Ultrasound and clinical characteristics of uterine smooth muscle tumors of uncertain malignant potential (STUMPs)

Large uterine smooth muscle tumors of unknown malignant potential mimicking a mucinous ovarian tumor: A challenging preoperative diagnosis

We described a challenging case of a uterine smooth muscle tumors of unknown malignant potential (STUMP) presenting as an ovarian mucinous tumor. This differential diagnosis should be considered when preoperatively evaluating cystic multilocular lesions.

Clinical and ultrasound features of uterine perivascular epithelioid cell tumors: case series and literature review

OBJECTIVE

To describe the clinical and ultrasonographic features of uterine perivascular epithelioid cell tumor (PEComa) using standardized terminology.

METHODS

This was a retrospective analysis of patients with uterine PEComa diagnosed and confirmed by pathology and immunohistochemistry at West China Second University Hospital, Sichuan University, Sichuan, China, between January 2010 and September 2023. The Morphological Uterus Sonographic Assessment (MUSA) consensus and the International Endometrial Tumor Analysis (IETA) consensus were utilized for the standardized description of the sonographic characteristics of uterine PEComa. We summarized the clinical and ultrasound features of uterine PEComa in cases from our center and those found in a review of the literature conducted using PubMed from 1 January 2013 to 30 September 2023 (inclusive).

RESULTS

Five patients, aged 33-57 (median, 52) years, with a total of six uterine PEComa lesions were included in our cohort. All cases had complete ultrasonographic and pathological images. None of the patients had a history of tuberous sclerosis complex. Two patients had malignant PEComa (one patient had two lesions) and three had benign PEComa, originating from the cervix, myometrium or uterine cavity. Patients presented with symptoms including increased vaginal discharge, vaginal bleeding and pelvic or abdominal pain. The three patients with benign PEComa underwent total hysterectomy and bilateral adnexectomy, tumor excision and conservative management, respectively, while both malignant cases underwent total hysterectomy and bilateral adnexectomy followed by chemotherapy. Regular follow-up (from 6 to 24 months) revealed recurrence in one case. Two lesions were misdiagnosed as uterine fibroids, two as cervical cancer, one as metastatic cervical cancer (with myometrial invasion) and one was indeterminate. Ultrasound examination showed that most lesions displayed regular round or ovoid shape (66.7%), uniform echoes (66.7%) and hypoechogenicity (66.7%), with one (16.7%) malignant PEComa showing cystic areas and one (16.7%) benign PEComa showing punctate calcifications. All lesions lacked shadowing and the majority showed moderate to abundant vascularity (color score of 3-4, 83.3%). The color score was 2-4 in the periphery in 100% of cases and internally in 83.3% of cases. The three benign PEComas showed similar characteristics in vascular distribution, with scattered internal vessels and peripheral vessels exhibiting a circular pattern. The literature search identified 11 articles describing the ultrasonographic appearance of 18 cases of uterine PEComa, with similar characteristics to those in our cohort.

CONCLUSIONS

The sonographic features of uterine PEComa include a uniform or non-uniform hypoechogenic mass, typically round or ovoid with regular margins, occasionally containing cystic areas or calcifications, lacking shadowing and often showing moderate to abundant vascularity. Although the preoperative ultrasound diagnosis of uterine PEComa remains challenging, particularly given the non-specific nature of the sonographic characteristics described here, dispersed intratumoral vessels and a peripheral circular vascular distribution may serve as diagnostic clues for uterine PEComa, but more cases are needed for confirmation. © 2024 International Society of Ultrasound in Obstetrics and Gynecology.

Smooth muscle tumors of uncertain malignant potential or atypical leiomyomas: A long-term evaluation of surgical outcomes and clinicopathological features

OBJECTIVE

The Primary Objective of this study was to analyse reproductive outcomes in patients with STUMP (Smooth Muscle Tumour of Uncertain Potential) or ALM (Atypical Leiomyoma) who underwent fertility-preserving surgeries. Secondary Objectives were to analyse long-term prognosis for these patients and to study the basic demographic and pathological characteristics of patients with STUMP or ALM.

