Primary omental smooth muscle tumor in an adult male: a diagnostic dilemma for leiomyoma: a case report.

BACKGROUND: The greater omentum comprises peritoneal, adipose, vascular, and lymphoid tissues. Most omental malignancies are metastatic tumors, and the incidence of primary tumors is rare. We report on a prior omental smooth muscle tumor case in an adult male patient. CASE PRESENTATION: A 54-year-old Japanese male patient with no relevant medical history was diagnosed with an abdominal mass during a routine medical checkup. Subsequent contrast-enhanced computed tomography revealed a mass of approximately 3 cm in size in the greater omentum, and a laparotomy was performed. A 27 × 25 × 20 mm raised lesion was found in the omentum. Microscopically, spindle cells were observed and arranged in whorls and fascicles. Individual tumor cells had short spindle-shaped nuclei with slightly increased chromatin and were characterized by a slightly eosinophilic, spindle-shaped cytoplasm. The mitotic count was less than 1 per 50 high-power fields. The tumor cells showed positive immunoreactivity for α smooth muscle actin, HHF35, and desmin on immunohistochemical examination. The Ki-67 labeling index using the average method was 1.76% (261/14806). No immunoreactivity was observed for any of the other tested markers. We considered leiomyoma owing to a lack of malignant findings. However, primary omental leiomyoma has rarely been reported, and it can be difficult to completely rule out the malignant potential of smooth muscle tumors in soft tissues. Our patient was decisively diagnosed with a primary omental smooth muscle tumor considering leiomyoma. Consequently, the patient did not undergo additional adjuvant therapy and was followed up. The patient was satisfied with treatment and showed neither recurrence nor metastasis at the 13-month postoperative follow-up. DISCUSSION AND CONCLUSION: We encountered a primary smooth muscle tumor of the greater omentum with no histological findings suggestive of malignancy in an adult male patient. However, omental smooth muscle tumors are extremely difficult to define as benign, requiring careful diagnosis. Further case reports with long-term follow-up and case series are required to determine whether a true omental benign smooth muscle tumor (leiomyoma) exists. In addition, proper interpretation of the Ki-67 labeling index should be established. This case study is a foundation for future research.

FOXO3a deregulation in uterine smooth muscle tumors.

OBJECTIVE: The present study aimed to investigate FOXO3a deregulation in Uterine Smooth Muscle Tumors (USMT) and its potential association with cancer development and prognosis. METHODS: The authors analyzed gene and protein expression profiles of FOXO3a in 56 uterine Leiomyosarcomas (LMS), 119 leiomyomas (comprising conventional and unusual leiomyomas), and 20 Myometrium (MM) samples. The authors used techniques such as Immunohistochemistry (IHC), FISH/CISH, and qRT-PCR for the present analyses. Additionally, the authors conducted an in-silico analysis to understand the interaction network involving FOXO3a and its correlated genes. RESULTS: This investigation revealed distinct expression patterns of the FOXO3a gene and protein, including both normal and phosphorylated forms. Expression levels were notably elevated in LMS, and Unusual Leiomyomas (ULM) compared to conventional Leiomyomas (LM) and Myometrium (MM) samples. This upregulation was significantly associated with metastasis and Overall Survival (OS) in LMS patients. Intriguingly, FOXO3a deregulation did not seem to be influenced by EGF/HER-2 signaling, as there were minimal levels of EGF and VEGF expression detected, and HER-2 and EGFR were negative in the analyzed samples. In the examination of miRNAs, the authors observed upregulation of miR-96-5p and miR-155-5p, which are known negative regulators of FOXO3a, in LMS samples. Conversely, the tumor suppressor miR-let7c-5p was downregulated. CONCLUSIONS: In summary, the outcomes of the present study suggest that the imbalance in FOXO3a within Uterine Smooth Muscle Tumors might arise from both protein phosphorylation and miRNA activity. FOXO3a could emerge as a promising therapeutic target for individuals with Unusual Leiomyomas and Leiomyosarcomas (ULM and LMS), offering novel directions for treatment strategies.

