Uterine smooth muscle tumors other than the ordinary leiomyomas and leiomyosarcomas: a review of selected variants with emphasis on recent advances and unusual morphology that may cause concern for malignancy

Genomic characterization and histologic analysis of uterine leiomyosarcoma arising from leiomyoma with bizarre nuclei

Leiomyoma with bizarre nuclei (LM-BN) is a rare variant of leiomyoma with a benign clinical course. In contrast, leiomyosarcoma (LMS) is a high-grade, malignant neoplasm characterized by high recurrence rates and poor survival. While LM-BN and LMS show distinct morphologies, they share similar immunoprofiles and molecular alterations, with both considered 'genomically unstable'. Rare cases of LM-BN associated with LMS have been reported; however, the histogenesis and molecular relationship between these two tumors remains unclear. In this study, we assessed 11 cases of LMS arising in conjunction with LM-BN confirmed by histology and immunohistochemistry (IHC), further analyzed by clinical, histologic, and molecular characteristics of these distinct components. LM-BN and LMS had similar p16 and p53 IHC patterns, but LMS had a higher Ki-67 index and lower estrogen and progesterone eceptor expression. Digital image analysis based on cytologic features revealed spatial relationships between LMS and LM-BN. Genomic copy number alterations (CNAs) demonstrated the same clonal origin of LMS arising from existing LM-BN through conserved CNAs. LMS harbored highly complex CNAs and more frequent losses of the TP53, RB1, and PTEN genomic regions than LM-BN (p = 0.0031), with CDKN2A/B deletion identified in LMS only. Mutational profiling revealed many shared oncogenic alterations in both LM-BN and LMS; however, additional mutations were present within LMS, indicative of tumor progression through progressive genomic instability. Analysis of spatial transcriptomes defined uniquely expressed gene signatures that matched the geographic distribution of LM-BN, LMS, and other cell types. Our findings indicate for the first time that a subset of LMS arises from an existing LM-BN, and highly complex genomic alterations could be potential high risks associated with disease progression in LM-BN. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Pulmonary metastases of a uterine smooth muscle tumor of uncertain malignant potential presenting as growing bullae: a case report

Postoperative recurrences of uncertain malignant potential [(smooth muscle tumors of uncertain malignant potential (STUMPs)] have been reported, with lung as the most common site. Herein, we describe pulmonary metastases of a uterine STUMP presenting as bullae in a female patient. Computed tomography revealed two pulmonary metastases in the left lung with several bullae in both lungs, and the patient was referred to our department for pulmonary metastasectomy. Despite mild right pneumothorax on admission, left pulmonary metastasectomy and bullectomy were safely performed, with an uneventful postoperative course. Right pneumothorax recurred four days after discharge; hence, surgery was indicated. Although the air leak point was not a bulla but rather a pleural dissemination nodule, metastasectomy with bullectomy was performed. Pathological examination suggested that the bullae developed owing to retraction and collapse of the alveoli surrounding the pulmonary metastases. Bullae formed during the clinical course of malignancy have the potential of pulmonary metastases.

Uterine Smooth Muscle Tumors: An Overview

Uterine smooth muscle tumors are a heterogeneous group of mesenchymal neoplasms with multiple histologic variants and distinct biological behaviors. Pathologic classification (benign, uncertain malignant potential, malignant) relies on the evaluation of mitotic index, necrosis, and degree of cytologic atypia, with different thresholds based on each subtype. Immunohistochemistry and other ancillary studies may be necessary to establish the diagnosis in a subset of cases, given the morphologic overlap with other mesenchymal neoplasms, including low-grade and high-grade endometrial stromal tumors, inflammatory myofibroblastic tumors, and PEComa. Recent advances in molecular diagnostics have refined the classification of smooth muscle tumors, but most cases are diagnosed purely on histologic grounds.

Challenges Associated with Smooth Muscle Tumor of Uncertain Malignant Potential (STUMP) Management-A Case Report with Comprehensive Literature Review

Background: Smooth Muscle Tumor of Uncertain Malignant Potential (STUMP) is a poorly studied neoplasm that does not fulfill the definition of either leiomyoma or leiomyosarcoma. STUMP symptoms are indistinguishable from those of benign lesions; it has no specific biochemical markers or ultrasound presentations. The management of this type of tumor is particularly challenging due to significant heterogeneity in its behavior and the lack of clear guidelines; moreover, the lesion may recur after excision. Case Report: We report on a case of a 42-year-old patient diagnosed with a STUMP. The preliminary diagnosis was a submucous leiomyoma, which was removed hysteroscopically due to menorrhagia resulting in anemia. The histopathological examination of the resected myoma pointed to the diagnosis of STUMP. The hysterectomy was performed as the patient had completed her reproductive plans. There were no complications. The patient is currently recurrence-free after a 9-month follow-up. Discussion and Conclusions: The care of a patient diagnosed with STUMP requires a personalized approach and the cooperation of various medical disciplines, including molecular diagnostics, imaging techniques, and minimally invasive surgery. Management of STUMP must consider the patient's plans for childbearing. All cases of tumors with "uncertain malignant potential" are a challenge in the context of patient-physician communication.

Smooth Muscle Tumor of Uncertain Malignant Potential (STUMP): A Systematic Review of the Literature in the Last 20 Years

Smooth Muscle Tumor of Uncertain Malignant Potential (STUMP) is a rare uterine tumor primarily affecting perimenopausal and postmenopausal women, typically aged between 45 and 55 years. Characterized by ambiguous histological features, STUMPs present diagnostic challenges as they cannot be definitively classified as benign or malignant based on morphology alone. This systematic review aims to elucidate the clinical, pathological, immunohistochemical, and treatment-related characteristics of STUMPs through an analysis of the literature from the past 20 years. The study follows PRISMA guidelines, utilizing comprehensive searches of PubMed and Scopus databases, yielding 32 studies that meet the inclusion criteria. From the analysis of these studies, it was revealed that the clinical presentations vary from common symptoms such as abnormal uterine bleeding and pelvic pain to incidental detection of uterine mass. Histologically, STUMPs demonstrate features overlapping with both leiomyomas and leiomyosarcomas, including mild nuclear atypia, low mitotic indices, and focal necrosis. Immunohistochemical markers such as p16 and p53 have been investigated for prognostic significance. Elevated p16 expression, often associated with aggressive behavior, was observed in a subset of STUMPs. Surgical management, typically involving hysterectomy or tumorectomy, is the primary treatment, though the extent of resection is variable. Adjuvant therapies are not routinely recommended, but long-term surveillance is advised, especially for high-risk patients. Recurrence rates for STUMPs are approximately 12%, with factors such as high mitotic counts and coagulative necrosis indicating higher risk. This review highlights the complexity of STUMP diagnosis and management, emphasizing the need for more precise diagnostic criteria and individualized treatment strategies. Understanding the morphological, immunohistochemical, and clinical behavior of STUMPs can improve patient outcomes and guide future research in this diagnostically challenging area.

