Uterine Tumours Resembling Ovarian Sex-Cord Tumors: A Case Report and Review of the Literature

Uterine tumors resembling ovarian sex-cord tumors (UTROSCT) are thought to develop from pluripotent uterine mesenchymal cells or endometrial stromal cells with secondary sex-cord differentiation. The patient was a 73-year-old postmenopausal woman who had abnormal vaginal bleeding, and she underwent a laparoscopic hysterectomy with bilateral salpingo-oophorectomy. The diagnosis was a case of UTROSCT. A scoping review of the UTROSCT case report present in the literature has been conducted, and 63 articles were found, of which 45 were considered for the 66 clinical cases examined. At the time of diagnosis, six metastatic localizations were found in 59 patients undergoing demolitive surgery (10.2%). Recurrences were diagnosed in 13/59 (22%) patients with multiple locations. A molecular study was performed in 18/66 cases (27.3%) and genetic alterations were found in 10/18 (55.6%) patients. UTROSCTs are considered rare uterine tumors, typically with a favorable prognosis, and are generally considered to have a good prognosis. But, from the review done, they may already manifest themselves at advanced stages, with the possibility of recurrences even at a distance. It would, therefore, be important to be able to define the most aggressive forms and, perhaps, molecular investigation with sequencing could help identify patients most at risk.


Introduction
Endometrial stromal tumors are not very frequent, and, occasionally, they might be difficult to diagnose.Uterine tumors resembling ovarian sex-cord tumors (UTROSCTs), which are uterine tumors resembling ovarian sex-cord tumors, were initially characterized by Morehead and Bowman in 1945 [1].
Then, based on clinical and histopathologic characteristics, Clement and Scully, in 1976, characterized 14 similar cases and further divided the neoplasms into two separate types [2].
Type I, endometrial stromal tumor with sex-cord-like elements (ESTCLEs) shows a predominant endometrial stromal pattern with areas of sex-cord-like structures that make up approximately 10-40% of the total tumor mass.The tumors are known as endometrial stromal tumors with sex-cord-like components and have a risk of metastasis and recurrence (ESTSCLEs) [3,4].
UTROSCTs, or type II uterine tumors resembling ovarian sex-cord tumors, are uncommon and often behave benignly [5].
The latest World Health Organization classification of female genital tumors, recognized in 2020, defined UTROSCT as a uterine tumor similar in shape to ovarian sex-cord tumors and further clarified that there is no discernible endometrial stromal component in this tumor tissue [6].
Our clinical case encouraged us to study the literature on this rare tumor to evaluate its behavior and prognosis.

Study Design
We conducted a scoping review, which allows a broad search while performing a systematic search, even though it does not require methodological appraisal or grading of the evidence [7].

Systematic Database Search
The electronic literature search was conducted from 1996 to November 2022 using PubMed/MEDLINE for English language abstracts.The search included the following medical subject headings (MeSH) or keywords: 'uterine tumor resembling ovarian sex-cord tumors', 'UTROSCT', and 'case report' studies published in English.

Eligibility Criteria
We included case reports or series, and other descriptive studies regarding the abovementioned research question.Literature reviews and guidelines published by scientific societies were also considered.

Exclusion Criteria
We excluded case reports and case series that did not report personal data, surgery, diagnosis, and immunohistochemistry.

Study Selection
The papers were retrieved by two authors independently; Mendeley was used to store the articles and delete duplicates.The two researchers screened all record titles and abstracts by using PUBMED; those with insufficient information were screened in full text.Disagreement between the reviewers was solved by discussion after reading the full text.The literature search was stopped in November 2022.

Case Report
The patient was a 73 year old postmenopausal woman with a history of four pregnancies (two full-term live births; two abortions in the first trimester of pregnancy) who had a history of irregular, abnormal vaginal bleeding for a few days.There was no family history of gynecological cancer.At physical examination, she was found to be in good general health, alert, and pale, with a flaccid abdomen and no signs of peritoneal irritation.At pelvic examination, the uterine volume appeared to be increased by two times the standard volume.The endometrial thickness was recorded at 18 mm by transvaginal ultrasonography and without evidence of uterine masses.Laboratory blood tests showed no significant abnormalities.In May 2022, the patient underwent operative hysteroscopy.Histopathology of the curettings showed endometrial hyperplasia without atypia.The patient, made aware of the risks of the surgery, asked to undergo laparoscopic hysterectomy with bilateral salpingo-oophorectomy.In addition, she received anti-inflammatory, rehydration, and anticoagulation therapy conventionally after surgery.After 28 h postsurgery, no intraoperative and postoperative complications occurred.After follow ups of 12 months and every six months, no recurrence occurred.