Tumor nasal de músculo liso de comportamiento maligno incierto: informe de un caso / Nasal smooth muscle tumor of uncertain malignant potential: A case report

Los tumores de músculo liso que no pueden ser clasificados según su histología como leiomiomas o leiomiosarcomas se denominan tumores de músculo liso de comportamiento maligno incierto. La localización nasal de estos tumores es muy infrecuente y la extensión adecuada de la cirugía para tratar estas neoplasias no está bien definida. Se describe el caso clínico de una adolescente de 16 años, que consultó por padecer un tumor de aspecto vascular en la cavidad nasal derecha y que fue tratada con éxito mediante cirugía intranasal. El diagnóstico histológico fue tumor de músculo liso de comportamiento maligno incierto. Por la rareza de estas neoplasias, su infrecuente localización nasal y la falta de evidencia que soporte cuál debe ser la extensión de la cirugía, es relevante la descripción y discusión del caso clínico.

Smooth muscle tumors that cannot be histologically classified as leiomyomas or leiomyosarcomas are defined as smooth muscle tumors of uncertain malignant potential. The location of these tumors in the nose is very rare, and the appropriate surgical extent to manage these neoplasms has not been adequately defined. Here we describe the case of a 16-year-old female adolescent who consulted due to a vascular-like tumor in the right nasal cavity who was successfully treated with intranasal surgery. The histological diagnosis was smooth muscle tumor of uncertain malignant potential. Given that these neoplasms are rare, the uncommon location in the nose, and the lack of evidence indicating the extent of surgery, it is relevant to describe and discuss this clinical case.

Pulmonary Epstein-Barr virus-associated smooth muscle tumor after kidney transplantation: two case reports with review of differential diagnosis.

Pulmonary nodules are a common complication in solid organ transplant recipients, and may have various underlying causes, with Epstein-Barr virus-associated smooth muscle tumor (EBV-SMT) being one of them. Given the rarity of this entity, we describe the diagnosis and therapeutic interventions for post-transplant EBV-SMT in two individuals. Both cases involved female patients who were diagnosed with multiple pulmonary nodules 60 months and 116 months, respectively, after receiving living-related kidney transplantation. Pathological examination revealed a spindle cell tumor, with immunophenotype and EBV in situ hybridization supporting the diagnosis of EBV-SMT. After diagnosis, these two patients underwent intervention by decreasing their intake of immunosuppressants. As of the latest follow-up, the patients' lesion size remained stable, and their overall condition was favorable. We also reviewed literature about the morphological and molecular pathological features of EBV-SMT and highlighted the diagnosis and differential diagnosis of pulmonary spindle cell lesions especially in the setting of immunosuppression.

Inflammatory Rhabdomyoblastic Tumor: From a Nebulous Smooth Muscle Neoplasm to a Novel Skeletal Muscle Tumor Subtype.

Inflammatory rhabdomyoblastic tumor is a recently introduced name for neoplasms currently included in the World Health Organization classification of soft tissue tumors under the rubric inflammatory leiomyosarcoma. Inflammatory rhabdomyoblastic tumor is an excellent example of how surgical pathologists working in conjunction with tumor biologists can greatly improve tumor classification to the benefit of patients. Over the last 28 years, understanding of this entity has undergone a fascinating evolution. This review serves as a summary of the latest findings in inflammatory rhabdomyoblastic tumor research and a diagnostic manual for the practicing surgical pathologist.

Smooth muscle tumours of the uterus: MR imaging malignant predictive features-a 12-year analysis in a referral hospital in Portugal.