STUDY DESIGN

This retrospective study was conducted at Amrita Institute of Medical Sciences. Cases of STUMP and ALM were retrieved from the hospital medical database between June 2014 and December 2022. Demographic parameters, clinical presentations, pathological features and clinical outcomes were analysed. Categorical variables were expressed in numbers and percentages. Normal distribution data were presented as mean while non-normal distribution was expressed as median and range.

RESULTS

Thirty-eight patients were included in the study with a diagnosis of STUMP or ALM in postoperative histology. Seven patients (18.4%) were nulliparous. Myomectomy was performed in 9 (23.6%), while hysterectomy was done in 29 patients (76.3%). Fertility-preserving surgeries were performed on six patients (15.7%). Of these six patients, 4(66.6%) conceived spontaneously and had successful pregnancies. Recurrences were found in 3 patients (7.8%) out of which one had undergone fertility-sparing surgery. All the patients with recurrences had previous history of myomectomies. Morcellation was reportedly done in 2 of these three patients.

CONCLUSION

Good reproductive outcomes have been demonstrated in patients diagnosed with STUMP or ALM and desiring fertility. However, these patients should be kept under follow-up care as they are prone for recurrences. Patients who have undergone morcellation mayhave an increased chance of recurrence.

Imaging characteristics of uterine smooth muscle tumors of uncertain malignant potential: a case report and literature review

Uterine smooth muscle tumors of uncertain malignant potential (STUMPs) are rare tumors of the uterine myometrium that are often misdiagnosed, owing to limited knowledge of their characteristics on ultrasonography (US) and magnetic resonance imaging (MRI). We report a woman in her mid-30s who was hospitalized because of a pelvic tumor. A 6-cm mass was found in her lower left abdomen. US and MRI revealed a well-demarcated mass in the left adnexal area, with both cystic and solid elements, visible blood flow within the septa, a strong signal across >50% of the volume on T2-weighted imaging (T2WI), and a strong signal on diffusion-weighted imaging (DWI). After hysterectomy and bilateral salpingectomy, immunohistochemical examination confirmed STUMP. A review of the literature revealed characteristic imaging features of STUMP. Ultrasonography reveals STUMP as a solitary, well-circumscribed lesion with isoechoic or mixed echogenicity, the absence of posterior shadowing, and variations in blood flow. STUMP is characterized by strong signal intensity on T2WI, small areas of strong signal on T1WI, and non-enhancing cystic areas on contrast-enhanced MRI scans. Early diagnosis is crucial for the management and treatment of STUMP, and here we have summarized the imaging features of the lesion, thereby providing a valuable diagnostic reference.

Ultrasound Appearance of Intravascular Uterine Smooth Muscle Tumor of Uncertain Malignant Potential (STUMP): A Case Report

A 43-year-old patient with a history of uterine fibromatosis was referred to our hospital for menometrorrhagia and pelvic pain. At the pelvic ultrasound, a highly-vascularized myometrial lesion in volumetric increase was described. An elongated, solid, hypoechoic, painless, and highly vascularized left parauterine mass was identified. On histological examination, a uterine smooth muscle tumor of uncertain malignant potential (STUMP) with intravascular invasion of the left uterine vein was diagnosed. The adnexa and peritoneum were free of disease. On a retrospective evaluation of the ultrasound images, we noticed that the intravascular lesion showed sonographic features comparable to the original mass. Moreover, the Color Doppler (CD) analysis revealed an interrupted blood flow within the left uterine vein. In this case, the ultrasound proved to be an accurate diagnostic tool. When inhomogeneous uterine masses are suspected, and a parauterine/paraadnexal mass surrounded by irregular vessels are identified, the sonographer should take into account a risk of intravascular invasion. The patency of uterine and ovarian vessels should be accurately evaluated, to guide a tailored patient surgical approach.

Ultrasound features using MUSA terms and definitions in uterine sarcoma and leiomyoma: cohort study

OBJECTIVES

Timely and accurate preoperative diagnosis of uterine sarcoma will increase patient survival. The primary aim of this study was to describe the ultrasound features of uterine sarcoma compared with those of uterine leiomyoma based on the terms and definitions of the Morphological Uterus Sonographic Assessment (MUSA) group. A secondary aim was to assess the interobserver agreement for reporting on ultrasound features according to MUSA terminology.