Case report: Spontaneous rupture of leiomyosarcoma uteri 8 months after primary laparoscopic surgery of STUMP

Introduction

Leiomyosarcoma (LMS), together with smooth muscle tumors of uncertain malignant potential (STUMP) and benign leiomyomas, belongs to a heterogeneous group of uterine neoplasms. According to the World Health Organization, tumors originating from uterine smooth muscle fibers are the second most frequent tumors. It is challenging to distinguish between STUMP and LMS because of an overlap of symptoms, lack of a precise definition, and unequivocal information obtained using imaging diagnostic methods. Following myomectomy or hysterectomy with laparoscopic or laparotomy surgery and a definitive histological diagnosis of STUMP, the course of treatment is determined by the need to preserve fertility. In 2014, the U.S. Food and Drug Administration published an alert that unprotected laparoscopic morcellation is correlated with a 3-fold higher likelihood of dissemination of malignant cells and disease progression. Unprotected morcellation was independently associated with a higher risk of disease recurrence after demolition or conservative surgery, with a relative risk of 2.94.

Conclusion

Hematoperitoneum resulting from the spontaneous rupture of a uterine tumor is a rare gynecological emergency, with very few cases reported in the last decade.

FTIR Microspectroscopy as a new probe to study human uterine lesions: Characterization of tumor cell lines from uterine smooth muscle cells and evaluation of EPA and DHA in vitro treatments

During their life, women are likely to develop uterine diseases, which often compromise their fertile and perimenopausal age. Besides benign lesions like leiomyomas, several malignant neoplasms can occur, such as the uterine leiomyosarcoma, which represents the most frequent malignancy among the rarest uterine cancers. It presents several variants similar to both benign and malignant neoplasms, and sometimes it shares symptoms with the benign counterpart. In this scenario, for a correct diagnosis and a successful prognosis, it is mandatory to detect new reliable markers which strengthen histopathological outcomes and let define a more appropriate and less harmful therapy. Based on this concerning evidence, in the present study, Fourier Transform Infrared Microspectroscopy has been exploited at a cellular level on uterine leiomyoma and leiomyosarcoma cell lines to (1) identify specific spectral biomarkers able to distinguish between benign and malignant lesions, and (2) evaluate the efficacy of eicosapentaenoic and docosahexaenoic acids (respectively EPA and DHA), already successfully tested. Results evidenced reliable differences in the spectral signature of benign and malignant cells, mainly in terms of lipids and nucleic acids composition. Moreover, even if EPA and DHA seemed to exert different effects on the tested cell lines, no cytotoxic and/or anti-apoptotic actions were observed after omega-3 based treatments.

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.

A Review and Follow-Up of Uterine Smooth Muscle Tumours of Uncertain Malignant Potential (STUMP): A Case Series and Literature Review

OBJECTIVES

to analyse the clinical-pathological characteristics, treatment, and evolution of uterine smooth muscle tumours with uncertain malignant potential (STUMP) diagnosed in the Salamanca University Hospital with the implementation of the 2014 WHO criteria.

MATERIALS AND METHODS

a retrospective descriptive study of patients diagnosed with STUMP from January 2015 to March 2023 at the Salamanca University Hospital. Demographic data, preoperative clinical data, treatment, complications, therapeutic results, anatomopathological findings and recurrence time were obtained.

RESULTS

a total of four patients were identified and included in the study. The mean age at diagnosis was 48 years (range 36-67). The surgical indications were abnormal uterine bleeding, compressive symptoms, and the growth of a pelvic mass suspected to be a degenerated myoma from the residual cervix after a subtotal hysterectomy 6 years earlier. In all cases, a laparotomic procedure was performed. A total hysterectomy, sub-total hysterectomy, and the excision of the cervix with STUMP localization were accomplished in two, one, and one patient, respectively. The mean diameter of the tumour pieces was 13 cm (range 8-17 cm), with a mean volume of 816 cc (range 234-1467 cc). The mean follow-up was 47 months, with no recurrence to date.

CONCLUSIONS

STUMPs are a heterogeneous group of tumours with a difficult-to-predict clinical evolution. In most cases, their diagnosis is histological after performing surgery for suspected leiomyoma. Due to their low incidence, there are no specific guidelines for their treatment and control. However, considering their potential risk of recurrence and metastasis, it is advisable to maintain six-monthly controls for 5 years and then annual controls for 5 years more.

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.

The Role of Pathogenesis Associated with the Tumor Microclimate in the Differential Diagnosis of Uterine Myocytic Tumors

Myocytic tumors of the uterus present vast morphological heterogeneity, which makes differential diagnosis between the different entities necessary. This study aims to enrich the existing data and highlight new potential therapeutic targets regarding aspects related to the pathogenic process and the tumor microenvironment in order to improve the quality of life of women. We performed a 5-year retrospective study, including particular cases of uterine myocyte tumors. Immunohistochemical analyses of pathogenic pathways (p53, RB1, and PTEN) and tumor microclimate using markers (CD8, PD-L1, and CD105), as well as genetic testing of the PTEN gene, were performed. The data were statistically analyzed using the appropriate parameters. In cases of atypical leiomyoma, a significant association was observed between PTEN deletion and an increased number of PD-L1+ T lymphocytes. For malignant lesions and STUMP, PTEN deletion was associated with the advanced disease stage. Advanced cases were also associated with an increased mean CD8+ T cell count. An increased number of lymphocytes was associated with an increased percentage of RB1+ nuclei. The study corroborated clinical and histogenetic data, highlighting the importance of the differential diagnosis of these tumors to improve the management of patients and increase their quality of life.

Laterally extended endopelvic resection as part of the surgical management of disseminated retroperitoneal leiomyomatosis mimicking low-grade sarcoma in a patient with a solitary kidney

Leiomyomas are common benign uterine smooth muscle tumours. Rarer subsets may demonstrate aggressive extrauterine growth which mimic metastatic disease. We discuss the case of a female patient in her 40s, with a long-standing atrophic right kidney, presenting with a 17 cm uterine mass demonstrating bilateral para-aortic and pelvic sidewall spread. Although biopsies favoured the diagnosis of a benign tumour, a leiomyosarcoma could not be excluded. The surgical complexity of the case was compounded by a tumour residing close to the only functioning kidney and engulfment of the inferior mesenteric artery. The surgical procedures indicated were a radical hysterectomy, the laterally extended endopelvic resection procedure to achieve clear margins in the pelvic sidewall and a left hemicolectomy. In the absence of formal guidelines, we present this challenging case to provide clarity into the histological assessment and surgical management of rare leiomyomas, as well as an overview of the current literature.

Rare case of retroperitoneal mitotically active leiomyoma in a postmenopausal woman

Leiomyomas are benign smooth muscle tumors, and retroperitoneal leiomyomas without coexisting uterine leiomyomas are extremely rare. Mitotically active leiomyomas, which are leiomyomas with increased mitotic activity, are rarely observed in postmenopausal women, except under the influence of exogenous hormones. This report presents a rare case of a retroperitoneal mitotically active leiomyoma in a postmenopausal woman. The patient presented with an abdominal mass and underwent surgical resection of the retroperitoneal tumor. Pathological examination revealed a mitotically active retroperitoneal leiomyoma with 31 mitotic figures per 10 high-power fields. The patient did not experience recurrence during the 2-year follow-up period. This case highlights the need to consider retroperitoneal mitotically active leiomyomas in postmenopausal women and suggests that myomectomy can prevent their recurrence.

The incidence of neoplasm of uncertain behavior of uterus diagnosed after surgery for presumed leiomyoma: A national population-based study

OBJECTIVE

To investigate the incidence of neoplasm of uncertain behavior of uterus (NUBU) diagnosed after hysterectomy, myomectomy, or hysteroscopy for presumed leiomyomas.