PURPOSE: To evaluate the magnetic resonance imaging (MRI) features that may help distinguish leiomyosarcomas from atypical leiomyomas (those presenting hyperintensity on T2-W images equal or superior to 50% compared to the myometrium). MATERIALS AND METHODS: The authors conducted a retrospective single-centre study that included a total of 57 women diagnosed with smooth muscle tumour of the uterus, who were evaluated with pelvic MRI, between January 2009 and March 2020. All cases had a histologically proven diagnosis (31 Atypical Leiomyomas-ALM; 26 Leiomyosarcomas-LMS). The MRI features evaluated in this study included: age at presentation, dimension, contours, intra-tumoral haemorrhagic areas, T2-WI heterogeneity, T2-WI dark areas, flow voids, cyst areas, necrosis, restriction on diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC) values, signal intensity and heterogeneity after contrast administration in T1-WI, presence and location of unenhanced areas. The association between the MRI characteristics and the histological subtype was evaluated using Chi-Square and ANOVA tests. RESULTS: The MRI parameters that showed a statistically significance correlation with malignant histology and thus most strongly associated with LMS were found to be: irregular contours (p < 0.001), intra-tumoral haemorrhagic areas (p = 0.028), T2-WI dark areas (p = 0.016), high signal intensity after contrast administration (p = 0.005), necrosis (p = 0.001), central location for unenhanced areas (p = 0.026), and ADC value lower than 0.88 × 10-3 mm2/s (p = 0.002). CONCLUSION: With our work, we demonstrate the presence of seven MRI features that are statistically significant in differentiating between LMS and ALM.

Epstein-Barr Virus-Positive Leiomyosarcoma in Immunocompetent Patients.

OBJECTIVE: Epstein-Barr Virus-Associated Smooth Muscle Tumor (EBV-SMT) is a rare tumor with a higher rate of occurrence in unusual locations in the setting of immunodeficiency. In this study, we evaluated a cohort of ordinary leiomyosarcomas (LMS) for the presence of EBV and described the clinicopathological features deviating from routinely diagnosed cases of EBV-SMT. MATERIAL AND METHOD: The sections of tissue microarrays including 93 classical LMS occurring in various locations were hybridized with EBER and stained for LMP1 antibody using the Leica Bond Autostainer. EBV real-time PCR assay was performed in 2 EBER-positive cases. RESULTS: Among the 93 LMS cases, 2 non-uterine cases (2.2%) were positive for EBER and negative for LMP1, and were referred to as `EBV-positive LMS`. Both were females in their 6th decade without immunosuppression. EBV real-time PCR assay revealed the presence of EBV in one of the cases. Tumors were located in the pancreas and chest wall. Morphologically, tumors were rather myxoid, multinodular, and composed of long fascicles of spindle cells with intermediate- to high-grade features. High mitotic activity and focal necrosis were present, whereas no accompanying lymphocytes were detected. One of the patients developed metastatic disease after 3 years. CONCLUSION: EBV-positive LMS occurring in immunocompetent patients has features distinct from classical EBV-SMT seen in immunosuppressed patients.

Malignant female genital tract smooth muscle tumors with adipocytic differentiation: A morphologic, immunohistochemical, MDM2 fluorescence in situ hybridization and molecular genetic study of 6 lipoleiomyosarcomas.