METHODS

This was a retrospective cohort study of patients with uterine sarcoma or uterine leiomyoma treated in a single tertiary center during the periods 1997-2019 and 2016-2019, respectively. Demographic characteristics, presenting symptoms and surgical outcomes were extracted from patients' files. Ultrasound images were re-evaluated independently by two sonologists using MUSA terms and definitions. Descriptive statistics were calculated and interobserver agreement was assessed using Cohen's κ (with squared weights) or intraclass correlation coefficient, as appropriate.

RESULTS

A total of 107 patients were included, of whom 16 had a uterine sarcoma and 91 had a uterine leiomyoma. Abnormal uterine bleeding was the most frequent presenting symptom (69/107 (64%)). Compared with leiomyoma cases, patients with uterine sarcoma were older (median age, 65 (interquartile range (IQR), 60-70) years vs 48 (IQR, 43-52) years) and more likely to be postmenopausal (13/16 (81%) vs 15/91 (16%)). In the uterine sarcoma cohort, leiomyosarcoma was the most frequent histological type (6/16 (38%)), followed by adenosarcoma (4/16 (25%)). On ultrasound evaluation, according to Observers 1 and 2, the tumor border was irregular in most sarcomas (11/16 (69%) and 13/16 (81%) cases, respectively), but regular in most leiomyomas (65/91 (71%) and 82/91 (90%) cases, respectively). Lesion echogenicity was classified as non-uniform in 68/91 (75%) and 51/91 (56%) leiomyomas by Observers 1 and 2, respectively, and 15/16 (94%) uterine sarcomas by both observers. More than 60% of the uterine sarcomas showed acoustic shadows (11/16 (69%) and 10/16 (63%) cases by Observers 1 and 2, respectively), whereas calcifications were reported in a small minority (0/16 (0%) and 2/16 (13%) cases by Observers 1 and 2, respectively). In uterine sarcomas, intralesional vascularity was reported as moderate to abundant in 13/16 (81%) cases by Observer 1 and 15/16 (94%) cases by Observer 2, while circumferential vascularity was scored as moderate to abundant in 6/16 (38%) by both observers. Interobserver agreement for the presence of cystic areas, calcifications, acoustic shadow, central necrosis, color score (overall, intralesional and circumferential) and maximum diameter of the lesion was moderate. The agreement for shape of lesion, tumor border and echogenicity was fair.

CONCLUSIONS

A postmenopausal patient presenting with abnormal uterine bleeding and a new or growing mesenchymal mass with irregular tumor borders, moderate-to-abundant intralesional vascularity, cystic areas and an absence of calcifications on ultrasonography is at a higher risk of having a uterine sarcoma. Interobserver agreement for most MUSA terms and definitions is moderate. Future studies should validate the abovementioned clinical and ultrasound findings on uterine mesenchymal tumors in a prospective multicenter fashion. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Uterine smooth muscle tumors: a multicenter, retrospective, comparative study of clinical and ultrasound features

OBJECTIVE

To evaluate a wide range of clinical and ultrasound characteristics of different uterine smooth muscle tumors to identify features capable of discriminating between these types.

METHODS

This was a retrospective, multicenter study that included 285 patients diagnosed with uterine smooth muscle tumors (50 leiomyosarcomas, 35 smooth muscle tumors of uncertain malignant potential, and 200 leiomyomas). The patients were divided into three groups based on the histological type of their tumors, and the groups were compared according to the variables collected.