METHODS

We performed this population-based retrospective cohort study using the Korean national health insurance database between January 2002 and December 2018. Women with or without NUBU diagnosed after surgery were extracted using diagnosis codes and procedure codes.

RESULTS

The median age of patients who underwent surgery for presumed leiomyomas was 39 years (interquartile range [IQR] 31-47 years). The median age of women diagnosed with NUBU after surgery was 45 years (IQR 38-49 years). The incidence of NUBU diagnosed after surgery for presumed leiomyomas was 1.89%. The incidences of NUBU diagnosed after hysterectomy, myomectomy, or hysteroscopic myomectomy for presumed leiomyomas were 2.03%, 1.84%, or 1.64%, respectively. There was no difference in the incidence of NUBU according to these surgical methods.

CONCLUSIONS

Regardless of the surgical procedure performed, the incidence of NUBU diagnosed after surgery was higher than that of unexpected uterine malignancy diagnosed after hysterectomy (0.19%), myomectomy (0.12%), or hysteroscopic myomectomy (0.86%) for presumed leiomyoma. Compared with unexpected uterine malignancy, NUBU seems to occur in relatively young women.

MRI Evaluation of Uterine Masses for Risk of Leiomyosarcoma: A Consensus Statement

Laparoscopic myomectomy, a common gynecologic operation in premenopausal women, has become heavily regulated since 2014 following the dissemination of unsuspected uterine leiomyosarcoma (LMS) throughout the pelvis of a physician treated for symptomatic leiomyoma. Research since that time suggests a higher prevalence than previously suspected of uterine LMS in resected masses presumed to represent leiomyoma, as high as one in 770 women (0.13%). Though rare, the dissemination of an aggressive malignant neoplasm due to noncontained electromechanical morcellation in laparoscopic myomectomy is a devastating outcome. Gynecologic surgeons' desire for an evidence-based, noninvasive evaluation for LMS is driven by a clear need to avoid such harms while maintaining the availability of minimally invasive surgery for symptomatic leiomyoma. Laparoscopic gynecologists could rely upon the distinction of higher-risk uterine masses preoperatively to plan oncologic surgery (ie, potential hysterectomy) for patients with elevated risk for LMS and, conversely, to safely offer women with no or minimal indicators of elevated risk the fertility-preserving laparoscopic myomectomy. MRI evaluation for LMS may potentially serve this purpose in symptomatic women with leiomyomas. This evidence review and consensus statement defines imaging and disease-related terms to allow more uniform and reliable interpretation and identifies the highest priorities for future research on LMS evaluation.

Hemoperitoneum due to spontaneous bleeding from a smooth muscle tumor of uncertain malignant potential: A rare case report

INTRODUCTION AND IMPORTANCE

Smooth muscle tumors of uncertain malignant potential (STUMPs) are uncommon tumors representing an extremely rare cause of hemoperitoneum.

CASE PRESENTATION

We report a case of a 48-year-old Caucasian, premenopausal woman that presented in the emergency department with acute abdominal pain. There was no remarkable past medical and surgical history except from a known uterine leiomyoma. The ultrasound and the computed tomography imaging showed an intraperitoneal fluid collection and a heterogenous uterine mass. The patient underwent emergent exploratory laparotomy; a subserosal uterine tumor was identified with an actively bleeding vessel on its surface. The uterine lesion was completely excised and the histopathology set the diagnosis of a STUMP. After consultation on the significance of this finding with the patient, an abdominal total hysterectomy and bilateral salpingo-oophorectomy were scheduled and performed and the subsequent histopathology detected no malignancy.

CLINICAL DISCUSSION

This case demonstrates that a STUMP may be a rare cause of acute intraperitoneal bleeding. Careful evaluation of clinical history, imaging findings and, if needed, surgical exploration are important for the diagnosis, while appropriate follow-up is also of major importance for the management of these rare tumors.

CONCLUSION

We presented an extremely rare case of hemoperitoneum due to spontaneous bleeding from a STUMP. From an oncological perspective, this case poses a diagnostic, management and follow-up challenge.

Loss of dystrophin is common in uterine leiomyosarcoma: a potential biomarker for clinical application

Uterine leiomyosarcoma (LMS) is a deadly disease with high rates of recurrence and a poor prognosis. Its tumorigenesis remains largely unknown, and no specific biomarkers can be used for the differential diagnosis of LMS from other mimics. Recent whole-genome studies revealed a loss of dystrophin is common in LMS, especially in uterine LMS. To investigate the expression pattern of dystrophin expression across different types of uterine smooth muscle tumors, immunohistochemistry was performed, including usual-type leiomyoma, fumarate hydratase-deficient leiomyoma, leiomyoma with bizarre nuclei, conventional LMS, and normal myometrium for this study. To further evaluate the genomic change in dystrophin gene region, whole-genome sequencing in 10 LMS cases were analyzed. Dystrophin expression was detected in 94% (45/48) of myometrium, 97% (34/35) of usual-type leiomyoma, 84% (26/31) of fumarate hydratase-deficient leiomyoma, 60% (12/20) of leiomyoma with bizarre nuclei, and 18% (6/34) of LMS. Loss of dystrophin expression was significantly different between benign and malignant tumors (LMS cases counted as malignant only) (p < 0.01). Of note, copy number loss in the dystrophin genomic region was found in all 10 cases of LMS. Additionally, patients with dystrophin-positive LMS tend to have a better overall survival than patients with dystrophin-negative LMS.

Five-Year Retrospective Study of Uterine STUMP and Leiomyosarcoma

Taking into account the unpredictable evolution of uterine STUMP and leiomyosarcomas, there are no clearly established therapeutic protocols to date, the only certified treatment being total hysterectomy. We performed a 5-year retrospective study including cases of malignant tumors and those with uncertain malignant potential originating in the smooth muscle tissue of the uterine body. The clinical data, pathological aspects, and the immunohistochemical results were statistically analyzed using SPSS Statistics Version 26. The main associations of the p53 gene were identified with age, atypia, and the occurrence of metastases. The average number of CD8+ T cells correlated with the hormonal status of the patients, the presence of diabetes, and alteration of thyroid function, but also with the severity of the atypia. The therapeutic method was represented by total hysterectomy, and 30% of the patients with leiomyosarcoma also benefited from adjuvant chemotherapy. The average period until death was 25.66 months. The present study showed that the mutant expression of p53 could have a role in assessing the clinical evolution of patients, given the association with exitus and metastasis. In addition, the average number of CD8+ T cells corresponded to severe atypia, indicating the possibility of applying targeted immunotherapies in these cases.

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.

Uterine Leiomyosarcoma Associated With Leiomyoma With Bizarre Nuclei: Histology and Genomic Analysis of 2 Cases

Leiomyoma with bizarre nuclei (LM-BN) is a rare variant of leiomyoma with overall benign clinical course. It has histologic features showing focal or diffuse nuclear atypia surrounded by usual type leiomyoma. Uterine leiomyosarcomas (LMS) are a group of rare and aggressive malignancies with limited treatment options available. The potential association between LM-BN with LMS is largely unknown. In this study, we report 2 cases of uterine smooth muscle tumor with typical histologic and molecular evidence of LM-BN, which are associated with its progression to the malignant counterpart of LMS. We summarize the detailed histologic, morphologic, and genomic characteristics of these 2 sets of cases. Our findings suggest that LMS progressing from preexisting LM-BN can be one of the tumor pathogenesis pathways in uterine leiomyosarcomas.