Leiomyosarcoma with adipocytic differentiation or lipoleiomyosarcoma is an uncommon sarcoma of the female genital tract with only a few individual reports in the literature. We therefore performed a morphologic, immunohistochemical, MDM2 gene amplification and RNA and DNA sequencing analysis of a series of gynecologic lipoleiomyosarcoma to better define the clinicopathologic spectrum. Six tumors from 6 patients were identified and classified as spindled lipoleiomyosarcoma (n = 2), mixed spindled and myxoid lipoleiomyosarcoma (n = 1), epithelioid lipoleiomyosarcoma with focal myxoid features (n = 1) and mixed spindled and epithelioid lipoleiomyosarcoma (n = 2). Patient age ranged from 41 to 64 years (mean: 49; median: 50). Primary location included uterine corpus (3), uterine corpus/cervix (2) and broad ligament (1). Tumor size ranged from 4.5 to 22 cm (mean: 11.2; median: 9.8). Four patients had metastasis at presentation or subsequently developed recurrent or distant disease. Patient status was known for 5: 2 dead of disease, 2 alive with disease and 1 alive without evidence of disease. Immunohistochemical expression of smooth muscle markers, ER, PR and WT-1 showed patterns similar to non-adipocytic gynecologic leiomyosarcomas. MDM2 amplification fluorescence in situ hybridization performed on 2 tumors was negative in 1 and equivocal in 1. Sequencing studies performed on 3 tumors found TP53 mutations in 3, with 1 tumor also having an ATRX alteration. No gene fusions were identified. Although lipoleiomyosarcomas have a diverse morphologic spectrum, our findings suggest the smooth muscle component shares morphologic and immunohistochemical features with female genital tract non-adipocytic leiomyosarcomas. Lipoleiomyosarcomas also have genetic alterations associated with non-adipocytic gynecologic leiomyosarcomas.

Myxoid epithelioid smooth muscle tumor of the vulva: A distinct entity with MEF2D::NCOA2 gene fusion.

Smooth muscle tumors are the most common mesenchymal tumors of the female genital tract, including the vulva. Since vulvar smooth muscle tumors are rare, our understanding of them compared to their uterine counterparts continues to evolve. Herein, we present two cases of morphologically distinct myxoid epithelioid smooth muscle tumors of the vulva with novel MEF2D::NCOA2 gene fusion. The tumors involved 24 and 37-year-old women. Both tumors presented as palpable vulvar masses that were circumscribed, measuring 2.8 and 5.1 cm in greatest dimension. Histologically, they were composed of epithelioid to spindle-shaped cells with minimal cytologic atypia and prominent myxoid matrix. Rare mitotic figures were present (1-3 mitotic figures per 10 high-power field (HPF)), and no areas of tumor necrosis were identified. By immunohistochemistry, the neoplastic cells strongly expressed smooth muscle actin, calponin, and desmin, confirming smooth muscle origin. Next-generation sequencing identified identical MEF2D::NCOA2 gene fusions. These two cases demonstrate that at least a subset of myxoid epithelioid smooth muscle tumors of the vulva represent a distinct entity characterized by a novel MEF2D::NCOA2 gene fusion. Importantly, recognition of the distinct morphologic and genetic features of these tumors is key to understanding the biological potential of these rare tumors.

Nasal smooth muscle tumor of uncertain malignant potential: A case report. / Tumor nasal de músculo liso de comportamiento maligno incierto: informe de un caso.

Smooth muscle tumors that cannot be histologically classified as leiomyomas or leiomyosarcomas are defined as smooth muscle tumors of uncertain malignant potential. The location of these tumors in the nose is very rare, and the appropriate surgical extent to manage these neoplasms has not been adequately defined. Here we describe the case of a 16-year-old female adolescent who consulted due to a vascular-like tumor in the right nasal cavity who was successfully treated with intranasal surgery. The histological diagnosis was smooth muscle tumor of uncertain malignant potential. Given that these neoplasms are rare, the uncommon location in the nose, and the lack of evidence indicating the extent of surgery, it is relevant to describe and discuss this clinical case.

Los tumores de músculo liso que no pueden ser clasificados según su histología como leiomiomas o leiomiosarcomas se denominan tumores de músculo liso de comportamiento maligno incierto. La localización nasal de estos tumores es muy infrecuente y la extensión adecuada de la cirugía para tratar estas neoplasias no está bien definida. Se describe el caso clínico de una adolescente de 16 años, que consultó por padecer un tumor de aspecto vascular en la cavidad nasal derecha y que fue tratada con éxito mediante cirugía intranasal. El diagnóstico histológico fue tumor de músculo liso de comportamiento maligno incierto. Por la rareza de estas neoplasias, su infrecuente localización nasal y la falta de evidencia que soporte cuál debe ser la extensión de la cirugía, es relevante la descripción y discusión del caso clínico.

