Immunohistochemical Analysis of P16, P53, and Ki-67 Expression in Uterine Smooth Muscle Tumors:

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.

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.

Raf kinase inhibitor protein expression in smooth muscle tumours of the uterus: a diagnostic marker for leiomyosarcoma?

RESEARCH QUESTION

What is the expression pattern of Raf kinase inhibitory protein (RKIP) in different subtypes of leiomyoma (usual type, cellular, apoplectic or haemorrhagic leiomyoma, leiomyoma with bizarre nuclei and lipoleiomyoma) and leiomyosarcoma specimens, and what is its biological role in leiomyosarcoma cells?

DESIGN

Leiomyoma and leiomyosarcoma specimens underwent immunohistochemistry staining. Leiomyosarcoma SK-LMS-1 cell line was RKIP knocked down and RKIP overexpressed, and cell viability, wound healing migration and clonogenicity assays were carried out.

RESULTS

A higher immunohistochemical expression of RKIP was observed in bizarre leiomyomas, than in usual-type leiomyomas. Decreased expression was also found in cellular leiomyoma, with generally absent staining in leiomyosarcomas. Upon RKIP expression manipulation in SK-LMS-1 cell line, no major differences were observed in cell viability and migration capacity over time. RKIP knockout, however, resulted in a significant increase in the cell's ability to form colonies (P = 0.011).

CONCLUSION

RKIP distinct expression pattern among leiomyoma histotype and leiomyosarcoma, and its effect on leiomyosarcoma cells on colony formation, encourages further studies of RKIP in uterine smooth muscle disorders.

Molecular-Based Immunohistochemical Algorithm for Uterine Leiomyosarcoma Diagnosis

The morphologic assessment of uterine leiomyosarcoma (LMS) may be challenging, and diagnostic immunohistochemical (IHC) analysis is currently lacking. We evaluated the genomic landscape of 167 uterine LMS by targeted next-generation sequencing (NGS) to identify common genomic alterations. IHC analyses corresponding to these genomic landmarks were applied to a test cohort of 16 uterine LMS, 6 smooth muscle tumors of uncertain malignant potential (STUMP), and 6 leiomyomas with NGS data and a validation cohort of 8 uterine LMS, 12 STUMP, 21 leiomyomas and leiomyoma variants, 7 low-grade endometrial stromal sarcomas, and 2 diagnostically challenging uterine smooth muscle tumors. IHC results were individually interpreted by 3 pathologists blinded to NGS data. Overall, 94% of LMS showed ≥1 genomic alteration involving TP53, RB1, ATRX, PTEN, CDKN2A, or MDM2, with 80% showing alterations in ≥2 of these genes. In the test cohort, an initial panel of p53, Rb, PTEN, and ATRX was applied, followed by a panel of DAXX, MTAP, and MDM2 in cases without abnormalities. Abnormal p53, Rb, PTEN, and ATRX IHC expression was seen in 75%, 88%, 44%, and 38% of LMS, respectively, in the test cohort. Two or more abnormal IHC results among these markers were seen in 81% of LMS. STUMPs demonstrated only 1 IHC abnormality involving these markers. No IHC abnormalities were seen in leiomyomas. In the validation cohort, abnormal p53, Rb, and PTEN IHC results were seen in LMS, whereas rare STUMP or leiomyomas with bizarre nuclei showed IHC abnormalities involving only 1 of the markers. Abnormalities in ≥2 markers were present in both diagnostically challenging smooth muscle tumors, confirming LMS. Concordance was excellent among pathologists in the interpretation of IHC (κ = 0.97) and between IHC and NGS results (κ = 0.941). Uterine LMS exhibit genomic landmark alterations for which IHC surrogates exist, and a diagnostic algorithm involving molecular-based IHC may aid in the evaluation of unusual uterine smooth muscle tumors.

