laparoscopic low anterior resection, followed by megestrol acetate, and has been in remission for more than 4 years. This case highlights the rarity of extra-uterine ESS in the colon, especially in the absence of a known history of primary uterine ESS. The patient's history of endometriosis may have been a predisposing risk factor. ESS in the colon may be treated successfully with surgical resection and progestin therapy. Indefinite surveillance is recommended to monitor for late recurrences.

Extragenital endometrial stromal sarcoma arising in endometriosis

The diagnosis rate of deep pelvic endometriosis is increasing. Endometrial stromal sarcoma (ESS) is a rare neoplasm. Extragenital ESS is an extremely uncommon event. Very few cases of extragenital ESS have been reported to date. The diagnosis of this entity is very difficult in some instances. Knowledge about its management is also limited. In this paper, we review the current literature on the clinical management, histology, immunohistochemistry, treatment and outcome of ESS arising in pelvic endometriosis.

Endometrial/ioid Stromal Tumors and Related Neoplasms of the Female Genital Tract

Endometrial/ioid stromal tumors comprise a spectrum of mesenchymal neoplasms, ranging from benign to low-grade malignancy to undifferentiated sarcomas, which occur predominantly in the uterus but may rarely originate at extrauterine sites, most commonly in the ovary. These tumors and their morphologic variants are important to recognize as they often cause diagnostic difficulties. This review focuses on the diagnostic criteria and differential diagnosis, including the role of immunohistochemistry.

Pathology of uterine malignancies

This overview covers epithelial, stromal and mesenchymal malignancies of the body of the uterus, excluding the cervix. The distinction of type I and type II endometrial adenocarcinoma with the morphological variants of this tumour is discussed and some molecular aspects are explored. The concept of carcinosarcoma representing a metaplastic adenocarcinoma of the endometrium that behaves more like a carcinoma than a sarcoma is explained. Some types of mixed epithelial and stromal neoplasm are described and contrasted with carcinosarcoma. The concept of stromal sarcoma and high-grade uterine sarcoma is described and an outline of malignant smooth muscle tumours of the uterus includes a description of smooth muscle tumours of uncertain malignant potential and worrying benign smooth muscle lesions.

High Frequency of JAZF1-JJAZ1 Gene Fusion in Endometrial Stromal Tumors With Smooth Muscle Differentiation by Interphase FISH Detection

The most common cytogenetic alteration observed in low-grade endometrial stromal tumors (EST) is the t(7;17)(p15;q21) translocation, resulting in the fusion of the JAZF1 and JJAZ1 genes. By reverse-transcription polymerase chain reaction, the translocation has been detected overall in one-third of ESTs, but only rarely in its variants. The purpose of this study was to develop a fluorescence in situ hybridization assay for detection of this translocation using archival paraffin-embedded samples of ESTs with smooth muscle differentiation and to assess the nature of the smooth muscle component of these tumors. Representative paraffin blocks of 9 endometrial stromal nodules and 1 low-grade endometrial stromal sarcoma were collected for the study. In 1 case, the block selected also contained areas of sex cordlike differentiation. A fluorescence in situ hybridization probe set was designed to detect the t(7;17)(p15;q12) on tissue sections. Six out of 10 collected ESTs were assessable. Fusion signals were detected in 3 out of 6 cases (50%) in both the conventional endometrial stromal and the smooth muscle components of the tumors. The tumor sample with sex cordlike differentiation harbored the fusion signal in all the 3 components. Our results support the contention that the endometrial stromal and smooth muscle components of these tumors have the same origin, either from a common precursor cell with pluripotential differentiation or from endometrial stromal cells that have undergone smooth muscle metaplasia. Our results indicate that the detection of this chromosomal abnormality can be used to diagnose ESTs with smooth muscle differentiation when the smooth muscle component is predominant.

Unusual morphologic features of endometrial stromal tumors: a report of 2 cases

Endometrial stromal tumors with typical morphology usually do not pose diagnostic problems. However, the finding of unusual morphologic features may be misleading in the final interpretation of these tumors. Herein, we described two endometrial stromal sarcomas discovered in hysterectomy specimens of women 31 and 75 years of age. Features typical of endometrial stromal neoplasia were present in both cases. Additionally, in 1 case, extensive fatty metaplasia as well as smooth and skeletal muscle metaplasia were found; and in the second case, focal bizarre nuclei, smooth muscle differentiation, and fibrous change were present. The differential diagnosis in the first case included cellular intravenous leiomyomatosis/lipoleiomyomatosis with skeletal muscle differentiation; and in the second case, a cellular smooth muscle tumor with bizarre nuclei was considered.

Low-grade endometrial stromal sarcoma arising from sciatic nerve endometriosis

BACKGROUND

Endometrial stromal sarcoma arising from extrauterine endometriosis is a rare and not easily diagnosed tumor. We present a case arising from sciatic nerve endometriosis in a 50-year-old woman.

CASE

The patient had a long history of endometriosis and presented with a left buttock mass and motor deficit. Magnetic resonance imaging showed a large tumor of the sciatic nerve with pelvic extension. She underwent total hysterectomy, bilateral salpingo-oophorectomy, and excision of pelvic endometriotic pockets, allowing the diagnosis of low-grade endometrial stromal sarcoma arising from endometriosis. She received systemic chemotherapy, gonadotropin-releasing hormone agonist therapy, and palliative radiation therapy, but her disease progressed.