POTENTIAL LIFE PROGNOSTIC MARKER FOR MESENCHYMAL TUMOR RESEMBLING UTERINE LEIOMYOSARCOMA.

Benign uterine leiomyoma (U.LMA) and malignant uterine leiomyosarcoma (U.LMS), both uterine mesenchymal tumors, are distinguished by the number of cells exhibiting mitotic activity. However, uterine mesenchymal tumors contain tumor cells with various cell morphologies; therefore, making a diagnosis, including differentiating between benign and malignant tumors, is difficult. For example, cotyledonoid dissecting leiomyoma (CDL) or uterine smooth muscle tumors of uncertain malignant potential (STUMPs) are a group of uterine mesenchymal tumors for which a differential diagnosis is challenging. To date, a standardized classification system for uterine mesenchymal tumors has not yet been established. Furthermore, definitive preoperative imaging techniques or hematological examinations for the potential inclusion of CDL or STUMP in the differential diagnosis have not been defined. Several clinical studies have reported that there is no correlation between biomarker expression and mitotic rate or tumor recurrence. The immunohistochemical biomarkers reported so far cannot effectively help determine the malignant potential of CDL or STUMPs in patients who wish to become pregnant in the future. The establishment of gene expression profiles or detection of pathogenic variants by using next-generation molecular techniques can facilitate disease prediction, diagnosis, treatment, and prognosis. We examined the oncological properties of STUMP in adults using molecular pathological techniques on tissue excised from patients with uterine mesenchymal tumor. In a clinical study conducted by our medical team, the results of gene expression profiling indicated factors that may be associated with malignancy of uterine mesenchymal tumors. We herein describe the problems in diagnosing uterine mesenchymal tumors along with the results of the latest clinical studies. It is expected that the establishment of a diagnostic method targeting the characteristics of mesenchymal tumor cells will lead to the treatment of malignant tumors with a low risk of recurrence and metastasis.

Long-term effect of letrozole on metastatic uterine smooth muscle tumors of uncertain malignant potential: A case report.

A 48-year-old woman underwent total abdominal hysterectomy and right salpingo-oophorectomy and was initially diagnosed with a uterine leiomyoma and right ovarian cystadenoma. After 4 years, multiple pulmonary metastases were identified, and treatment with gonadotropin-releasing hormone agonists was started, but stopped later due to disease progression. The patient developed dyspnea and underwent right upper lobectomy. The histopathological findings were consistent with those of pulmonary metastases secondary to a uterine smooth muscle tumor of uncertain malignant potential. Slow disease progression after a poor response to adriamycin and hormone receptor positivity led to the start of letrozole. Letrozole induced spontaneous regression of the pulmonary metastases, and about 2 years into the treatment, sustained response was achieved with minimal side effects. This may be the first case supporting the long-term efficacy and safety of letrozole in the management of adriamycin-resistant lung metastases of uterine smooth muscle tumors of uncertain malignant potential.

Quantitative MR texture analysis for the differentiation of uterine smooth muscle tumors with high signal intensity on T2-weighted imaging.

