Endometrial stromal tumors: A clinico-histomorphological spectrum of endometrial stromal tumors with review of literature

BACKGROUND

Endometrial stromal tumors (ESTs) are rare subset of mesenchymal uterine neoplasms. There are heterogeneous morphological, immunohistochemical, and genetic features. Approximately 50% of ESTs occur in perimenopausal women. In 2020, WHO sub-categorized ESTs into four groups: endometrial stromal nodule (ESN), low-grade endometrial stromal sarcoma (LGESS), high-grade endometrial stromal sarcoma (HGESS), and undifferentiated uterine sarcoma (UUS).

OBJECTIVE

To review the morphological spectrum of endometrial stromal tumors.

METHOD

This retrospective study reviewed the histomorphological features of 15 endometrial stromal tumors with respect to atypia, necrosis, mitosis, collagen bands, whorling around vessels, myometrial invasion, and inflammatory cells. Immunohistochemistry markers (CD10, SMA, and ER) along with special stains (Masson's trichrome, toluidine blue) were also studied.

RESULTS

The age of the patients ranged from 32 to 60 years. Three patients were postmenopausal. The most common presenting symptom was vaginal bleeding. Five patients were operated with a clinical diagnosis of uterine fibroid. One patient presented with prolapse with no other complaint. All the 15 patients had total abdominal hysterectomy and salpingo-oophorectomy. One case showed necrosis, eight cases showed collagen bands, all the 15 cases showed whorling around vessels, one case showed vascular emboli, and seven cases showed inflammatory cells. In low-grade cases, one case showed focal atypia and one case showed focal coagulative necrosis indicating infarction. Thirteen cases were LGESS, and one case of ESN and HGESS. All cases were positive for ER and CD10.

CONCLUSION

Endometrial stromal tumors demonstrate extensive permeation of the myometrium as irregular islands with frequent vascular invasion, whorling around vessels, collagen bands, and inflammatory cells. All these features should be observed thoroughly on microscopy by pathologists to clearly differentiate the low-grade and high-grade endometrial stromal tumors, and to understand the overlapping gray areas morphologically as it affects the prognosis of the patient.

An Unusual Endometrial Stromal Neoplasm With JAZF1-BCORL1 Rearrangement

Endometrial stromal tumors represent the second most common category of uterine mesenchymal tumors. Several different histologic variants and underlying genetic alterations have been recognized, one such being a group associated with BCORL1 rearrangements. They are usually high-grade endometrial stromal sarcomas, often associated with prominent myxoid background and aggressive behavior. Here, we report an unusual endometrial stromal neoplasm with JAZF1-BCORL1 rearrangement and briefly review the literature. The neoplasm formed a well-circumscribed uterine mass in a 50-yr-old woman and had an unusual morphologic appearance that did not warrant a high-grade categorization. It was characterized by a predominant population of epithelioid cells with clear to focally eosinophilic cytoplasm growing in interanastomosing cords and trabeculae set in a hyalinized stroma as well as nested and fascicular growths imparting focal resemblance to a uterine tumor resembling ovarian sex-cord tumor, PEComa, and a smooth muscle neoplasm. A minor storiform growth of spindle cells reminiscent of the fibroblastic variant of low-grade endometrial stromal sarcoma was also noted but conventional areas of low-grade endometrial stromal neoplasm were not identified. This case expands the spectrum of morphologic features seen in endometrial stromal tumors, especially when associated with a BCORL1 fusion and highlights the utility of immunohistochemical and molecular techniques in the diagnosis of these tumors, not all of which are high grade.