RESULTS

Leiomyosarcomas were more common in older and post-menopausal women. Compared with leiomyomas, smooth muscle tumors of uncertain malignant potential and leiomyosarcomas had similar ultrasound features such as absence of normal myometrium, multilocular appearance, hyper-echogenicity in case of uniform echogenicity, absence of posterior shadows, echogenic areas, and hyperechoic rim. Leiomyosarcomas were larger, had more cystic areas, and were associated with a higher prevalence of pelvic free fluid. Smooth muscle tumors of uncertain malignant potential were characterized by a higher frequency of International Federation of Gynecology and Obstetrics (FIGO) type 6-7, the absence of internal shadows, and, in the case of cystic area, the presence of a regular internal wall. Tumor outline varied among the three histological types. A color score of 1 was typical of leiomyoma, a color score 2 was mainly observed in leiomyomas and smooth muscle tumors of uncertain malignant potential, a color score 3 did not differ among the tumors, while a color of score 4 was related to leiomyosarcomas. When combining color scores 3 and 4, leiomyosarcomas and smooth muscle tumors of uncertain malignant potential showed a high percentage of both circumferential and intra-lesional vascularization. A cooked appearance was not statistically different among the tumors.

CONCLUSIONS

Based on our findings, specific ultrasonographic features as well as age and menopausal status are associated with different uterine smooth muscle tumor types. Integration of these data can help the pre-operative assessment of these lesions for proper management.

Uterine Tumors Resembling Ovarian Sex Cord Tumors (UTROSCTs): A Scoping Review of 511 Cases, Including 2 New Cases

Uterine Tumors Resembling Ovarian Sex Cord Tumors (UTROSCTs) are rare uterine mesenchymal neoplasms with uncertain biological potential. These tumors, which affect both premenopausal and postmenopausal women, usually have a benign clinical course. Nevertheless, local recurrences and distant metastases have been described. By analyzing 511 cases retrieved from individual reports and cases series, we provide here the most comprehensive overview of UTROSCT cases available in the literature, supplemented by two new cases of UTROSCTs. Case 1 was an asymptomatic 31-year-old woman who underwent a laparoscopic resection of a presumed leiomyoma. Case 2 was a 58-year-old postmenopausal woman with abnormal vaginal bleeding who underwent an outpatient hysteroscopic biopsy of a suspicious endometrial area. In both cases, immunohistochemical positivity for Calretinin and Inhibin was noted, typical for a sex cord differentiation. In both cases, total laparoscopic hysterectomy with bilateral salpingo-oophorectomy was performed. In light of the available literature, no pathognomonic clinical or imaging finding can be attributed to UTROSCT. Patients usually present with abnormal uterine bleeding or pelvic discomfort, but 20% of them are asymptomatic. In most cases, a simple hysterectomy appears to be the appropriate treatment, but for women who wish to become pregnant, uterus-preserving approaches should be discussed after excluding risk factors. Age, tumor size, lymphovascular space invasion, nuclear atypia, and cervical involvement are not reliable prognostic factors in UTROSCT. The current research suggests that aggressive cases (with extrauterine spread or recurrence) can be identified based on a distinct genetic and immunohistochemical phenotype. For instance, UTROSCTs characterized by GREB1::NCOA1-3 fusions and PD-L1 molecule expression appear to be predisposed to more aggressive behaviors and recurrence, with GREB1::NCOA2 being the most common gene fusion in recurrent tumors. Hence, redefining the criteria for UTROSCTs may allow a better selection of women suitable for fertility-sparing treatments or requiring more aggressive treatments in the future.

US, MRI, CT Performance and Interpretation of Uterine Masses

Uterine masses are commonly encountered as incidental findings during cross-sectional imaging or when individuals present with symptoms such as pain and bleeding. The World Health Organization categorizes tumors of the uterine corpus into 5 distinct groups: endometrial epithelial tumors and their precursors, tumor-like growths, mesenchymal uterine tumors, tumors with a combination of epithelial and mesenchymal elements, and various other types of tumors. The primary imaging method for assessing uterine abnormalities is transvaginal ultrasound. However, magnetic resonance imaging (MRI) can be employed to enhance the visualization of soft tissues, enabling a more detailed characterization of uterine masses. This article aims to outline the imaging features of both benign and malignant uterine masses using ultrasound, MRI, and computed tomography.