The purpose of this study was to distinguish leiomyosarcomas/smooth muscle tumors of uncertain malignant potential (STUMP) from leiomyomas with high signal intensity (SI) on T2-weighted imaging (T2WI) using quantitative MR texture analysis combined with patient characteristics and visual assessment. Thirty-one leiomyomas, 2 STUMPs, and 6 leiomyosarcomas showing high SI on T2WI were included. First, we searched for differences in patient characteristics and visual assessment between leiomyomas and leiomyosarcomas/STUMPs. We also compared the MR texture on T2WI and the apparent diffusion coefficient (ADC) to identify differences between leiomyomas and leiomyosarcomas/STUMPs. In the univariate analysis, significant differences between leiomyomas and leiomyosarcomas/STUMPs were observed in age, menopausal status, margin, hemorrhage, long diameter, T2-variance, T2-volume, ADC-variance, ADC-entropy, ADC-uniformity, ADC-90th and 95th percentile values, and ADC-volume (P < .05, respectively). There were significantly more postmenopausal patients with leiomyosarcomas/STUMPs than with leiomyomas, and leiomyosarcomas/STUMPs had more irregular margins, more frequent presence of hemorrhage and exhibited larger tumor diameters, T2-volume, T2-variance, ADC-volume, ADC-variance, ADC-entropy, and higher ADC-90th and 95th percentile values but lower ADC-uniformity. Multivariate analyses revealed that the independent differentiators were menopausal status, hemorrhage and ADC-entropy (P < .05, respectively). The area under the curve obtained by combining the 3 items was 0.980. The best cutoff value for ADC-entropy was 9.625 (sensitivity: 100%, specificity: 58%). The combination of menopausal status, hemorrhage, and ADC-entropy can help accurately distinguish leiomyosarcomas/STUMPs from leiomyomas with high SI on T2WI; however, external validation in a larger population is required because of the small sample size of our study.

Smooth Muscle Tumors of the Uterus at MRI: Focus on Leiomyomas and FIGO Classification.

Leiomyomas are smooth muscle tumors of the uterus and are the most common uterine neoplasm. Although leiomyomas are usually asymptomatic, they can manifest with symptoms such as pain or uterine bleeding. Leiomyomas are classified on the basis of their anatomic location and morphology. Localization of leiomyomas relative to the endometrium, myometrium, and uterine serosa with use of the International Federation of Gynecology and Obstetrics (FIGO) classification system is helpful for guiding management in symptomatic patients. The FIGO system is a practical and universally accepted approach for classifying leiomyomas to guide radiologists and clinicians in deciding management. The MRI appearance of conventional leiomyomas is related to their tissue contents of smooth muscle and fibrous tissue and is well established. The MRI features of some leiomyoma subtypes and forms of degeneration also have been described. Other smooth muscle tumors of the uterus recognized in the 2020 World Health Organization classification system include intravenous leiomyomatosis, smooth muscle tumors of uncertain malignant potential, and metastasizing leiomyoma. At the far end of the spectrum are leiomyosarcomas, which are frankly malignant and therefore must be managed accordingly. Although MRI features that suggest a diagnosis of leiomyosarcoma have been proposed, these features overlap with those of some leiomyoma subtypes and degeneration. © RSNA, 2023 See the invited commentary by Fennessy and Gargiulo in this issue. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. Quiz questions for this article are available through the Online Learning Center.

EBV-Associated Smooth Muscle Tumor in the Malar Area of an HIV-Positive Patient: A Case Report.

BACKGROUND: EBV-associated smooth muscle tumors (EBV-SMTs) are rare and typically develop in individuals with a compromised immune system, particularly those who have acquired immunodeficiency syndrome (AIDS) or who have undergone organ transplants. METHODS: We document a case of EBV-SMT in an HIV-positive 25-year-old man. The lesion was incised and assessed histologically and a panel of immune markers were performed. EBV association was demonstrated by in situ hybridization for EBV-encoded RNA (EBER-ISH). RESULTS: Microscopically, the tumor composed of mildly pleomorphic, ovoid to spindled cells with numerous slit-like vascular channels. The tumor cells exhibited diffuse and strong immunoreactivity for smooth muscle actin (SMA) and focal positivity for h-caldesmon. EBER-ISH of the tumor cells revealed strong positive nuclear signals. CONCLUSION: The histopathological features of EBV-SMT do not conform to either benign or malignant SMTs and it has a peculiar predilection to develop at sites unusual for leiomyoma or leiomyosarcoma. The key diagnostic features of EBV-SMT include history of immunosuppression, histologic evidence of primitive and mildly pleomorphic cells maintaining blunt nuclear features in most areas, and positivity for EBER-ISH.