Management of a giant uterine smooth muscle tumor of uncertain malignant potential in a 32-year-old woman: case report and review of the literature

Uterine smooth muscle tumors of uncertain malignant potential (STUMP) represent a group of rare uterine smooth muscle tumors not diagnosed unequivocally as benign or malignant. To data, diagnostic criteria, malignant potential, surgical management, and follow-up of these neoplasms remain controversial. Considering that STUMP and leiomyoma are not significantly different in terms of clinical presentation and preoperative sonographic characteristics, it might be difficult to distinguish between the two affections prior to pathological confirmation at surgery. All cases should be managed by multidisciplinary tumor teams and patients' follow-up should comprise consultation with a gynecologic oncologist and a close surveillance because of the possibility of recurrence or metastasis. We present the case of a 32-year-old nulliparous woman admitted to our gynecology clinic. She was asymptomatic and only complained an increase in abdominal volume started during the past 6 months. A transabdominal and transvaginal pelvic ultrasound revealed a large heterogeneous tumor mass measuring 190×163 mm, color score 2, expanded in the left iliac fossa, suspected for benign uterine myoma. Subsequent magnetic resonance imaging confirmed a large pelvic-abdominal tumor located near the left posterior-lateral uterine wall with areas of necrosis, suggestive of subserosal leiomyoma with cystic degeneration. The patient underwent a median longitudinal laparotomy for excision of the pelvic mass. The patient was normally discharged five days after surgery in good health conditions. The final histological examination was compatible with STUMP. At present, the patient has had no relapses or metastases and she is undergoing follow-up.

Uterine fibroid-like tumors: spectrum of MR imaging findings and their differential diagnosis

Uterine leiomyoma, also known as uterine fibroid, is the most common gynecological tumor, affecting almost 80% of women at some point during their lives. In the same time, other fibroid-like tumors have similar clinical presentations and about 0.5% of resected tumors of which were presumed benign fibroids in the preoperative diagnosis revealed as malignant sarcomas in the final histopathological examination. Amid the emergence of nonsurgical or minimally invasive procedures for symptomatic benign uterine fibroids, such as uterine artery embolization, high-intensity-focused ultrasound, or laparoscopic myomectomy, the preoperative diagnosis of uterine tumors through imaging becomes all the more relevant. Preoperative tissue sampling is challenging because of the variable location of the myometrial mass; thus, the preoperative evaluation of size and location is increasingly performed through magnetic resonance imaging. Features in images might also be useful for examining the full spectrum of such growths, from benign fibroids to neoplasms of uncertain behavior and malignant sarcomas. Benign fibroids include usual-type leiomyomas, myomas with degeneration, and mitotically active leiomyomas. Neoplasms of uncertain behavior include smooth muscle tumors of uncertain malignant potential, leiomyomas with bizarre nuclei, and cellular leiomyomas. Malignant sarcomas comprise leiomyosarcomas, endometrial stromal sarcomas, adenosarcomas, and carcinosarcomas. The purpose of this article is to review the spectrum of MRI findings of uterine fibroid-like tumors, from benign variants, uncertain behavior to malignant sarcomas, and update the advanced imaging modalities, including diffusion-weighted imaging, positron emission tomography/computed tomography, combining texture analysis and radiomics, to tackle this important issue.

Multiple Leiomyomas in a Patient with Benign Metastasizing Leiomyoma: A Case Report

INTRODUCTION

Benign metastasizing leiomyoma (BML) is a rare disease and mostly affects females with a history of uterine leiomyoma, particularly the presence of multiple leiomyomas in BML patients is extremely rare.

CASE PRESENTATION

This paper reported the clinical and imaging data of a BML patient with multiple leiomyomas involving bilateral pulmonary, mediastinum, pericardium, spine, peritoneum, and left thigh. Multiple BML lesions exhibited consistent imaging examinations, significantly improving the delayed phase enhancement. After multi-stage targeted therapy for multiple systemic metastases and the development of drug resistance, the patient was treated with hysterectomy and bilateral adnexectomy along with letrozole-based endocrine therapy. BML lesions, both pulmonary and mediastinum, became significantly smaller than before.

CONCLUSION

This paper aims to analyze the imaging and clinical features of multiple leiomyomas in this BML case, thus strengthening the understanding of the rare type of leiomyoma for effective preoperative diagnosis and clinical treatment. Furthermore, it is noteworthy that gynecologists should avoid the manifestation of BML when performing uterine fibroids surgery.

Leiomyoma with nuclear atypia: Rare diseases that present a common diagnostic problem

Leiomyoma with nuclear atypia describes a group of uterine smooth muscle tumors with a wide range of histologic and clinical presentations and remarkable nuclear atypia. These include fumarate hydratase-deficient leiomyoma (FH-LM), intravenous leiomyomatosis (IV-LM), and leiomyoma with bizarre nuclei (LM-BN). Other uterine mesenchymal tumors, such as perivascular epithelioid tumor (PEComa) and inflammatory myofibroblastic tumors (IMFT) are the mimickers of leiomyoma with nuclear atypia. LM-BN is the primary tumor model with a long history in gynecologic pathology, but the histogenesis of LM-BN remains largely unknown. Differentiating LM-BN from other benign variants, tumors with uncertain malignant potential (STUMP), or fully malignant leiomyosarcoma (LMS) can be diagnostically challenging. Recent progress has improved the diagnosis of many types of leiomyoma with nuclear atypia based on their specific histology and molecular alterations. LM-BN is now a diagnosis of exclusion. In this article, I review the history of leiomyoma with nuclear atypia and compare the clinical, histologic, and molecular features of LM-BN with those of its mimics. In particular, I highlight the current progress made in molecular genetics and pitfalls in the diagnosis of different myogenic tumors with nuclear atypia.

Rare Case of Smooth Muscle Tumor of Uncertain Malignant Potential - Clinical Case

Introduction: Smooth muscle tumor of uncertain malignant potential (STUMP) still represents a medical and surgical challenge, being rare and hard to diagnose. Normally STUMP consists in a multitude of uterine tumors that do not meet the current histologic criteria for a specific malignant or benign tumor. Clinical, imagistic and laboratory investigations seem to only raise the presumptive diagnosis in these cases, the diagnosis being confirmed during histological examination of the post hysterectomy/myomectomy specimen. Case report: We present the case of a 50-year-old female patient who was examined for the first time for pelvic pain and sensation of increased pressure in the lower abdomen in June 2020. A gynecology consultation was performed, during which a large uterine mass was felt on vaginal digital examination combined with pelvic palpation. Further pelvic ultrasound examination revealed a voluminous tumor of the left ovary. Then, a magnetic resonance imaging was performed, which showed a large pelvi-abdominal tumor of probable ovarian origin with a mixt tissue type and cystic structure, the presence of pathological abdominal and pelvic lymph nodes, ascites with a suspicion of peritoneal carcinomatosis. The patient was referred to a tertiary center and the multidisciplinary team recommended surgical treatment. A total hysterectomy with bilateral oophorectomy and stadial lymphadenectomy was performed. After surgery, the patient had a favorable evolution and was discharged five days after the intervention in a good health condition. Macroscopic and histological examinations of the biopsy pieces showed morphological aspects of uterine smooth muscles tumors with uncertain malignancy potential/STUMP and multiple uterine leiomyomas. Discussion:Due to the rarity of these tumors, the scientific literature needs to be constantly updated in order to help physicians to correctly identify and treat this pathology. It is highly recommended to identify tumors with a high malignancy potential, so that the follow up will be sufficient to discover and treat recurrences before they become life-threatening. Conclusion:Smooth muscle tumor of uncertain malignant potential remains a difficult diagnosis due to uncertainty between malignancy and benign features. Treatment approaches are difficult in these cases and must always be in accordance with the patients' desire to maintain their reproductive functions and fertility. Recurrence of STUMP has been reported, therefore a close follow up of these patients must always be performed.

