Metastatic low-grade endometrial stromal sarcoma of uterus presenting as a primary pancreatic tumor: case presentation and literature review

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.

Utero-ovarian low grade endometrial stromal sarcoma, a case report

INTRODUCTION

Endometrial stromal sarcoma (ESS) is a rare malignancy of uterine in middle aged women. There are numerous subtypes for ESS which share the same clinical picture of uterine bleeding and pelvic pain. Consequently, diagnosis and treatment modalities of LG-ESS with metastasis are challenging. However, both molecular and immunological study of samples can be useful.

CASE PRESENTATION

In this case study, we report a 52-year-old woman presenting with the chief complaint of unusual uterine bleeding. There was no specific finding in her past medical history. The CT study revealed enlarged bilateral ovary with a significantly large left ovarian mass and suspicious mass in uterus. By the diagnosis of ovarian mass, patient went under total abdominal hysterectomy with bilateral salpingo-oophorectomy (BSO), greater omentectomy, and appendectomy followed by post-op hormone therapy. Her follow-up was uneventful. The IHC and pathological study of samples revealed incidental LG-ESS uterus mass with metastasis to ovaries despite her primary diagnosis.

DISCUSSION

LG-ESS has low metastasis rate. Surgical modalities and neoadjuvant therapies are recommended base on the stage of ESS. In the following study, we represent a case of incidental LG-ESS with bilateral ovarian invasion who was initially diagnosed as an ovarian mass.

CONCLUSION

Our patient was successfully managed by surgical intervention. Despite scarcity of LG-ESS, it is advised to consider LG-ESS as a differential diagnosis in management of patients with a uterus mass with bilateral ovarian involvement.

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.

Low-grade endometrial stromal sarcoma: A Turkish uterine sarcoma group study analyzing prognostic factors and disease outcomes

OBJECTIVE

To investigate factors associated with refractory disease, recurrence, or death as well as disease-free survival (DFS) and overall survival (OS) in low-grade endometrial sarcoma (LGESS).

METHODS

A multi-institutional, retrospective study was conducted in a total of 124 patients, who received a curative-intent surgery. The exclusion criteria were as follows: i) history of any other invasive disease; ii) neoadjuvant therapy; iii) fertility sparing surgery; iv) a different diagnosis after review of the slides.

RESULTS

All patients underwent hysterectomy, 96% had bilateral salpingo-oophorectomy, and 65% had lymphadenectomy. Twelve (14.8%) of 81 patients undergoing lymphadenectomy had lymph node (LN) metastasis. Of those, 8 (9.8%) had pelvic LN metastasis whereas 4 (5.6%) had isolated paraaortic LN metastasis. Six of 8 (75%) patients with positive pelvic LNs had concurrent paraaortic LN metastasis. Among 124 patients, 3 patients (2.4%) had refractory disease following primary therapy. During a median follow-up of 45.5 months, 27 (22.3%) of 121 patients who achieved complete remission after primary therapy developed recurrence, and 10 patients (8.1%) died of disease. The 3-year DFS and OS were 76.9% and 93.8%, respectively. Stage was the sole independent prognostic factor in the whole cohort. When analyzing factors within subgroups of stage I and stage ≥II, there was no significant prognostic factor for stage I; however, lymphadenectomy and adjuvant chemotherapy were significantly associated with disease outcomes for stage ≥II. While lymphadenectomy was related with improved DFS, chemotherapy was associated with poor DFS and OS.

CONCLUSION

The risk of LN metastasis at pelvic as well as paraaortic lymphatic basins is not negligible to omit lymphadenectomy in stage ≥II LGESS. Moreover, lymphadenectomy provides significant DFS advantage in patients with extrauterine disease.

Low-grade extrauterine endometrial stromal sarcoma of the peritoneum: A case report and literature review

Endometrial stromal sarcoma (ESS) is an uncommon mesenchymal tumor that accounts for less than 1% of all primary uterine malignancies and extrauterine endometrial stromal sarcoma (EESS) is even rarer. We report the case of a 75-year-old woman with an abdominal tumor and multiple peritoneal implants. Histological analysis of the surgical specimens showed bland cellularity resembling normal endometrial stroma. The diagnosis of a low-grade EESS was confirmed by immunophenotypic findings and demonstration of JAZF1 translocation. After extensive sampling, no evidence of endometriosis was found. Our case showed atypical aggressive behavior and we discuss the possible influence of the high mitotic count (8/10 HPFs) in some areas of the tumor, the multifocality of the abdominal implants and the postmenopausal status of the patient. The unusual clinical presentation and extrauterine location of such a rare tumor were challenging implying a wide range of differential diagnosis. The correlation of morphological, immunohistochemical and molecular findings was necessary to arrive at the correct diagnosis.