Clinicopathologic and Molecular Characteristics of Epstein-Barr Virus-Associated Smooth Muscle Tumor Compared With Those of Leiomyoma and Leiomyosarcoma.

Epstein-Barr virus (EBV)-associated smooth muscle tumors (EBV-SMTs) are rare smooth muscle neoplasms exclusively associated with immunosuppression, such as in patients with HIV/AIDS, posttransplant, and congenital immunodeficiency. However, the genomic landscape of EBV-SMTs is poorly understood. Leiomyosarcomas harbor genomic instability and multiple recurrent DNA copy number alterations, whereas leiomyomas lack such changes. Thus, this study aimed to fill this knowledge gap by characterizing copy number alterations in EBV-SMTs and correlating this information with clinicopathologic characteristics. Our study investigated and compared the pathologic characteristics and copy number profiles of 9 EBV-SMTs (from 7 post-transplant and AIDS patients), 6 leiomyomas, and 7 leiomyosarcomas, using chromosomal microarray platforms. Our results showed a lower copy number alteration burden in EBV-SMTs and leiomyoma than in leiomyosarcoma. This contrast in the molecular profile between EBV-SMTs and leiomyosarcoma is concordant with the different clinical behaviors and pathologic characteristics exhibited by these tumors. Despite having an overall copy number alteration profile closer to leiomyoma, recurrent copy number gain of oncogenes, such as RUNX1, CCND2, and ETS2, was found in EBV-SMTs. Epigenetic alterations may play an important role in tumorigenesis as recurrent copy number gains were found in histone deacetylases. A gene enrichment analysis also demonstrated enrichment of genes involved in the host response to viral infection, suggesting that the tumor immune microenvironment may play an important role in EBV-SMT tumorigenesis.

Uterine smooth muscle tumors with uncertain malignant potential: analysis following fertility-saving procedures.

OBJECTIVE: The aim of this study was to analyze the clinical and reproductive outcomes of patients treated with myomectomy who were histologically diagnosed with uterine smooth muscle tumor of uncertain malignant potential (STUMP). METHODS: Patients who were diagnosed with STUMP and underwent a myomectomy at our institution between October 2003 and October 2019 were identified. Variables of interest obtained from the institution's database included patient age, relevant medical history, pre-operative appearance of the tumor on ultrasound, parameters of the surgical procedure, histopathological analysis of the tumor, post-operative clinical course, and course of follow-up, including reinterventions and fertility outcomes. RESULTS: There were a total of 46 patients that fulfilled the criteria of STUMP. The median patient age was 36 years (range, 18-48 years) and the mean follow-up was 47.6 months (range, 7-149 months). Thirty-four patients underwent primary laparoscopic procedures. Power morcellation was used for specimen extraction in 19 cases (55.9% of laparoscopic procedures). Endobag retrieval was used in nine patients and six procedures were converted to an open approach due to the suspicious peri-operative appearance of the tumor. Five patients underwent elective laparotomy due to the size and/or number of tumors; three patients had vaginal myomectomy; two patients had the tumor removed during planned cesarean section; and two underwent hysteroscopic resection.There were 13 reinterventions (five myomectomies and eight hysterectomies) with benign histology in 11 cases and STUMP histology in two cases (4.3% of all patients). We did not observe any recurrence as leiomyosarcoma or other uterine malignancy. We did not observe any deaths related to the diagnosis. Twenty-two pregnancies were recorded among 17 women, which resulted in 18 uncomplicated deliveries (17 by cesarean section and one vaginal), two missed abortions, and two pregnancy terminations. CONCLUSIONS: Our study found that uterus-saving procedures and fertility-preservation strategies in women with STUMP are feasible, safe, and seem to be associated with a low risk of malignant recurrence, even while maintaining the mini-invasive laparoscopic approach.