Intraoperative Frozen Section Biopsy of Uterine Smooth Muscle Tumors: A Clinicopathologic Analysis of 112 Cases With Emphasis on Potential Diagnostic Pitfalls

Frozen sections of uterine smooth muscle tumors are infrequently required, and related diagnostic difficulties are seldom discussed. We analyzed the clinicopathologic features of 112 frozen sections of uterine smooth muscle tumors and determined the accuracy, reasons for deferrals, and causes of interpretational errors. Most patients (median age, 45 y) presented with pelvic mass symptoms (53%). The main reasons for a frozen section examination were an abnormal gross appearance including loss of the usual whorled pattern of leiomyoma (36 cases, 32.1%), and intraoperative discovery of an abnormal growth pattern and extrauterine extension of a uterine tumor (28 cases, 25%). There were 9 leiomyosarcomas and 103 leiomyomas, including 18 benign histologic variants. An accurate diagnosis of malignancy was achieved in all leiomyosarcomas, with the exception of a myxoid leiomyosarcoma. In 99 cases (88%), the frozen section diagnosis concurred with the permanent section diagnosis (false positives, 0.9%; false negatives, 0%). Misinterpretation of stromal hyalinization as tumor cell necrosis in a leiomyoma with amianthoid-like fibers was a major discrepancy. Two minor discrepancies did not lead to a change in management. The diagnosis was deferred in 10 cases (8.9%) because of stromal alterations, unusual cellular morphology, uncertain type of necrosis, and abnormal growth patterns. Thus, although various stromal and cellular alterations can cause diagnostic uncertainty, leading to deferrals, frozen section diagnosis of uterine smooth muscle tumors has a high accuracy rate. While a definitive frozen section diagnosis of malignancy may be made when there is unequivocal atypia, indisputable mitotic figures, and tumor cell necrosis, it is important to remember that nonmyogenic mesenchymal tumors may also mimic uterine smooth muscle tumors. In a frozen section setting, it would be sufficient to issue a diagnosis of "malignant mesenchymal tumor." For tumors that do not meet the criteria for malignancy, issuing a frozen section diagnosis of "atypical mesenchymal tumor and defer the histologic subtyping to the permanent sections" is appropriate.

Uterine smooth muscle tumour of uncertain malignant potential and in vitro fertilization treatment in an infertile patient

The term smooth uterine muscle of uncertain malignant potential (STUMP) indicates a group of uterine smooth muscle tumours that cannot be diagnosed unequivocally as malignant but does not fulfil the criteria for leiomyoma, or its variants. In this case, we present a woman treated for infertility who presented with an asymptomatic cervical mass, diagnosed as STUMP after three cycles of controlled ovarian stimulation. We reviewed the literature with particular emphasis on the effects of STUMP upon fertility, up-to-date guidance regarding the management of patients’ wishing fertility-sparing approaches and obstetric outcomes. To the best of our knowledge, this is the first case report of STUMP in a patient that has undergone multiple in vitro fertilization treatments as well as the first to provide a putative biological basis for the efficacy of gonadotropin-releasing hormone agonists, in this patient group.

Development of a Multi-Institutional Prediction Model for Three-Year Survival Status in Patients with Uterine Leiomyosarcoma (AGOG11-022/QCGC1302 Study)

Simple Summary

Uterine leiomyosarcoma is an aggressive tumor and the current staging system cannot differentiate the patients into different prognostic groups. This leads to difficulty in predicting the patients’ outcomes and planning for adjuvant therapy. We aimed to develop a prediction model that can predict the chance of survival by the third year. In this article, we had used different statistical tests to identify five readily available clinicopathologic parameters to build the prediction model. Internal validation was performed with satisfactory accuracy. Such a prediction model might help to predict survival outcome, and guide future research on the treatment modality.

Abstract

Background: The existing staging systems of uterine leiomyosarcoma (uLMS) cannot classify the patients into four non-overlapping prognostic groups. This study aimed to develop a prediction model to predict the three-year survival status of uLMS. Methods: In total, 201 patients with uLMS who had been treated between June 1993 and January 2014, were analyzed. Potential prognostic indicators were identified by univariate models followed by multivariate analyses. Prediction models were constructed by binomial regression with 3-year survival status as a binary outcome, and the final model was validated by internal cross-validation. Results: Nine potential parameters, including age, log tumor diameter, log mitotic count, cervical involvement, parametrial involvement, lymph node metastasis, distant metastasis, tumor circumscription and lymphovascular space invasion were identified. 110 patients had complete data to build the prediction models. Age, log tumor diameter, log mitotic count, distant metastasis, and circumscription were significantly correlated with the 3-year survival status. The final model with the lowest Akaike’s Information Criterion (117.56) was chosen and the cross validation estimated prediction accuracy was 0.745. Conclusion: We developed a prediction model for uLMS based on five readily available clinicopathologic parameters. This might provide a personalized prediction of the 3-year survival status and guide the use of adjuvant therapy, a cancer surveillance program, and future studies.

Clinical and reproductive outcomes of uterine smooth muscle tumor of uncertain malignant potential: a single-center retrospective study

OBJECTIVE

To evaluate the clinical outcomes, histopathological features, and obstetric and oncological outcomes of uterine smooth muscle tumor of uncertain malignant potential (STUMP).

METHODS

We conducted a single-center, database review of patients with STUMP between January 2001 and December 2015. We investigated the clinical, operative, histopathologic, recurrence, and fertility outcomes of the included cases.

RESULTS

Nineteen patients with STUMP were studied. Three were reclassified as sarcoma after slide review, and 16 patients were finally included in the study. The mean age was 45 years. Ki-67 expression was ≥10% in 25.0% of cases and 30% in the only recurrent case. Recurrence occurred 52 months after a diagnosis of STUMP in a 56-year-old female patient who underwent hysterectomy. Two of six patients who underwent myomectomy had fertility requirements, and both successfully delivered babies without recurrence. Recurrence was not related to mitosis, degree of atypia, or necrosis. There was also no relationship between type of surgery or surgical approach and recurrence.

CONCLUSIONS

Patients with STUMP warrant a pathological review process in centers with experience. Fertility-preservation is worth attempting, but young patients must be followed-up closely. Ki-67 might be a valuable marker predicting recurrence.