Leiomyoma with Bizarre Nuclei: A Current Update

Leiomyoma with bizarre nuclei (LBN), also known as symplastic leiomyoma, is a histological subtype of benign leiomyoma with bizarre cells and nuclear atypia. Differentiating LBN from other benign leiomyoma subtypes, uterine smooth muscle tumors of uncertain malignant potential (STUMP), or leiomyosarcoma (LMS) can be diagnostically challenging owing to overlapping features in clinical presentation and pathologic morphological analysis. The difficulty of distinguishing LBN from other lesions, especially from LMS, and the potential of LBN for subsequent malignant transformation make LBN an important topic of research. Herein, we review the definition, diagnosis, treatment, and prognosis of LBN. Histopathological examination is essential for distinguishing LBN from other diseases. Pathology sampling and morphological examination remain the key to diagnosis. The newly established ancillary immunohistochemical (IHC) and molecular genetic analysis can be useful tools for differential diagnosis. Furthermore, serum biomarkers and imaging examination may also be useful diagnostic tools. Attention should be paid to the differentiation between LBN and LMS because morphological diagnosis may still be challenging in some cases. Some IHC markers of LBN have been identified, which may be helpful for differential diagnosis. Furthermore, the use of IHC panels as diagnostic markers may be advocated. Molecular genetic studies suggest that some genes can aid with the differential diagnosis between LBN and LMS. However, increasing evidence support the idea that LBN and LMS are molecularly related, indicating that LBN may represent a potentially malignant stage of precancerous progression. At present, conservative treatment is recommended for primary LBN, especially for patients desiring to retain fertility, but close follow-up with imaging examinations is required.

Epigenetic Features in Uterine Leiomyosarcoma and Endometrial Stromal Sarcomas: An Overview of the Literature

There is a consensus that epigenetic alterations play a key role in cancer initiation and its biology. Studies evaluating the modification in the DNA methylation and chromatin remodeling patterns, as well as gene regulation profile by non-coding RNAs (ncRNAs) have led to the development of novel therapeutic approaches to treat several tumor types. Indeed, despite clinical and translational challenges, combinatorial therapies employing agents targeting epigenetic modifications with conventional approaches have shown encouraging results. However, for rare neoplasia such as uterine leiomyosarcomas (LMS) and endometrial stromal sarcomas (ESS), treatment options are still limited. LMS has high chromosomal instability and molecular derangements, while ESS can present a specific gene fusion signature. Although they are the most frequent types of "pure" uterine sarcomas, these tumors are difficult to diagnose, have high rates of recurrence, and frequently develop resistance to current treatment options. The challenges involving the management of these tumors arise from the fact that the molecular mechanisms governing their progression have not been entirely elucidated. Hence, to fill this gap and highlight the importance of ongoing and future studies, we have cross-referenced the literature on uterine LMS and ESS and compiled the most relevant epigenetic studies, published between 2009 and 2022.

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.

Interrogating the Genomic Landscape of Uterine Leiomyosarcoma: A Potential for Patient Benefit

Uterine leiomyosarcoma (uLMS) is a rare and aggressive gynaecological malignancy. Surgical removal and chemotherapy are commonly used to treat uLMS, but recurrence rates are high. Over the last few decades, clarification of the genomic landscape of uLMS has revealed a number of recurring mutations, including TP53, RB1, ATRX, PTEN, and MED12. Such genomic aberrations are difficult to target therapeutically or are actively targeted in other malignancies, and their potential as targets for the treatment of uLMS remains largely unexplored. Recent identification of deficiencies in homologous recombination in a minority of these tumours, however, has provided a rationale for investigation of PARP inhibitors in this sub-set. Here, we review these mutations and the evidence for therapeutic avenues that may be applied in uLMS. We also provide a comprehensive background on diagnosis and current therapeutic strategies as well as reviewing preclinical models of uLMS, which may be employed not only in testing emerging therapies but also in understanding this challenging and deadly disease.

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.

Uterine smooth muscle tumors of uncertain malignant potential (STUMP): A retrospective study in a single center

OBJECTIVE

Uterine smooth muscle tumors of uncertain malignant potential (STUMP) is a heterogeneous group of tumors with histological and biological diversity that cannot be defined as a benign leiomyoma or malignant leiomyosarcoma. The study aims to investigate the diagnostic methods, treatment management and prognosis of STUMP patients in a 13-year period.

STUDY DESIGN

We retrospectively reviewed the clinicopathologic information of 31 STUMP patients in Peking University People's Hospital. Statistical analyses were conducted to compare the difference of clinical characteristics between the women in myomectomy group and those in hysterectomy group.

RESULTS

The most common clinical presentation was menstrual disorder. The tumors were mainly manifested as hypoechoic, non-cystic nodules with low blood flow signal by pelvic doppler ultrasonography. Most tumors carried Ki-67 index ranging from 10% to 30%. Immunohistochemical markers such as ER, PR, p16 and Desmin was positively expressed in tumors. At the first operation, 21 cases underwent myomectomy and 10 cases underwent hysterectomy. The patients in myomectomy group were younger than those in hysterectomy group. In the follow-up period, two cases experienced a relapse in the form of STUMP within 36 months. One case died of cardiovascular accident while the other cases were alive. Six of 21 women in myomectomy group desired pregnancy and two healthy live births were recorded.