ZC3H7B-BCOR Fusion High-grade Endometrial Stromal Sarcoma With Morphologic Features of Low-grade Endometrial Stromal Sarcoma. A Case Report and Review of Literature

High-grade endometrial stromal sarcomas with ZC3H7B-BCOR fusion are rare. They are predominantly located in the endomyometrium, with morphologic features characterized as haphazardly arranged fascicles of spindle cells with mild to moderate atypia, abundant myxoid matrix, high mitotic index, and tongue-like/pushing patterns of myometrial invasion. Furthermore, conventional or variant low-grade endometrial stromal sarcomas are often not present. Clinically, they present at a higher stage and are associated with worse prognosis compared with low-grade endometrial stromal sarcoma. Given the limited number of reported cases, we describe the case of a ZC3H7B-BCOR fusion high-grade endometrial stromal sarcoma initially diagnosed on the hysterectomy specimen as low-grade endometrial stromal sarcoma based on an endometrial stromal tumor showing tongue-like myometrial and lymphovascular invasion, minimal cytologic atypia, low-mitotic activity (0-1/10 high-power field), round/spindle cell component and immunohistochemical stain results (positive for CD10, estrogen receptor, progesterone receptor, and focally positive for cyclin D1). At the time of pathologic diagnosis, she was Stage Ia and managed conservatively. Subsequent molecular analysis revealed a ZC3H7B (exon 10)- BCOR (BCL-6 corepressor) (exon 7) gene fusion. On follow-up, she showed no evidence of disease at 37 months from the time of diagnosis. This case report expands the morphologic spectrum of ZC3H7B-BCOR fusion high-grade ESS, which includes an intramural location, morphologic and immunophenotypic features similar to LG-ESS, as well as the presence of round and spindle cell components. This case also underscores the value of molecular analysis in the proper classification of ESS.

[Endometrial and other rare uterine sarcomas : Diagnostic aspects in the context of the 2020 WHO classification]

Uterine sarcomas are a heterogeneous group of rare malignancies. Mostly (40-50%), they are leiomyosarcomas, followed by endometrial stromal sarcomas (ESS), low-grade (LG) and high-grade (HG), as well as undifferentiated sarcoma of the uterus (UUS) and adenosarcomas (AS). Other, non-organ-specific tumours such as NTRK-rearranged spindle cell neoplasia, perivascular epithelioid cell tumour (PEComa) and inflammatory myofibroblastic tumour (IMT) are extremely difficult to differentiate.In the most recent WHO classification, endometrial stromal tumours are subdivided as follows: benign, expansively growing endometrial stromal nodule (ESN) with sharp demarcation, the histologically similar-looking LG-ESS with infiltrative growth, the highly malignant HG-ESS and, as a diagnosis of exclusion, the highly aggressive UUS lacking specific lines of differentiation. LG-ESS can be differentiated from HG-ESS in most cases histomorphologically and immunohistochemically, but molecular investigations are necessary in individual cases. HG-ESS can be divided into 4 subtypes (YWHAE/NUTM2 fusion low-grade component, YWHAE/NUTM2 fusion high-grade component, ZC3H7B-BCOR fusion or BCOR-ITD) on the basis of molecular findings. Prognostically unfavourable factors in AS are severe sarcomatous overgrowth, deep myometrial invasion, high-grade histology and lymphatic vessel invasion. Tumours with NTRK fusion are immunohistochemically positive for S100 and TRK. PEComas express cathepsin K and HMB45, as well as TFE3 when translocation is present. Almost every IMT shows an alteration in the ALK gene In the case of overlapping morphology and simultaneous therapeutic and prognostic relevance, it is becoming increasingly important to verify or confirm the suspected histomorphological diagnosis by immunohistochemical and possibly molecular investigations.

Analysis of diagnosis and treatment of complicated cervical severe adhesion atresia after removal of endometrial stromal nodule: A case report

RATIONALE

Endometrial stromal nodule (ESN) is a rare benign endometrial stroma tumor.Experiences are helpful for avoiding and treating similar postoperative complications (cervical adhesions and atresia).

PATIENT CONCERNS

When appearing in the cervical, this tumor can easily lead to complications after the surgical resection. The diagnosis and postsurgery complication of a young woman's ESN was reported here.

DIAGNOSES

The postoperative pathological diagnosis was ESN.