P16, Ki67, P53, and WT1 Expression in Uterine Smooth Muscle Tumors: An Adjunct in Confirming the Diagnosis of Malignancy in Ambiguous Cases

The diagnosis of uterine smooth muscle tumors is sometimes difficult, as these tumors may show worrisome features, suspicious for but not diagnostic of malignancy. The recommended immunohistochemical panel in this setting is currently under debate. In this study, we aimed to find a panel of immunohistochemical stains that would be helpful in determining the correct diagnosis in ambiguous uterine smooth muscle tumors, with an emphasis on investigating the possible usefulness of the WT1 antibody. Uterine leiomyomas were found to be immunoreactive with WT1. Since a previous study reported on the lack of immunoreactivity of uterine leiomyosarcomas with WT1, we speculated that WT1 might be useful in this setting. We retrospectively reviewed the medical charts and slides of 91 patients: 22 with leiomyosarcoma, 15 with smooth muscle tumor of uncertain malignant potential, and 54 with leiomyoma. Immunohistochemical stains for WT1, p16, p53, and Ki67 were performed on each case. We found that immunoreactivity with p16 and Ki67 (>40% and >10% of the tumor cells, respectively) and loss of nuclear expression of WT1 (<10% of the tumor cells) were significantly more common in leiomyosarcomas (all P<0.001). Mutated p53 immunohistochemical staining pattern was significantly more prevalent in leiomyosarcomas than in leiomyomas (P<0.001). Thus, in diagnostically challenging uterine smooth muscle tumors, we recommend using an immunohistochemical panel composed of Ki67, p16, p53, and WT1. A positive result in either of the former 2 (p16 >40% and/or Ki67 >10%) has the strongest association with leiomyosarcoma (sensitivity: 95.5%, specificity=88.9%, positive predictive value=77.8%, negative predictive value=98.0%).

Genomic and Epigenomic Profile of Uterine Smooth Muscle Tumors of Uncertain Malignant Potential (STUMPs) Revealed Similarities and Differences with Leiomyomas and Leiomyosarcomas

Uterine smooth muscle tumors of uncertain malignant potential (STUMPs) represent a heterogeneous group of tumors that cannot be histologically diagnosed as unequivocally benign or malignant. For this reason, many authors are working to obtain a better definition of diagnostic and prognostic criteria. In this work, we analyzed the genomic and epigenomic profile of uterine smooth muscle tumors (USMTs) in order to find similarities and differences between STUMPs, leiomyosarcomas (LMSs) and leiomyomas (LMs), and possibly identify prognostic factors in this group of tumors. Array-CGH data on 23 USMTs demonstrated the presence of a more similar genomic profile between STUMPs and LMSs. Some genes, such as PRKDC and PUM2, with a potential prognostic value, were never previously associated with STUMP. The methylation data appears to be very promising, especially with regards to the divergent profile found in the sample that relapsed, characterized by an overall CGI hypomethylation. Finally, the Gene Ontology analysis highlighted some cancer genes that could play a pivotal role in the unexpected aggressive behavior that can be found in some of these tumors. These genes could prove to be prognostic markers in the future.

Neck subcutaneous nodule as first metastasis from broad ligament leiomyosarcoma: a case report and review of literature

Background

Leiomyosarcoma usually develops in the myometrium and is characterized by a high recurrence rate, frequent hematogenous dissemination, and poor prognosis. Metastasis is usually to lungs, liver, and bone, and occasionally to the brain, but seldom to the head and neck region. Primary leiomyosarcoma very rarely arises in the broad ligament.

Case presentation

A 54-year old woman presented to the otolaryngology department with a mass in the right posterior region of the neck 4 years after surgery for a primary leiomyosarcoma of the right broad ligament. The neck mass was removed and found to be a metastatic leiomyosarcoma. Leiomyosarcoma localizations in lungs and liver were absent. Morphological examination showed both the primary and the secondary leiomyosarcomas to have features of low-grade tumors. One year after excision of the neck mass, the patient presented with tachycardia. Echocardiography detected two intracardiac nodules suggestive of metastatic tumors. Chemotherapy was administered; the disease has been stable since then.

Conclusions

We report the first case of broad ligament leiomyosarcoma with the neck subcutaneous region being the first site of secondary involvement. We speculate that the Batson venous plexus might have been the pathway of dissemination.

Tumor-like tricuspid myxomatus degeneration with a primary cardiac leiomyoma: A rare case report

We present an unusual case of a 47-year-old male with a cardiac mass arising from the tricuspid valve, which was misdiagnosed as a cystic myxoma. The patient received successful resection of the pathological tissue and tricuspid valvuloplasty. The mass turned out to be tricuspid cystic myxomatus degeneration with a primary cardiac leiomyoma finally. There was no recurrence after complete resection and tricuspid valvuloplasty by 1-year follow-up. To our best of our knowledge, only several cases of primary cardiac leiomyoma have been reported, and this is the first case of primary cardiac leiomyoma involving the tricuspid valve in an adult man. The present case suggests that the tricuspid valve should be another rare site of primary cardiac leiomyoma.

Giant uterine mass with uterine smooth muscle tumor of uncertain malignant potential: A case report

•

STUMP is a rare disease histologically, and giant STUMP is extremely rare.

•

To our knowledge, present case represents the largest STUMP reported.

•

After successful surgery, the patient is alive without evidence of recurrence.

Background

Uterine smooth muscle tumor of uncertain malignant potential (STUMP) is a rare tumor belonging to a group of smooth muscle tumors that possess both benign and malignant features, complicating the diagnosis.

Case report.

We present the case of a 41-year-old primiparous woman who complained of heavy menstrual bleeding and severe pressure symptoms in the lower abdomen for 3 months. Magnetic resonance imaging revealed a large intramural myoma measuring 35 × 25 cm in the lower uterine corpus. A laparotomy including total hysterectomy was performed. Grossly, the uterine mass measured 38.5 × 35.4 × 20.4 cm in the largest diameter and weighed 18.3 kg. Pathological analysis revealed a uterine mass diagnosed as a smooth muscle tumor of uncertain malignant potential. The patient was normally discharged 7 days after surgery and decided to follow up without further treatment. At the time of this report, the patient had been followed up as an outpatient for 18 months without recurrence.

Conclusion

Giant uterine STUMP is extremely rare and difficult to diagnose on physical examination and imaging findings alone. It is important to consider the possibility of an underlying malignancy when performing a preoperative examination and to perform frozen biopsy if malignancy is suspected. During follow-up, patients should undergo consultation with a gynecologic oncologist and should be surveilled closely because of the possibility of recurrence or metastasis.

Multimodality Imaging of Abdominopelvic Tumors with Venous Invasion

A broad range of abdominal and pelvic tumors can manifest with or develop intraluminal venous invasion. Imaging features at cross-sectional modalities and contrast-enhanced US that allow differentiation of tumor extension within veins from bland thrombus include the expansile nature of tumor thrombus and attenuation and enhancement similar to those of the primary tumor. Venous invasion is a distinctive feature of hepatocellular carcinoma and renal cell carcinoma with known prognostic and treatment implications; however, this finding remains an underrecognized characteristic of multiple other malignancies-including cholangiocarcinoma, adrenocortical carcinoma, pancreatic neuroendocrine tumor, and primary venous leiomyosarcoma-and can be a feature of benign tumors such as renal angiomyolipoma and uterine leiomyomatosis. Recognition of tumor venous invasion at imaging has clinical significance and management implications for a range of abdominal and pelvic tumors. For example, portal vein invasion is a strong negative prognostic indicator in patients with hepatocellular carcinoma. In patients with rectal cancer, diagnosis of extramural venous invasion helps predict local and distant recurrence and is associated with worse survival. The authors present venous invasion by vascular distribution and organ of primary tumor origin with review of typical imaging features. Common pitfalls and mimics of neoplastic thrombus, including artifacts and anatomic variants, are described to help differentiate these findings from tumor in vein. By accurately diagnosing tumor venous invasion, especially in tumors where its presence may not be a typical feature, radiologists can help referring clinicians develop the best treatment strategies for their patients. ^©RSNA, 2020.