CONCLUSION

The diagnosis of STUMP primarily depends on histopathologic features. Fertility-sparing surgery may be a treatment selection for patients with fertility desire. Patients with STUMP, especially in the case of myomectomy, should be informed of recurrence risk and monitored closely.

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%).

Digital Quantification of Ki-67 and PHH3 in the Classification of Uterine Smooth Muscle Tumors

Uterine smooth muscle tumors are the most common tumors of the female genital tract and include leiomyoma (LM) and its variants, smooth muscle tumors of uncertain malignant potential (STUMP), and leiomyosarcoma (LMS). Accurate diagnosis of LMS is determined by nuclear atypia, mitotic count, and the presence or absence of tumor cell necrosis, a process which is often difficult and subjective. In this study, we correlated digital quantification of proliferation marker Ki-67 and mitotic marker phosphohistone H3 (PHH3) to mitotic count, classification of uterine smooth muscle tumors, and clinical outcomes. A total of 39 cases (17 LMS, 5 STUMP, 10 LM with bizarre nuclei, and 7 LM) were included. Mitotic count, Ki-67, and PHH3 were significantly correlated. When comparing the LMS group to the STUMP, LM with bizarre nuclei, and LM groups combined, LMS showed a significantly greater digital quantification of Ki-67 (median 10.6% vs. 0.4%, P<0.001) and PHH3 (median 0.5% vs. 0.14%, P=0.022). Ki-67 was a better predictor of LMS compared with PHH3 (area under the curve 0.92 vs. 0.73, P=0.017). Above a threshold Ki-67 value of 3.8%, the sensitivity was 82% and specificity was 91%. Clinical outcomes were available for 10 patients (8 LMS and 2 STUMP), and inferior progression-free survival was noted for patients with higher Ki-67 values. Overall, this study suggests that digital quantification of Ki-67 can potentially aid in diagnosis of LMS.

Undifferentiated and dedifferentiated neoplasms of the female genital tract

Undifferentiated neoplasms in the female gynecologic tract comprise two main groups-undifferentiated carcinoma, most common in the endometrium and ovary, and undifferentiated uterine sarcoma, although tumors with an undifferentiated appearance may occur in all gynecologic organs. Their differential diagnosis is broad and generous sampling, careful morphological evaluation, judicious use of immunohistochemistry, and in many cases, molecular testing is often essential in the diagnostic work-up. As some of these neoplasms fail to respond to conventional chemotherapy regimens and/or radiation therapy, targeted therapy may be valuable in treating these highly aggressive tumors, thus the importance of precise diagnosis. In this review we discuss the clinicopathological features of undifferentiated carcinoma, dedifferentiated carcinoma, and undifferentiated uterine sarcoma, followed by a comprehensive analysis of morphological mimickers. Finally, we briefly review ovarian and lower genital tract tumors with an undifferentiated histological appearance.

Exosomal long non-coding RNA UCA1 functions as growth inhibitor in esophageal cancer

PURPOSE

Esophageal cancer is a highly lethal and broad-spreading malignant tumor worldwide. Exosome-carrying lncRNAs play an essential role in the pathogenesis of various cancers.

RESULTS

The results revealed that the expression of UCA1 was decreased in esophageal cancer tissues and plasma exosomes. UCA1 was enriched in exosomes, and exosomal UCA1 was a promising biomarker for the diagnosis of esophageal cancer with 86.7% sensitivity and 70.2% specificity. Overexpression of UCA1 played anticancer roles in esophageal cancer cells through inhibiting cell proliferation, invasion and migration, and colony formation. Also, exosomal UCA1 was taken up by esophageal cancer cells and inhibited the progression of esophageal cancer in vitro and tumor growth in vivo. Furthermore, exosomal UCA1 could directly target miRNA-613 in esophageal cancer cells.

CONCLUSIONS

The results suggested that exosomal UCA1 inhibits tumorigenesis and progression of esophageal cancer in vitro and in vivo, and might be a promising biomarker for esophageal cancer.

PATIENT AND METHODS

In this study, we determined the expression of UCA1 in esophageal cancer tissues, plasma exosomes of patients with esophageal cancer. We determined the potential of exosomal UCA1 as a biomarker and its effect on the pathogenesis and progression of esophageal cancer in vitro and in vivo.

Italian consensus conference on management of uterine sarcomas on behalf of S.I.G.O. (Societa' italiana di Ginecologia E Ostetricia)

BACKGROUND

Uterine sarcomas are very rare tumours with different histotypes, molecular features and clinical outcomes; therefore, it is difficult to carry out prospective clinical trials, and this often results in heterogeneous management of patients in the clinical practice.