INTERVENTIONS

A 29-year-old young woman was diagnosed and treated for ESN in cervical parts with postsurgery complications of cervical complex adhesion atresia.

OUTCOMES

The complication was complex cervix adhesion atresia with very special imaging performance-the cervix and the palace imaged as "Twisted and Angled Staircase." This particular cervix adhesion was challenging for operation. We achieved a successful treatment through the carefully designed surgical procedure including the application of hysteroscopy and laparoscopy.

LESSONS

The lower uterine segment and cervix should be paid attention during suturing in this situation. Close and positive follow-ups should be planned after the endometrial stromal resection. The reconstruction of the tunnel is a solution for the problem of menstruation.

The application of next-generation sequencing-based molecular diagnostics in endometrial stromal sarcoma

AIMS

Endometrial stromal sarcomas (ESSs) are divided into low-grade and high-grade subtypes, with the latter showing more aggressive clinical behaviour. Although histology and immunophenotype can aid in the diagnosis of these tumours, genetic studies can provide additional diagnostic insights, as low-grade ESSs frequently harbour fusions involving JAZF1/SUZ12 and/or JAZF1/PHF1, whereas high-grade ESSs are defined by YWHAE-NUTM2A/B fusions. The aim of this study was to evaluate the utility of a next-generation sequencing (NGS)-based assay in identifying ESS fusions in archival formalin-fixed paraffin-embedded tumour samples.

METHODS AND RESULTS

We applied an NGS-based fusion transcript detection assay (Archer FusionPlex Sarcoma Panel) that targets YWHAE and JAZF1 fusions in a series of low-grade ESSs (n = 11) and high-grade ESSs (n = 5) that were previously confirmed to harbour genetic rearrangements by fluorescence in-situ hybridization (FISH) and/or reverse transcription polymerase chain reaction (RT-PCR) analyses. The fusion assay identified junctional fusion transcript sequences that corresponded to the known FISH/RT-PCR results in all cases. Four low-grade ESSs harboured JAZF1-PHF1 fusions with different junctional sequences, and all were correctly identified because of the open-ended nature of the assay design, using anchored multiplex polymerase chain reaction. Seven non-ESS sarcomas were also included as negative controls, and no strong ESS fusion candidates were identified in these cases.

CONCLUSIONS

Our findings demonstrate good sensitivity and specificity of an NGS-based gene fusion assay in the detection of ESS fusion transcripts.

Rapid enlargement of endometrial stromal sarcoma after uterine fibroid embolization for presumed adenomyosis: a case report and literature review

Uterine sarcomas have rarely been diagnosed after uterine artery embolization. It remains unclear whether the diagnostic work-up is required prior to such embolization to prevent a missed diagnosis of sarcomas and a delay in providing definitive treatment. Because of the rarity and heterogeneity of endometrial stromal neoplasms, little is known about their epidemiology, pathogenesis, and molecular pathology. The authors report a case of low-grade endometrial stromal sarcoma (ESS) diagnosed after uterine fibroid embolization. Although they performed laparoscopic biopsy of the rapidly growing uterine mass, they could not detect the ESS. Although rare, ESS should be considered in the differential diagnosis of uterine fibroid enlargement. It is essential to assess the risk of malignancy by taking into account the patient's clinical symptoms, results of the physical exam, and imaging findings prior to uterine artery embolization. Pathologic diagnosis should include an adequate biopsy sample and the use of molecular genetic testing.

[Uterine myoma in remnant cervix]

Parasitic myomas are rare and their ethiopathogenesis is uncertain. They may develop from a detached fibroid adhering to an extrauterine surface in order to obtain new blood supply. It has been stated that they form from uterine or myoma fragments left behind after morcellation in the abdominopelvic cavity and thus are called "iatrogenic". Surgeons must be aware of this recently reported complication related to the increasing number of laparoscopic procedures. Thorough inspection and washing of the abdominal cavity are recommended. A case of a patient with iatrogenic parasitic myomas, which appeared six years after a laparoscopic supracervical hysterectomy involving a morcellator, is reported.