Molecular and clinicopathologic characterization of intravenous leiomyomatosis

Intravenous leiomyomatosis (IVL) is an unusual uterine smooth muscle proliferation that can be associated with aggressive clinical behavior despite a histologically benign appearance. It has some overlapping molecular characteristics with both uterine leiomyoma and leiomyosarcoma based on limited genetic data. In this study, we assessed the clinical and morphological characteristics of 28 IVL and their correlation with molecular features and protein expression, using array comparative genomic hybridization (aCGH) and Cyclin D1, p16, phosphorylated-Rb, SMARCB1, SOX10, CAIX, SDHB and FH immunohistochemistry. The most common morphologies were cellular (n = 15), usual (n = 11), and vascular (n = 5; including 3 cellular IVL showing both vascular and cellular features). Among the immunohistochemical findings, the most striking was that all IVL showed differential expression of either p16 or Cyclin D1 in comparison to surrounding nonneoplastic tissue. Cytoplasmic phosphorylated-Rb was present in all but one IVL with hyalinization. SMARCB1, FH, and SDHB were retained; S0X10 and CAIX were not expressed. The most common genetic alterations involved 1p (39%), 22q (36%), 2q (29%), 1q (25%), 13q (21%), and 14q (21%). Hierarchical clustering analysis of recurrent aberrations revealed three molecular groups: Groups 1 (29%) and 2 (18%) with associated del(22q), and Group 3 (18%) with del(10q). The remaining IVL had nonspecific or no alterations by aCGH. Genomic index scores were calculated for all cases and showed no significant difference between the 14 IVL associated with aggressive clinical behavior (extrauterine extension or recurrence) and those without (median scores 5.15 vs 3.5). Among the 5 IVL associated with recurrence, 4 had a vascular morphology and 3 had alterations of 8q. Recurrent chromosome alterations detected herein overlap with those observed in the spectrum of uterine smooth muscle tumors and involve genes implicated in mesenchymal tumors at different sites with distinct morphological features.

Morphologic Variants of Pancreatic Neuroendocrine Tumors: Clinicopathologic Analysis and Prognostic Stratification

Better prognostication/stratification of pancreatic neuroendocrine tumors (PanNETs) is needed. In this detailed morpheomic study of 163 resected PanNETs, 11 unusual variants, some of which were not previously recognized, and others scarcely documented in the literature, were identified, and their pathologic characteristics were further analyzed. By behavior and clinicopathologic associations, these variants could be grouped into three prognostically different categories. I. More aggressive (20%). Included in this group were the variants that in average showed higher grade and stage and adverse outcome including oncocytic, plasmacytoid, lipid-rich and previously unrecognized hepatoid variants, which often had a more diffuse/broad-band growth pattern, with some also displaying discohesiveness. They were characterized by abundant cytoplasm and often had prominent nucleoli (as seen in metabolically active cells), thus the provisional name "metabolic cell phenotype." Because of their diversion from classical neuroendocrine cytomorphology, these variants created challenges on original diagnostic workup, particularly hepatoid examples, which revealed Arginase 1/Hep Par-1 expression in 50%. II. Less aggressive (10%). These cases either showed signs of maturation, including nested growth, paraganglioid pattern (which was previously unrecognized), and organoid PanNETs such as "ductulo-insular" growth, or showed symplastic/degenerative changes, and despite their paradoxically disconcerting histology, were more benevolent in behavior. III. Undetermined. There were other variants including mammary tubulolobular-like, pseudoglandular, peliotic, and sclerotic PanNETs, which although diagnostically challenging, their biologic significance could not be determined because of rarity or heterogeneous characteristics. Prognostic associations: Features that were significantly different in the more aggressive group than the less aggressive group were median size (5.0 vs 1.6 cm, p < 0.001), percentage of pT3+T4 cases (72% vs 12%, p < 0.001), Ki67 index (5.3% vs 2.3%, p = 0.001), % G2 and G3 cases (77% vs 27%, p < 0.001), and rate of lymph node and distant metastasis (96% vs 27%, p < 0.001). In stepwise logistic regression model using the 3 established prognosticators of T stage, size, and grade along with morphology, only aggressive-morphology (metabolic cell phenotype) was found to be associated with metastatic behavior with an odds ratio of 5.9 with 95% confidence interval (C.I.) 1.688 to 22.945 and p value 0.007. In conclusion, PanNETs display various morphologic patterns that are not only challenging and important diagnostically but appear to have biologic significance. Tumors with more diffuse growth of cells with nucleoli and abundant cytoplasm and/or discohesion (oncocytic, hepatoid, lipid-rich, plasmacytoid PanNETs), provisionally termed "metabolic cell phenotype," show aggressive characteristics and are an independent determinant of adverse outcome and thus may require closer post-surgical follow-up, whereas variants with more degenerative or mature features (ductuloinsular, pleomorphic, paraganglioma-like) appear to be more benevolent despite their more atypical and worrisome morphology.

Uterine smooth muscle tumours of uncertain malignant potential: single-centre experience and review of the literature

Introduction

Uterine smooth muscle tumours of uncertain malignant potential (STUMPs) are a rare histologically heterogeneous group of uterine smooth muscle tumours (SMTs). Their malignant potential and clinical differentiation between leiomyoma and leiomyosarcoma remain uncertain prior to surgical removal.

Aim of the study

To investigate the patients and tumour characteristics of patients with STUMPs and to propose algorithms for optimal diagnosis, treatment, and follow-up management.

Material and methods

This was a single-centre retrospective cohort study of all patients who underwent surgery for a preoperative diagnosis of uterine myoma at the University Hospital “Dr. Georgi Stranski”, Pleven, Bulgaria during a period of 33 months (from January 2013 until October 2015). Data were obtained from the medical history records. We performed descriptive analysis to characterise the patient population (e.g. demographics, age, contraceptive use, and complaints that led to the diagnosis) and the tumour characteristics. Last data were obtained prior May 2019.

Results

A total of 320 medical records were retrospectively evaluated. The preoperative diagnosis of myoma was confirmed in 279 of the cases (89.4%). In 27 (8.3%) cases the final histological result was completely different. In 14 (2.3%) a histological postoperative diagnosis of STUMP was identified. All 14 STUMP lesions were intramural with a median size of 7.5 cm (range 3.5 to 15 cm). The median age at diagnosis of STUMP was 45.4 years (range 36 to 52 years), and 92.9% (n = 13) of the patients were premenopausal. Ultrasound data of a rapidly growing myoma were a reason for diagnosis in only three patients (25%), whereas 92.9% of the patients (n = 13) presented with heavy menstrual bleeding with or without anaemia. After surgery, none of the patients with STUMP experienced a relapse of the disease within the median follow-up time of 48 months (R = 40-78).

Conclusions

STUMP tumours are rare tumours, predominantly diagnosed in premenopausal women. They define a group of patients with very good long-term prognosis. Therefore, longer follow-up is needed to allow for conclusions on recurrence rate and survival.