Pathological Features
Macroscopic examination showed multiple nodule lesions within the myometrium whose diameters ranged between 0.5 to 6 cm.All nodules except one showed macroscopic and microscopic features consistent with leiomyomas.On the other hand, a nodular lesion, measuring 2.5 cm in its greatest diameter, showed a yellowish cut surface and a solid consistency.Histologically, the neoplasia showed a diffuse pattern of growth with an alternating cord-like pattern and tubular and trabecular areas.(Figure 1A-C).Only focally large trabeculae were observed.Neoplastic cells were small in size and showed epithelioid morphology, with round, slightly irregular nuclei and scant eosinophilic cytoplasm (Figure 1D).Morphological features, such as necrosis, mitotic activity, lymphovascular invasion, and infiltrative margins, were not observed.

Pathological Features
Macroscopic examination showed multiple nodule lesions within the myometrium whose diameters ranged between 0.5 to 6 cm.All nodules except one showed macroscopic and microscopic features consistent with leiomyomas.On the other hand, a nodular lesion, measuring 2.5 cm in its greatest diameter, showed a yellowish cut surface and a solid consistency.Histologically, the neoplasia showed a diffuse pattern of growth with an alternating cord-like pattern and tubular and trabecular areas.(Figure 1A-C).Only focally large trabeculae were observed.Neoplastic cells were small in size and showed epithelioid morphology, with round, slightly irregular nuclei and scant eosinophilic cytoplasm (Figure 1D).Morphological features, such as necrosis, mitotic activity, lymphovascular invasion, and infiltrative margins, were not observed.
Through immunohistochemistry, neoplastic cells showed immunoreactivity for mesenchymal (vimentin, desmin) and epithelial (pan-cytokeratin AE1/AE3) markers.Estrogen and progesterone receptors were also positive.Moreover, the immunoreactivity for markers of sex-cord differentiation, including calretinin, CD99, CD56, and WT1 was also observed (Figure 2a-d).On the other hand, neoplastic cells were negative for smooth muscle actin, caldesmon, HMB45, Melan-A, and CD10.Based on the abovementioned morphological and immunohistochemical findings, the diagnosis of a uterine tumor resembling an ovarian sex-cord tumor (UTROSCT) was rendered.Through immunohistochemistry, neoplastic cells showed immunoreactivity for mesenchymal (vimentin, desmin) and epithelial (pan-cytokeratin AE1/AE3) markers.Estrogen and progesterone receptors were also positive.Moreover, the immunoreactivity for markers of sex-cord differentiation, including calretinin, CD99, CD56, and WT1 was also observed (Figure 2a-d).On the other hand, neoplastic cells were negative for smooth muscle actin, caldesmon, HMB45, Melan-A, and CD10.Based on the abovementioned morphological and immunohistochemical findings, the diagnosis of a uterine tumor resembling an ovarian sex-cord tumor (UTROSCT) was rendered.

Tissue-Sample Management
Overall, a series of four slides (5 microns) and a matching hematoxylin and eosin (H&E)-stained section was assessed for molecular analysis.The tumor tissue was manually microdissected by adopting a sterile blade and incubated overnight (O.N) at 56 • C with proteinase K.After this, nucleic acids were purified following the manufacturer instructions of the AllPrep DNA/RNA Kit (Qiagen, Hilden, Germany) [8].Briefly, genomic RNA (gRNA) was recovered on a proprietary filter column and eluted in 30 µL of DNAse and RNAse-free water (Thermo Fisher Scientifics, Waltham, MA, USA) in accordance with standardized procedures [8].Finally, gRNA was evaluated on the TapeStation 4200 microfluidic platform adopting a dedicated ScreenTape device (Agilent Technologies, Santa Clara, CA, USA).This system enables the calculation of the RNA concentration (pg/µL) and the RNA Integrity Number (RIN), a measurement of RNA fragmentation.The sample was stored at −20 • C until molecular analysis [9].

Tissue-Sample Management
Overall, a series of four slides (5 microns) and a matching hematoxylin and eosin (H&E)-stained section was assessed for molecular analysis.The tumor tissue was manually microdissected by adopting a sterile blade and incubated overnight (O.N) at 56 °C with proteinase K.After this, nucleic acids were purified following the manufacturer instructions of the AllPrep DNA/RNA Kit (Qiagen, Hilden, Germany) [8].Briefly, genomic RNA (gRNA) was recovered on a proprietary filter column and eluted in 30 μL of DNAse and RNAse-free water (Thermo Fisher Scientifics, Waltham, MA, USA) in accordance with standardized procedures [8].Finally, gRNA was evaluated on the TapeStation 4200 microfluidic platform adopting a dedicated ScreenTape device (Agilent Technologies, Santa Clara, CA, USA).This system enables the calculation of the RNA concentration (pg/μL) and the RNA Integrity Number (RIN), a measurement of RNA fragmentation.The sample was stored at −20 °C until molecular analysis [9].