Endometrial stromal tumours of the uterus: a practical approach using conventional morphology and ancillary techniques

Endometrial stromal tumours (ESTs) are diagnosed in most instances by light microscopy. Often, the greatest challenge is to distinguish between the different subtypes of these tumours. Furthermore, a handful of new or relatively new entities have been described in the literature, which may cause problems in the differential diagnosis; highly cellular leiomyoma is the most common. In addition, new antibodies have been developed to help in the distinction of ESTs from their mimics, as there are prognostic and therapeutic implications. A practical approach is provided for the diagnosis of ESTs on the basis of systematic assessment of histological and immunohistochemical parameters, and recent developments related to these tumours are highlighted.

Difficulties in Assessing the Depth of Myometrial Invasion in Endometrial Carcinoma

The depth of myometrial invasion (DMI) is one of the most important prognostic indicators and determinants of therapy in endometrial cancer. There are well-documented problems in recognizing DMI. We examined 100 previously diagnosed endometrioid endometrial carcinomas in hysterectomy specimens, reassessed DMI, and explored morphological features that complicated appraisal of myometrial invasion. The DMI was different from the original measurement in 29% of cases. Twelve percent of all cases (40% of cases with measurement discrepancies) involved differences in the assignment of invasion categories (noninvasive, < or =50% myometrial invasion, and >50% myometrial invasion). Nearly all endometrial cancers originally diagnosed as invasive were considered noninvasive on review. We examined whether the distribution of stromal metaplasia, noninvasive patterns (exophytic tumors, irregular endomyometrial junctions, and adenomyosis), and myometrial invasion patterns were different in cases with and without measurement discrepancies. Irregular endomyometrial junctions, exophytic tumors, and adenomyosis tended to coexist and were more common in the cases with DMI discrepancies. Although there seemed to be a relationship between smooth muscle metaplasia and exophytic tumors, it did not appear that smooth muscle metaplasia was significantly more common in cases with measurement difficulties. However, cases with extensive smooth muscle metaplasia posed problems with assessment of myometrial invasion. Patterns of myometrial invasion other than the conventional destructive pattern were sufficiently uncommon as to not impact on DMI measurement in large numbers of cases. Measuring the DMI is usually uncomplicated, but additional scrutiny should be paid to cases involving exophytic tumors, irregular endomyometrial junctions, adenomyosis, and extensive stromal smooth muscle metaplasia.

Molecular genetic changes in epithelial, stromal and mixed neoplasms of the endometrium

Endometrial carcinoma, endometrial stromal tumours and mixed malignant mesodermal tumours (MMMT) develop along distinctive molecular genetic pathways. Two distinctive types of endometrial carcinoma are distinguished, type I and type II, which develop along distinctive pathways and show different clinical behaviour and histological features. Type I carcinomas show endometrioid histology, are oestrogen-related and develop from atypical endometrial hyperplasia. The molecular tumorigenesis is comparable to colorectal carcinoma with a step-like progression and an accumulation of genetic alterations. Alterations of PTEN, K-Ras mutations and microsatellite instability are frequent and early events in type I carcinoma, whereas p53 mutations occur during progression to grade 3 carcinoma. Serous and clear cell carcinomas are considered type II carcinomas which are mostly unrelated to oestrogen. p53 mutations occur in almost all serous carcinomas and seem to occur early, leading to massive chromosomal instability and rapid tumour progression. Gene expression profiling has supported this dualistic model of endometrial carcinoma. There is evidence of molecular differences between serous and clear cell carcinomas as well as between endometrioid carcinomas with and without microsatellite instability. A dualistic model of tumorigenesis may be also suggested for endometrial stromal tumours. Endometrial stromal sarcomas (ESS; type I endometrial sarcoma) are oestrogen-related and seem to develop from endometrial stromal nodules (ESN). They are histologically and genetically distinct from undifferentiated endometrial sarcoma (UES) which seem to be mostly unrelated to oestrogen (type II endometrial sarcoma). ESS and ESN share the fusion gene JAZF1/JJAZ1 caused by a t(7;17)(p15;q21) translocation, whereas UES lacks a distinctive molecular alteration so far. In MMMT, which is considered a metaplastic carcinoma, p53 alteration occurs early, before clonal expansion and acquisition of genetic diversity during progression.