AIM

We planned to set up an Italian consensus conference on these diseases in order to provide recommendations on treatments and quality of care in our country.

RESULTS

Early-stage uterine sarcomas are managed by hysterectomy + bilateral salpingo-oophorectomy according to menopausal status and histology; lymphadenectomy is not indicated in patients without bulky nodes, and morcellation must be avoided. The postoperative management is represented by observation, even though chemotherapy can be considered in some high-risk patients. In early-stage low-grade endometrial stromal sarcoma and adenosarcomas without sarcomatous overgrowth, hormonal adjuvant treatment can be offered based on hormone receptor expression. In selected cases, external beam radiotherapy ± brachytherapy can be considered to increase local control only. Patients with advanced disease involving the abdomen can be offered primary chemotherapy (or hormonal therapy in the case of low-grade endometrial stromal sarcoma and adenosarcoma without sarcomatous overgrowth), even if potentially resectable in the absence of residual disease in order to test the chemosensitivity (or hormonosensitivity); debulking surgery can be considered in patients with clinical and radiological response. Chemotherapy is based on anthracyclines ± ifosfamide or dacarbazine. Palliative radiotherapy can be offered for symptom control, and stereotactic radiotherapy can be used for up to five isolated metastatic lesions.

CONCLUSIONS

Treatment of uterine sarcoma should be centralised at referral centres and managed in a multidisciplinary setting.

Molecular differential diagnosis of uterine leiomyomas and leiomyosarcomas

Uterine leiomyomas (LM) and leiomyosarcomas (LMS) are considered biologically unrelated tumors due to their cytogenetic and molecular disparity. Yet, these tumors share morphological and molecular characteristics that cannot be differentiated through current clinical diagnostic tests, and thus cannot be definitively classified as benign or malignant until surgery. Newer approaches are needed for the identification of these tumors, as has been done for other tissues. The application of next generation sequencing enables the detection of new mutations that, when coupled to machine learning bioinformatic tools, advances our understanding of chromosomal instability. These approaches in the context of LM and LMS could allow the discovery of genetic variants and possible genomic markers. Additionally, the potential clinical utility of circulating cell-free tumor DNA could revolutionize the noninvasive detection and monitoring of these tumors. Here, we seek to provide a perspective on the molecular background of LM and LMS, recognizing their distinct molecular features that may lead to improved diagnosis and personalized treatments, which would have a measurable impact on women's reproductive health.

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

OBJECTIVE(S)

Smooth muscle tumors of uncertain malignant potential are rare uterine neoplasms. Their identification through imaging is still limited due to the few available descriptions in the scientific literature. The objective of this paper is to provide clinical and ultrasound features that could support an early identification of these neoplasms.

STUDY DESIGN

We retrospectively evaluated preoperative sonographic data of patients receiving a histopathological diagnosis of smooth muscle tumors of uncertain malignant potential between 2014 and 2019 at the S. Anna Hospital (Turin, Italy), a tertiary gynecological center. Tumors were characterized on the basis of ultrasound images using terms and definitions according to the morphological uterus sonographic assessment group.

RESULTS

A total of fourteen patients with smooth muscle tumors of uncertain malignant potential (20 lesions, including 18 pure and 2 with associated leiomyosarcoma) were identified. The median age was 47 years (range 28-77) and nine (64%) patients were of reproductive age. Six patients (43%) were asymptomatic, two (14%) presented with abdominal pain, two (14 %) with menorrhagia and four (29%) with both symptoms. Two (14%) patients developed local recurrences as uterine smooth muscle tumor of uncertain malignant potential and leiomyosarcoma, respectively. At ultrasound imaging, nine (69%) smooth muscle tumors of uncertain malignant potential were poorly or moderately vascularized and nine (82%) showed both circumferential and intra-lesional flows. Only three (15%) showed shadowing. The outlines were well-defined in seventeen cases (85%) and most (90%) showed isoechoic or mixed echogenicity with microcystic anechoic areas in fourteen (70%) of cases.

CONCLUSION(S)

Sonographic features of smooth muscle tumors of uncertain malignant potential may vary and a pathognomonic description has not been recognized. However, the identification of single or multiple lesions with specific ultrasound features should raise the suspicion of tumors of uncertain malignant potential. These features include isoechogenicity or mixed echogenicity, regular borders, presence of internal microcystic and anechoic areas, circumferential and intralesional vascularization ranging from minimal to high and absence of shadowing.