NGS Analysis
Molecular analysis was carried out by adopting an Oncomine Precision Assay (OPA) panel on a fully automatized Genexus platform (Thermofisher Scientifics) following manufacturer procedures.Briefly, this platform allows for the automatic analysis of DNA/RNA samples (from library preparation to data interpretation) within 24 h.The OPA assay covers 50 cancer-related actionable genes, including the most common intergenic fusions in n = 16 actionable genes (ALK, ROS1, NTRK1-3, RET, FGFR1-3, NRG1, RSPO2-3, NUTM, ESR1, BRAF, and NRG1).Briefly, a sample sheet was generated on a dedicated server and assigned to a new run.The NGS platform was manually loaded with OPA primers, strip solutions, strip reagents, and supplies according to the manufacturer's instructions.A total of 10 ng was dispensed into a 96-well plate and put on the Genexus platform.Finally, a sequence analysis was carried out on the GX5TM chip that allows for simultaneous processing of n = 8 samples in a single line by adopting an OPA assay.Data

NGS Analysis
Molecular analysis was carried out by adopting an Oncomine Precision Assay (OPA) panel on a fully automatized Genexus platform (Thermofisher Scientifics) following manufacturer procedures.Briefly, this platform allows for the automatic analysis of DNA/RNA samples (from library preparation to data interpretation) within 24 h.The OPA assay covers 50 cancer-related actionable genes, including the most common intergenic fusions in n = 16 actionable genes (ALK, ROS1, NTRK1-3, RET, FGFR1-3, NRG1, RSPO2-3, NUTM, ESR1, BRAF, and NRG1).Briefly, a sample sheet was generated on a dedicated server and assigned to a new run.The NGS platform was manually loaded with OPA primers, strip solutions, strip reagents, and supplies according to the manufacturer's instructions.A total of 10 ng was dispensed into a 96-well plate and put on the Genexus platform.Finally, a sequence analysis was carried out on the GX5TM chip that allows for simultaneous processing of n = 8 samples in a single line by adopting an OPA assay.Data analysis was performed on the proprietary Genexus software, as recommended by the manufacturer's guidelines.Particularly, detected alterations were annotated by adopting Oncomine Knowledgebase Reporter Software (Oncomine Reporter 5.0) [10,11].A microfluidic analysis highlighted an RNA concentration of 858.0 pg/µL.Moreover, fragmentation analysis revealed a DIN of 2.8.From a technical point of view, a median number of 1,215,781.0total reads, 59,296.0mapped reads, and 95 mean read lengths were identified, respectively.No clinically relevant aberrant transcripts in cancer-related genes covered by the OPA assay were detected (Table 1).

Results
After the search that included the following medical subject headings (MeSH) or keywords 'uterine tumor resembling ovarian sex-cord tumors', 'UTROSCT', and 'case report' of studies published in English was completed, 63 articles were found, of which 45 were considered for a total of 66 clinical cases examined (Figure 3).The 66 patients examined were aged between 22 and 77 years old (average age 49.7 years).All patients underwent immunohistochemical investigation, which contributed to the differential diagnosis, validating the diagnosis of UTROSCT.For 4/66 (6%) patients, a follow up is not reported.The clinical cases that have been subjected to molecular investigation are 14/66 (21.2%).Thirty-seven out of 66 patients (56.1%) underwent subtotal/total hysterectomy with bilateral salpigo-oophorectomy (H-BSO), 10/66 (15.1%) underwent subtotal/total hysterectomy with bilateral salpingectomy (H-BS), and 12/66 (18.2%) underwent total hysterectomy with bilateral salpingo-oophorectomy and removal of pelvic and/or aortic lymph nodes.Finally, 7 patients underwent conservative surgery, of which 5/66 (7.6%) underwent hysteroscopy and 2/66 (3%) underwent myomectomy.At the time of diagnosis, six metastatic localizations were found in 59 patients undergoing demolitive surgery (10.2%).In particular, the following were highlighted: 2/12 (16.7%) localizations of lymph node metastases in patients subjected to the removal of pelvic and/or aortic lymph nodes, 2/49 (4.1%) localizations of ovarian metastases in patients subjected to HBSO/HBSO + lymphadenectomy, and 2/59 (3.4%) localizations of cervical metastases in patients undergoing total hysterectomy.Follow-up was performed in 59/66 patients.The mean duration of follow up was 45.9 months (1-384 months).Two out of seven patients undergoing conservative surgery had no follow up, and none of the patients treated with conservative surgery had a recurrence.Clinical cases treated with demolitive surgery were 59/66 (89.4%); of these, 5/59 (8.5%) did not perform a follow up.Recurrences were diagnosed in 13/59 (22%) patients with multiple locations.Local recurrences involved the ovary, vaginal vault, and pelvic peritoneum.Distant recurrences were localized in the peritoneum, liver, intestine, lung, and lymph nodes (Table 2).