Smooth Muscle Tumor of Uncertain Malignant Potential (STUMP): A Comprehensive Multidisciplinary Update

Background and Objectives: The uterine smooth muscle tumors of uncertain malignant potential (STUMP) are tumors with pathological characteristics similar to leiomyosarcoma, but that do not satisfy histological criteria for leiomyoma. These are problematic lesions with intermediate morphologic features; thus, diagnosis and treatment are difficult. This narrative review aims to review data in the literature about STUMPs, particularly focusing on management and therapeutic options and strategies for women who desire to preserve fertility. Material and Methods: authors searched for "uterine smooth muscle tumor of uncertain malignant potential" in PubMed and Scopus databases, from 2000 to March 2023. Pertinent articles were obtained in full-text format and screened for additional references. Only articles in English language were included. Studies including full case description of patients with histopathological diagnosis of STUMP in accordance with Stanford criteria were included. Results: The median age was 43 years old. Symptoms are similar to those of leiomyomas, with a mean diameter of 8.0 cm. Total hysterectomy with or without bilateral salpingo-oophorectomy is the standard care for women if fertility desire is satisfied. Myomectomy alone can be considered for young patients. Although these tumors have not a high malignant potential, several studies described recurrence and metastases. Conclusions: STUMPs are complex uterine smooth muscle tumors, with a rare but reasoned clinical-diagnostic management. Considering the high clinical and histological complexity of these tumors, high level of expertise is mandatory.

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.

Sonographic characterization and surveillance of paravaginal smooth muscle tumor of uncertain malignant potential

Sonographic characterization and surveillance of paravaginal smooth muscle tumor of uncertain malignant potential. (A1) Transvaginal ultrasound with probe placed over the right vaginal wall, showing a well-defined round mass with regular contours, a mostly hypoechoic and heterogeneous echotexture, and edge shadowing, deep to the right distal third of the right vagina. (A2) Multifrequency linear probe (9-14 MHz) placed over the right labium majus revealing hyperechoic striations (arrows on A1-A2) and central flow (arrowheads on A2). (B1) Resected solid white-tan mass of bland consistency. (B2) Hematoxylin-eosin microscopy (40X) showing fusiform cells, with mild to moderate atypia. (C1) Repeat transvaginal ultrasound six-years later showing a recurrent solid oval-shaped mass with regular contour, a mostly hypoechoic heterogeneous echotexture, and an anechoic area inside the solid mass (asterisk on C2) that could represent a focus of necrosis.

Clinical and Histopathological Predictors of Recurrence in Uterine Smooth Muscle Tumor of Uncertain Malignant Potential (STUMP): A Multicenter Retrospective Cohort Study of Tertiary Centers

BACKGROUND

The term uterine smooth muscle tumor of uncertain malignant potential (STUMP) indicates a rare, equivocal entity between benign leiomyomas and leiomyosarcomas. In the present study, we evaluated a comprehensive range of clinical, surgical, and pathological features in a large multicenter series of patients with STUMP to identify risk factors for recurrence.

METHODS

This is a retrospective study performed by collecting consecutive cases diagnosed between January 2000 and December 2020 in five tertiary centers. Associations between STUMP recurrence and clinicopathological characteristics as well as surgical treatment modality were investigated.

RESULTS

Eighty-seven patients affected by STUMP were considered. Of them, 18 cases (20.7%) recurred: 11 as leiomyosarcoma (LMS) and 7 as STUMP. The mean time to recurrence was 79 months. We found that fragmentation/morcellation, epithelioid features, high mitotic count, Ki-67 value > 20%, progesterone receptor (PR) < 83%, and p16 diffuse expression were associated with higher risk of recurrence and shorter recurrence-free survival (RFS). Furthermore, morcellation/fragmentation and mitotic count remained independent risk factors for recurrence and shorter RFS after multivariate analysis, while the presence of epithelioid features was an independent risk factor for recurrence only.

CONCLUSIONS

Our results suggest that morcellation is associated with risk of recurrence and shorter RFS, thus it should be avoided if a STUMP is suspected preoperatively. Epithelioid features, high proliferation activity, low PR expression, and diffuse p16 expression are also unfavorable prognostic factors, so patients presenting these features should be closely followed up.