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.

A Comprehensive Review of Biomarker Use in the Gynecologic Tract Including Differential Diagnoses and Diagnostic Pitfalls

Morphologic (ie, hematoxylin and eosin) evaluation of the Mullerian tract remains the gold standard for diagnostic evaluation; nevertheless, ancillary/biomarker studies are increasingly utilized in daily practice to assist in the subclassification of gynecologic lesions and tumors. The most frequently utilized "biomarker" technique is immunohistochemistry; however, in situ hybridization (chromogenic and fluorescence), chromosomal evaluation, and molecular analysis can also be utilized to aid in diagnosis. This review focuses on the use of immunohistochemistry in the Mullerian tract, and discusses common antibody panels, sensitivity and specificity of specific antibodies, and points out potential diagnostic pitfalls when using such antibodies.

Imaging in gynecological disease (15): clinical and ultrasound characteristics of uterine sarcoma

OBJECTIVE

To describe the clinical and ultrasound characteristics of uterine sarcomas.

METHODS

This was a retrospective multicenter study. From the databases of 13 ultrasound centers, we identified patients with a histological diagnosis of uterine sarcoma with available ultrasound reports and ultrasound images who had undergone preoperative ultrasound examination between 1996 and 2016. As the first step, each author collected information from the original ultrasound reports from his/her own center on predefined ultrasound features of the tumors and by reviewing the ultrasound images to identify information on variables not described in the original report. As the second step, 16 ultrasound examiners reviewed the images electronically in a consensus meeting and described them using predetermined terminology.

RESULTS

We identified 116 patients with leiomyosarcoma, 48 with endometrial stromal sarcoma and 31 with undifferentiated endometrial sarcoma. Median age of the patients was 56 years (range, 26-86 years). Most patients were symptomatic at diagnosis (164/183 (89.6%)), the most frequent presenting symptom being abnormal vaginal bleeding (91/183 (49.7%)). Patients with endometrial stromal sarcoma were younger than those with leiomyosarcoma and undifferentiated endometrial sarcoma (median age, 46 years vs 57 and 60 years, respectively). According to the assessment by the original ultrasound examiners, the median diameter of the largest tumor was 91 mm (range, 7-321 mm). Visible normal myometrium was reported in 149/195 (76.4%) cases, and 80.0% (156/195) of lesions were solitary. Most sarcomas (155/195 (79.5%)) were solid masses (> 80% solid tissue), and most manifested inhomogeneous echogenicity of the solid tissue (151/195 (77.4%)); one sarcoma was multilocular without solid components. Cystic areas were described in 87/195 (44.6%) tumors and most cyst cavities had irregular walls (67/87 (77.0%)). Internal shadowing was observed in 42/192 (21.9%) sarcomas and fan-shaped shadowing in 4/192 (2.1%). Moderate or rich vascularization was found on color-Doppler examination in 127/187 (67.9%) cases. In 153/195 (78.5%) sarcomas, the original ultrasound examiner suspected malignancy. Though there were some differences, the results of the first and second steps of the analysis were broadly similar.

CONCLUSIONS

Uterine sarcomas typically appear as solid masses with inhomogeneous echogenicity, sometimes with irregular cystic areas but only very occasionally with fan-shaped shadowing. Most are moderately or very well vascularized. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

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.

The Usefulness of Immunohistochemistry in the Differential Diagnosis of Lesions Originating from the Myometrium

Uterine leiomyomas (LMs), currently the most common gynecological complaint around the world, are a serious medical, social and economic problem. Accurate diagnosis is the necessary prerequisite of the diagnostic-therapeutic process. Statistically, mistakes may occur more often in case of disease entities with high prevalence rates. Histopathology, based on increasingly advanced immunohistochemistry methods, is routinely used in the diagnosis of neoplastic diseases. Markers of the highest sensitivity and specificity profiles are used in the process. As far as LMs are concerned, the crux of the matter is to identify patients with seemingly benign lesions which turn out to be suspicious (e.g., atypical LM) or malignant (e.g., leiomyosarcoma (LMS)), which is not uncommon. In this study, we present the current state of knowledge about the use of immunohistochemical markers in the differential diagnosis of LM, atypical LM, smooth muscle tumors of uncertain malignant potential (STUMP), and LMS, as well as their clinical predictive value.