Discussion
UTROSCT is a relatively rare disease.About 70 cases of UTROSCT have been described in the literature.The tumor typically affects postmenopausal women and women of childbearing age.The age of onset ranges from 20 to 86 years; the median age is 51 years.The most common symptom is abnormal uterine bleeding or pelvic pain, but it can occur asymptomatically [6,7].The tumor size ranges from 4 mm to 135 mm (on average 47.6 mm).This type of uterine tumor cannot be suspected using any of the instrumental tests we use (US, CT, or MRI), the precise diagnosis is established with tissue biopsy.According to histology, the tumors are made up of nests that resemble sex cords and epithelioid cells [4].
Studies have revealed that most UTROSCTs are positive for at least two sex-cordlabeled antibodies (CD99, calretinin, melan A, and inhibin), which are frequently joined by smooth muscle (SMA, desmin, and calponin), endometrial stromal (CD10), and other antibodies (vimentin, ER, and PR) with varying degrees of expression.This is true even though immunohistochemical markers did not reveal any specific targets [55].
Taking into consideration their rarity, only a few studies have explored the molecular alterations of UTROSCT.Mutations frequently occurring in ovarian sex-cord tumors, such as FOXL2 or DICER1, have not been observed in UTROSCT.Moreover, JAZF1-SUZ12 gene fusion, usually observed in endometrial stromal neoplasms has not been described in UTROSCT [3].
However, recent studies demonstrated that the majority of UTROSCTs carry recurrent NCOA2/3 gene fusions previously discovered in Mullerian adenosarcoma and undifferentiated uterine sarcoma.UTROSCT-harboring NCOA2/3 gene fusions have been shown to occur mainly in premenopausal patients and show unequivocal morphological and immunohistochemical evidence of sex-cord differentiation [56].
Moreover, rare UTROSCT cases showing fusions involving the GREB1 gene have also been reported.These latter cases have been shown to occur in older women and may show local recurrences [57].
Despite the fact that the majority of the UTROSCTs behave benignly, they are typically regarded as tumors with low malignant potential [6].The most frequent treatment pattern (65.1%) was total hysterectomy with bilateral adnexectomy, followed by total hysterectomy alone (18.6%), and mass resection alone (14%), respectively [58].
However, the uncertain behavior of the UTROSCTs emerged from this scoping review.In fact, we found that, in 10.2% of cases, metastases were found at the time of diagnosis.Furthermore, 22% of the cases in the literature with long-term follow up found the onset of recurrences with local localization (ovarian, vaginal, and pelvic) or metastasis (peritoneal, hepatic, lymph node, and pulmonary).This highlights the behavior of a pathology with an uncertain course, which deserves greater attention.To this end, on the basis of this scoping review, we underline the need to undertake an individualized treatment on the patient that can take into consideration the communication to the same of this pathology and, therefore, propose demolitive surgery in the first instance.If the patient wishes to perform conservative treatment, she must be informed of the risks of recurrence and the need to carry out close follow ups.To this must be added the importance of adding genetic investigation to the histological and molecular investigation, which can guide the choice of the clinician for the purpose of better management of the clinical case.

Conclusions
Until now, UTROSCTs, according to the WHO, are benign in most cases but should be considered to have low malignant potential because they may recur.Hysterectomy and mass resection alone are potential therapeutic options if risk indicators for recurrence, like genetic alteration, are not present.We, therefore, suggest considering this pathology to have uncertain behavior, carefully counseling the patient, and showing the risks of metastasis and recurrences, and, therefore, also personalizing treatment on the basis of molecular and genetic investigations.

Figure 1 .
Figure 1.Haematoxylin and eosin-stained sections illustrate the histopathological features of the present case.(A): On low power (4×) a hypercellular tumor with pushing margins is observed.(B,C): On medium power (10×), different patterns of growth were evident; neoplastic cells with diffuse patterns of growth (B) or arranged in tubules (C).(D): on high power (40×), neoplastic cells showed epithelioid morphology, with round, slightly irregular nuclei, and scant eosinophilic cytoplasm without evidence of nuclear atypia or mitotic figure.

Figure 1 .
Figure 1.Haematoxylin and eosin-stained sections illustrate the histopathological features of the present case.(A): On low power (4×) a hypercellular tumor with pushing margins is observed.(B,C): On medium power (10×), different patterns of growth were evident; neoplastic cells with diffuse patterns of growth (B) or arranged in tubules (C).(D): on high power (40×), neoplastic cells showed epithelioid morphology, with round, slightly irregular nuclei, and scant eosinophilic cytoplasm without evidence of nuclear atypia or mitotic figure.

Figure 3 .Figure 3 .
Figure 3. Flow diagram for scoping reviews, which included searches of PUBMED.