CONCLUSION

Aggressive endometriosis raises important diagnostic and therapeutic difficulties and may correspond to misdiagnosed rare malignant neoplasms, which should be treated.

Usefulness of immunohistochemistry in delineating renal spindle cell tumours. A retrospective study of 31 cases

AIMS

To assess the usefulness of immunohistochemistry in delineating tumour diagnoses on a series of morphologically diagnosed renal spindle cell tumours (RSCTs).

METHODS AND RESULTS

Formalin-fixed paraffin-embedded tissues from 31 morphologically diagnosed tumours were reinterpreted in light of newly obtained immunohistochemical information. By morphology, six had originally been classified as sarcomatoid carcinoma, five as spindle cell tumour (NOS), four as sarcoma (NOS), three as leiomyoma, three as leiomyosarcoma, and one each as fibrous polyp, hamartoma, neurilemmoma, mesoblastic nephroma, medullary fibroma, angiomyolipoma, haemangiopericytoma, malignant rhabdoid tumour, malignant Triton tumour, and carcinosarcoma. The application of immunohistochemistry verified the original diagnosis in 18 cases (18/31, 58%), confirming the diagnosis of sarcomatoid renal carcinoma (4/6), leiomyoma (2/3), leiomyosarcoma (3/3), sarcoma (NOS) (2/4), carcinosarcoma (1/1), malignant rhabdoid tumour (1/1), malignant Triton tumour (1/1), fibrous polyp (1/1), mesoblastic nephroma (1/1), hamartoma (1/1), and angiomyolipoma (1/1). Different tumour designations were suggested in 13 cases (13/31, 42%), including carcinosarcoma, sarcoma (NOS), leiomyosarcoma, solitary fibrous tumour, monomorphic/biphasic angiomyolipoma, endometrial stromal tumour, and congenital mesoblastic nephroma.

CONCLUSIONS

Our data indicate that although morphology is most important in formulating the initial differential diagnosis, the addition of immunohistochemistry is vital in arriving at the correct classification of RSCTs.

Molecular Detection of JAZF1-JJAZ1 Gene Fusion in Endometrial Stromal Neoplasms with Classic and Variant Histology

Endometrial stromal tumors (ESTs), including low-grade endometrial stromal sarcomas (LGESSs) and endometrial stromal nodules (ESNs) of classic histology, exhibit characteristic morphologic features and contain the nonrandom t(7;17)(p15; q21), which results in the fusion of two novel genes, JAZF1 and JJAZ1. ESTs may pose diagnostic challenges when they involve extrauterine sites, present as metastases, or display variant histologic appearances. The aim of this study was to evaluate the frequency of the JAZF1-JJAZ1 gene fusion among primary uterine, metastatic, and primary extrauterine ESTs of various histologic types and its role as a possible diagnostic adjunct. Using a nonnested reverse transcriptase-polymerase chain reaction approach, we assayed for JAZF1-JJAZ1 gene fusion transcripts in 10 cases with available fresh-frozen tissue. These included five primary uterine (two classic, one mixed smooth muscle, and one epithelioid LGESS; one classic ESN), four metastatic (two fibromyxoid, one classic, and one epithelioid LGESS), and one extrauterine (classic LGESS) tumor. The same primer set and assay conditions were used on five additional paraffin-embedded cases with adequate RNA, including three primary uterine (one fibromyxoid and one mixed smooth muscle LGESS; 1 mixed smooth muscle ESN) and two intraabdominal recurrent (two mixed smooth muscle LGESSs) ESTs. Two cellular leiomyomas and one ESS cell line (ESS-1) without the t(7;17) at the cytogenetic level were run in parallel as controls. JAZF1-JJAZ1 gene fusion transcripts were detected in five (33%) of 15 ESTs, including three of eight primary uterine, one of four metastatic, one of one extrauterine, and none of two recurrent cases. Most ESTs of classic histology showed evidence of JAZF1-JJAZ1 fusion (4 of 5 cases), whereas only one mixed smooth muscle ESN of 10 variant cases was positive. Positivity for JAZF1-JJAZ1 fusion transcripts was found in four of 10 fresh-frozen samples and in one of five paraffin-embedded ESTs. The control specimens were all negative. In conclusion, our data suggest that ESTs are genetically heterogeneous, with the prevalence of the JAZF1-JJAZ1 fusion being highest among ESTs of classic histology. Hence, the diagnostic utility of a JAZF1-JJAZ1 fusion transcript assay in ESTs may be limited to the classic histologic subset.

Parenchymatous pulmonary endometriosis – metastases of a low-grade endometrial stromal sarcoma?

Based on the data of a case of parenchymatous endometriosis of the lung in which three and a half years later a low-grade endometrial stromal sarcoma of the uterus was diagnosed the origin of this disease is discussed. The follow up of this patient gave the impression that the pulmonary nodules were early metastases of low-grade endometrial stromal sarcoma, which was initially not detected in the routine gynecologic examination. Furthermore, as histological and immunohistochemical examinations are not sufficient to distinguish reliable between endometriosis of the lung and pulmonary metastases from low-grade endometrial stromal sarcoma. In literature, in none of the few cases of parenchymatous pulmonary endometriosis a hysterectomy was performed to exclude a low-grade endometrial stromal sarcoma. Thus, parenchymatous pulmonary endometriosis nodules might be metastases and their occurrence should cause the treating physician to consider a distant metastatic spread from low-grade endometrial stromal sarcoma.