Uterine sarcomas

Uterine sarcomas account for approximately 3%-7% of all uterine cancers. Since carcinosarcomas are currently classified as metaplastic carcinomas, leiomyosarcomas remain the most common subtype. Exclusion of several histologic variants of leiomyoma, as well as atypical smooth muscle tumors (so-called "smooth muscle tumors of uncertain malignant potential"), has highlighted that the vast majority of leiomyosarcomas are high-grade tumors associated with poor prognosis even when apparently confined to the uterus. Low-grade endometrial stromal sarcomas are indolent tumors associated with long-term survival. High-grade endometrial stromal sarcomas and undifferentiated endometrial sarcomas behave more aggressively than tumors showing nuclear uniformity. Adenosarcomas have a favorable prognosis except for tumors showing myometrial invasion or sarcomatous overgrowth. The prognosis for carcinosarcomas (which are considered here in a postscript fashion) is usually worse than that for grade 3 endometrial carcinomas. Tumor stage is the single most important prognostic factor for uterine sarcomas.

Endometrial Stromal Sarcoma of the Uterus: Magnetic Resonance Imaging Findings Including Apparent Diffusion Coefficient Value and Its Correlation With Ki-67 Expression

OBJECTIVE

This study aimed to investigate the conventional magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) features of endometrial stromal sarcoma (ESS) including a preliminary investigation of the correlation between the apparent diffusion coefficient (ADC) value and Ki-67 expression.

METHODS

The clinical and MRI data of 15 patients with ESS confirmed by surgery and pathology were analyzed retrospectively. The conventional MR morphological features, signal intensity on DWI, ADC value (n = 14), and clinicopathological marker Ki-67 (n = 13) were evaluated.

RESULTS

Of 15 patients with ESS, 13 tumors were low-grade ESS (LGESS), and the remaining 2 were high-grade ESS (HGESS); 9 tumors were located in the myometrium, 5 were located in the endometrium and/or cervical canal, and 1 was located in extrauterine. Thirteen (87%) of 15 tumors showed a homo- or heterogeneous isointensity on T1-weighted imaging and a heterogeneous hyperintensity on T2-weighted imaging. The hypointense bands were observed in 11 tumors (73%) on T2-weighted imaging. The degenerations (cystic/necrosis/hemorrhage) were observed in 7 LGESS tumors and 2 HGESS tumors. The DWI hyperintensity was observed in 13 tumors (93%) and isointensity in remaining 1. The mean ADC value of the solid components in 14 ESSs was (1.05 ± 0.20) × 10mm/s. The contrast-enhanced MRI showed an obvious enhancement in 14 tumors (93%) (heterogeneous in 7 LGESSs and 2 HGESSs; homogeneous in 5 LGESSs). The ADC value was inversely correlated with the Ki-67 expression (r = -0.613, P = 0.026).

CONCLUSIONS

Patients with ESS showed some characteristics on conventional MRI and DWI, and there was an inverse correlation between the ADC value and Ki-67 expression.

The selected biomarker analysis in 5 types of uterine smooth muscle tumors

Uterine smooth muscle tumors (USMTs) consist of a group of histologically heterogeneous and clinically diverse diseases ranging from malignant leiomyosarcoma (LMS) to benign leiomyoma (ULM). The genetic alterations in LMS are complex, with some genetic alterations present in both LMS and other atypical histologic variants of USMT. In this study, we reviewed 119 USMTs with a diagnosis of LMS, smooth muscle tumor of uncertain malignant potential, atypical leiomyomas/leiomyoma with bizarre nuclei, and cellular leiomyoma, as well as 46 ULMs and 60 myometrial controls. We selected 17 biomarkers highly relevant to LMS in 4 tumorigenic pathways including steroid hormone receptors (estrogen receptor [ER] and progesterone receptor [PR]), cell cycle/tumor suppressor genes, AKT pathway markers, and associated oncogenes. ER and PR expression was significantly lower in LMS than smooth muscle tumor of uncertain malignant potential, atypical leiomyomas/leiomyoma with bizarre nuclei, cellular leiomyoma, and ULM (P < .01). Sixty-five percent of LMSs showed complete loss of ER, and 75% of LMSs showed complete loss of PR. All cell cycle genes were differentially expressed in different types of tumor, but significant overlap was noted. More than 75% of LMSs had Ki-67 index greater than 33%, and only 5% in all other types of USMT. Expression of the selected oncogenes varied widely among different types of USMT. PR positivity and p53 had a borderline association with progression-free survival (P = .055 for PR and P = .0847 for p53). Furthermore, high PR expression was significantly associated with a longer overall survival (P = .0163, hazard ratio 0.198). Cell proliferative indices (Ki-67) and sex steroid hormone receptors were the most valuable markers in differentiating LMS from other USMT variants.