Oncologic and Reproductive Outcomes of Uterine Smooth Muscle Tumor of Uncertain Malignant Potential: A Single Center Retrospective Study of 67 Cases

Background: The term “uterine smooth muscle tumor of uncertain malignant potential” (STUMP) indicates a rare tumor that cannot be classified as a benign leiomyoma or malignant leiomyosarcoma. In this study, we assessed the clinical characteristics, fertility, and oncologic outcomes of patients diagnosed as STUMP in 14 years. In addition, we analyzed the risk factors for recurrence in patients with STUMP.

Methods: Medical records of STUMP patients at Peking Union Medical College Hospital (PUMCH) between January 2005 and June 2019 were reviewed and analyzed. Disease-free survival, age of diagnosis, tumor size, surgical procedure, pathology and immunohistochemistry, clinical characteristics, recurrence rate, and reproductive outcomes in the follow-up period were assessed. Univariate and multivariate analyses were performed to determine the prognostic factors.

Results: The median age was 42 years old (range: 21–63). Total hysterectomy with or without bilateral salpingo-oophorectomy was performed in 29/67 cases (43.3%), and myomectomy was performed in 38/67 cases (56.7%). Ten patients experienced recurrences, and all but two recurrences occurred within 5 years after the initial surgery. Only two of these recurrences were leiomyosarcoma. There were no deaths in the median follow-up period of 48.4 (range 2.6–170.2) months. There were no remarkable differences in location of tumor between the myomectomy and hysterectomy groups, but the patients in the myomectomy group were younger than those in the hysterectomy group. In univariate and multivariate analysis, mitosis on pathology was the only independent risk factor for recurrence. Expression of Ki-67, p53, and p16 was significantly higher in patients with recurrence. Seven of the 35 patients who attempted to conceive had successful pregnancies.

Conclusions: The prognosis of STUMP was favorable and tumors with more than 10 mitoses per 10 high power field should be monitored closely. The surgical procedure was not an independent risk factor of recurrence, and myomectomy may be an acceptable option for patients wishing to preserve fertility.

Clinical experience of uterine smooth muscle tumor of uncertain malignant potential in two gynecological centers: Oncological and obstetrical aspects

OBJECTIVES

To evaluate the clinical characteristics and obstetrical and oncological outcomes of patients with uterine smooth muscle tumors of uncertain malignant potential (STUMP) and analyze the risk factors for recurrence.

STUDY DESIGN

A retrospective cohort study was performed at two gynecological centers using data collected between January 2008 and August 2018. All the patients enrolled were diagnosed with STUMP and had been followed up for at least 6 months. The patients' characteristics, treatment methods, recurrence rate, and subsequent pregnancy outcomes were evaluated.

RESULTS

The mean age of the 62 patients was 36.1 ± 9.1 years (median 35, range 20-55 years) and mean follow-up duration was 36.3 ± 26.8 months (29.5, 6-130). All the patients were of premenopausal status. Fourteen patients (22.6 %) were initially treated by hysterectomy and 48 (77.4 %) by myomectomy. During the study period, three patients (4.8 %) experienced recurrence. However, there was no statistical difference between myomectomy and hysterectomy in terms of the rate of recurrence of STUMP or sarcoma, and all patients survived even after recurrence. Multivariate analysis revealed that a history of previous myomectomy was the sole independent risk factor for recurrence (odds ratio = 51.071; 95 % confidence interval = 2.743-950.726; p = 0.008). Subsequent pregnancies were successful in 10 of 19 women (52.6 %) who tried to conceive. Two of them had ongoing pregnancies at the time of last follow-up; the remaining eight women experienced a total of 14 subsequent pregnancies.

CONCLUSIONS

The recurrence rate of STUMP was similar between hysterectomy and myomectomy. Therefore, fertility sparing myomectomy can be considered in women diagnosed with STUMP with close monitoring.

EP4 and Class III β-Tubulin Expression in Uterine Smooth Muscle Tumors: Implications for Prognosis and Treatment

The microtubule-stabilizing agent docetaxel in combination with gemcitabine represents one of the most effective regimens against the aggressive gynecologic tumor leiomyosarcoma (LMS). Upregulation of class III β-tubulin has previously been shown to confer taxane resistance in a variety of human cancers. Prostaglandin E₂ receptor EP4 is linked to progression of a variety of human cancers and may represent a novel target for tumor inhibition in LMS. We evaluated the hypotheses that EP4 and class III β-tubulin have increased expression in LMS in comparison to normal myometrium or benign tumors and that expression of class III β-tubulin correlates with resistance to taxanes and poor clinical outcome. Gene expression was examined using TCGA data and correlated with clinicopathologic outcome which demonstrated that class III β-tubulin is more highly expressed in more aggressive sarcomas with EP4 being widely expressed in all subtypes of sarcoma. Immunohistochemistry for EP4 and class III β-tubulin was performed on patients with LMS, leiomyomatosis/STUMP, leiomyoma, and normal myometrium. Expression of EP4 and class III β-tubulin were characterized for cell lines SK-UT-1, SK-UT-1B, and PHM-41 and these cell lines were treated with docetaxel alone and in combination with EP4 inhibitors. In taxane-resistant cell lines that overexpress class III β-tubulin and EP4, treatment with EP4 inhibitor resulted in at least 2-fold sensitization to docetaxel. Expression of class III β-tubulin and EP4 in LMS may identify patients at risk of resistance to standard chemotherapies and candidates for augmentation of therapy through EP4 inhibition.

Uterine smooth muscle tumors of unknown malignant potential: A challenging question

Uterine smooth muscle tumors of unknown malignant potential [STUMP]s are neoplasms with pathological features that preclude an equivocal diagnosis of leiomyosarcoma, but that do not fulfill the criteria for leiomyoma or its variants, and raise concerns that the tumors may behave in a malign fashion. Total hysterectomy with or without bilateral salpingo-oophorectomy is the standard treatment if fertility is completed, whereas myomectomy alone can be taken into consideration in young patients who desire to preserve childbearing potential. A careful surveillance every 6 months for 5 years and then yearly is strongly warranted. Patients with STUMP can relapse as either STUMP or leiomyosarcoma in approximately 11-13% of the cases, and their 5-year overall survival ranges from 92 to 100%. The present paper reviews the clinicopathological features of uterine STUMPs with a particular focus on most commonly accepted histopathological criteria for the diagnosis and on biological behaviour of these controversial neoplasms.

Secondary Leiomyosarcoma of the Lower Limb Following Uterine Smooth Muscle Tumor of Uncertain Malignant Potential

Introduction:

This report presents uterine smooth muscle tumors of uncertain malignant potential course with an unpredictable clinical behavior and late metastases. Metastases have been described to the humerus, lung, and peritoneum.

Case Presentation:

Hereby we present the case of a 71-year-old woman with a past surgical history of hysterectomy and bilateral adnexectomy due to a smooth muscle tumor of unknown malignant potential, who was evaluated 6 years later after the appearance of a mass in the proximal third of the right lower limb. The mass was diagnosed as a G1 epithelioid leiomyosarcoma and was surgically removed with immediate reconstruction with a tendinous transfer to the tibialis posterior muscle to maintain foot dorsiflexion.

Conclusion:

Patients diagnosed with smooth uterine muscle tumors of uncertain malignant potential should be closely followed up given the possibility of recurrence and late metastases, bearing in mind uncommon locations as well, such as the lower limb.