Recurrent endometrial stromal tumors with smooth-muscle differentiation and a protracted clinical course

BACKGROUND

A 24-year-old white female gravida 1, para 0010, presented with heavy vaginal bleeding and abdominal cramps of 2 weeks' duration. Medical history was remarkable for spontaneous abortion 5 years previously. She had no significant family history or other gynecological problems. Physical examination revealed tissue fragments and blood clots oozing from the cervical os, and her uterus was diffusely enlarged.

INVESTIGATIONS

Physical examination, ultrasound, uterine dilation and curettage, immunohistochemistry and human androgen receptor gene clonality analysis, uterine sonohistogram, MRI and exploratory laparotomy.

DIAGNOSIS

Intrauterine dissemination of endometrial stromal tumors with smooth-muscle differentiation.

MANAGEMENT

Partial wedge resection of the anterior uterine wall via abdominal myomectomy and total abdominal hysterectomy.

Gastrointestinal stromal tumor arising in the rectovaginal septum

We report herein a rare case of malignant gastrointestinal stromal tumor (GIST) originated from the rectal wall, which presented as a tumor on the rectovaginal septum. A 54-year-old Japanese woman, gravida 4, para 3, was admitted complaining of anuresis and severe constipation. She had a history of hysterectomy and right salpingo-oophorectomy for uterine leiomyoma 11 years previously. Pelvic examination revealed an 8.5 x 7.5 x 7.5 cm hard mass in the rectovaginal space. The inferior border of the tumor was 2 cm from the vaginal introitus and 2 cm from the anus. Computed tomography and magnetic resonance imaging showed a well-circumscribed soft-tissue mass filling the rectovaginal space. Urinary bladder and rectum were markedly compressed and displaced. Colon fiberscopy revealed invasion of the tumor into the rectal mucosa. An abdominoperineal resection of the rectum with posterior vaginal wall resection and pelvic lymphadenectomy was performed. The resected specimen showed a rectal submucosal tumor that was 8 x 8 x 7 cm in size. The tumor was diagnosed as a malignant GIST. Immunohistochemical analysis confirmed this diagnosis. The patient is now healthy without evidence of recurrence at 13 months after surgery. Gynecologists should be aware of rectal GIST arising in the rectovaginal space as a differential diagnosis of vaginal submucosal tumor.

Computed tomography gastrography with volume-rendering technique: correlation with double-contrast barium study and conventional gastroscopy

The volume-rendering technique uses computed tomography data to produce simulated images of conventional barium and endoscopic studies of the stomach. Various gastric lesions are detected on volume-rendered images, and submucosal tumors are easily differentiated from mucosal lesions by means of the overlying bridging fold. Lesions that are only manifested by a change of mucosal color (early gastric cancer type 2b) or a loss of mucosal detail (gastritis) are difficult to detect from volume-rendered images, however. In cases of gastric neoplasm and varix, both the extraluminal pathologies of the lesion and the relation between the intraluminal and extraluminal components can be evaluated simultaneously.

Sclerosing stromal tumor of the ovary in a premenarchal female

Sclerosing stromal tumor (SST) is a rare benign ovarian neoplasm of stromal origin with less than 100 cases reported in the literature. Unlike the other stromal tumors, thecomas and fibromas, which tend to occur in the fifth and sixth decades, sclerosing stromal tumors predominantly affect females in the second and third decades. Computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound findings have been described, but have not been reported previously in the pediatric literature. We present a case of SST of the ovary in a 10-year-old premenarchal female, the youngest patient to our knowledge reported in the literature, and describe the ultrasound and CT findings with pathologic correlation.