The Use of Smoothelin and Other Antibodies in the Diagnosis of Uterine and Soft Tissue Smooth Muscle Tumors

Smoothelin is a cytoplasmic protein expressed in differentiated smooth muscle cells. Immunohistochemical evaluation of smoothelin has previously been reported in gastrointestinal (GI) smooth muscle tumors, but has yet to be studied in smooth muscle tumors of uterine and other soft tissue origin. DOG1 expression is reported to be specific for GI stromal tumors; however, variable expression has been reported in leiomyosarcomas (LMS) depending on site of origin. Overexpression of p16 is common in LMS of uterine and other sites of origin, but has not been correlated with tumor grade. This study explores the differential expression of these markers, as well as caldesmon, in LMS cases to assess diagnostic utility. Using tissue microarrays and cases from Tulane Medical Center and Medical College of Wisconsin, expression of smoothelin, DOG1, caldesmon, and p16 was evaluated by immunohistochemistry in 87 cases of LMS. The cases were subdivided by location of origin into uterine (N=31) and nonuterine (N=56) with 10 of the nonuterine of GI origin, as well as by grade into low grade (N=27) and intermediate and high grade (N=60). Differential expression among different grades and locations was evaluated. The same markers were evaluated in atypical leiomyoma cases (N=4) and 1 smooth muscle tumor of uncertain malignant potential case (N=1). Smoothelin expression was also assessed in 20 benign uterine leiomyomas. Weak DOG1 expression is rare but possible in extrauterine LMS. Expression of p16 is common in both uterine and extrauterine LMS, and more frequent in higher grades. Expression of smoothelin in this study differed depending on tumor type, grade, and site of origin. All leiomyomas and most atypical leiomyomas showed cytoplasmic positivity for smoothelin, whereas only 5% of LMS had cytoplasmic expression. The study suggests smoothelin may be downregulated in the cytoplasm of malignant smooth muscle tumor cells and may serve as a supportive aid in the distinction of LMS from benign smooth muscle tumors in cases where it is difficult by morphology alone.

Diagnostic immunohistochemistry in gynaecological neoplasia: a brief survey of the most common scenarios

Immunohistochemistry is a valuable adjunct in routine gynaecological pathology. The molecular revolution has redesigned knowledge of gynaecological cancers and refined histological classification. The direct consequence has been the progressive introduction of new immunostainings for diagnostic and classification purposes. Hence, we review the routine diagnostic use of immunohistochemistry in the field of gynaecological neoplasia. We reviewed the immunomarkers useful in gynaecological pathology according to literature revision, our personal experience and research findings. We discuss the application of immunohistochemistry to reach the most accurate diagnosis in morphologically equivocal cases of gynaecological pathology and present the appropriate panel of immunomarkers in the most common scenarios of gynaecological pathology. This short review provides an updated overview of the essential immunohistochemical markers currently used in the diagnostics of gynaecological malignancies along with their molecular rationale.

Myxoid Mesenchymal Tumors of the Uterus: An Update on Classification, Definitions, and Differential Diagnosis

Tumors with a predominant myxoid stroma are rare in the uterus. When encountered, however, they pose a diagnostic challenge. Traditionally myxoid leiomyosarcoma has been the most important consideration in this category, given its adverse prognosis and deceptively bland morphology. Conventional features of malignancy are variably present; in contrast, an infiltrative tumor border is a consistent pathologic characteristic. More recently, previously under-recognized lesions have been identified, in part due to our growing knowledge of their underlying molecular alterations: uterine inflammatory myofibroblastic tumor frequently harbors ALK rearrangements and a novel ZC3H7B-BCOR gene fusion has been described in a subset of myxoid high-grade endometrial stromal sarcomas. These tumors need to be distinguished from myxoid leiomyosarcoma, as by comparison have a less aggressive course and are amenable to targeted treatments. In addition, uterine mesenchymal tumors with malignant potential need to be distinguished from benign tumors and epithelial and mixed malignancies. This review aims to discuss our current understanding of the most common uterine myxoid neoplasms: their clinical features, their distinguishing histopathologic, immunohistochemical, and molecular features and the clues and pitfalls in their diagnosis.

[New features in the 2014 WHO classification of uterine neoplasms]

The 2014 World Health Organization (WHO) classification of uterine tumors revealed simplification of the classification by fusion of several entities and the introduction of novel entities. Among the multitude of alterations, the following are named: a simplified classification for precursor lesions of endometrial carcinoma now distinguishes between hyperplasia without atypia and atypical hyperplasia, the latter also known as endometrioid intraepithelial neoplasia (EIN). For endometrial carcinoma a differentiation is made between type 1 (endometrioid carcinoma with variants and mucinous carcinoma) and type 2 (serous and clear cell carcinoma). Besides a papillary architecture serous carcinomas may show solid and glandular features and TP53 immunohistochemistry with an "all or null pattern" assists in the diagnosis of serous carcinoma with ambiguous features. Neuroendocrine neoplasms are categorized in a similar way to the gastrointestinal tract into well differentiated neuroendocrine tumors and poorly differentiated neuroendocrine carcinomas (small cell and large cell types). Leiomyosarcomas of the uterus are typically high grade and characterized by marked nuclear atypia and lively mitotic activity. Low grade stromal neoplasms frequently show gene fusions, such as JAZF1/SUZ12. High grade endometrial stromal sarcoma is newly defined by cyclin D1 overexpression and the presence of the fusion gene YWHAE/FAM22 and must be distinguished from undifferentiated uterine sarcoma. Carcinosarcomas (malignant mixed Mullerian tumors MMMT) show biological and molecular similarities to high-grade carcinomas.

The mitosis-specific marker phosphohistone-H3 (PHH3) is an independent prognosticator in uterine smooth muscle tumours: an outcome-based study

AIMS

Accurate mitosis counting, which is important in the diagnosis of uterine smooth muscle tumours (USMTs), is often difficult and subjective. The mitosis-specific immunohistochemical marker phosphohistone-H3 (PHH3) has been shown to be diagnostically useful, but its expression, in relation to outcome, has not been thoroughly investigated. The aim of this study is to evaluate PHH3 as a diagnostic and prognostic marker in USMTs.

METHODS AND RESULTS

PHH3 expression was evaluated in 55 leiomyosarcomas (LMSs), 26 smooth muscle tumours of uncertain malignant potential (STUMPs), 18 leiomyomas with bizarre nuclei (LBN), and 12 leiomyomas (LMs). Scores were expressed as counts per 10 high-power fields (HPFs). Median follow-up durations of patients with LMS, STUMP, LBN and LM were, respectively, 39, 78, 65.5 and 49.5 months. Twenty-eight patients with LMSs (50.9%) died, and two (7.7%) patients with STUMPs experienced recurrence. The median PHH3 scores for LMSs were significantly higher than those for other categories of tumour. A score of ≥29/10 HPFs was also independently associated with a poor outcome. To test whether the PHH3 score could distinguish between benign USMTs with atypical histology and those that were clinically malignant, two biological groups were further delineated. Patients in group 1 (18 LBNs and 24 STUMPs) all had an uneventful outcome, whereas patients in group 2 (two recurrent STUMPs and 32 LMSs) all had a recurrence or tumour-related death. Median PHH3 scores for the two groups were, respectively, 2/10 HPFs and 27/10 HPFs. A PHH3 score of ≥7/10 HPFs was highly associated with malignancy.

CONCLUSION

PHH3 is useful in evaluation of the biological behaviour of USMTs, and may serve as a prognostic indicator for LMSs.

Risk of Occult Uterine Sarcoma in Presumed Uterine Fibroids

Symptomatic fibroids are a common indication for hysterectomy or myomectomy. Although rare, unexpected gynecologic malignancies in presumed fibroids have been documented. In cases where tissue retrieval is performed through morcellation, there is increasing concern that intra-abdominal dispersion of occult uterine malignancies may lead to peritoneal dissemination and worse outcomes. We examined the available literature to determine the prevalence of all uterine cancers in women undergoing hysterectomy or myomectomy for benign uterine disease, with attention to the risk of morcellating occult uterine sarcomas. We also reviewed the available tools for preoperative discrimination between benign and malignant uterine disease.

Immunohistochemical profile of uterine leiomyomas; a comparison between different subtypes

BACKGROUND

Of all Smooth muscle tumours originating from uterus are leiomyomas are the most common ones. Benign nature and smooth muscle origination of leiomyomas can be easily documented via histological examination. In present study it was tried to examine immunohistochemical profile of leiomyomas with different subtypes.

MATERIAL AND METHODS

In this cross-sectional study 64 cases of smooth muscle tumors originating from uterus were included in study. As a control group 12 cases of conventional leiomyomas were selected. Then estrogen receptor, progesterone receptor, p53 and ki-67 were assessed. Statistical analysis was conducted using SPSS 16.0.

RESULTS

P 53 and ki-67 antibody status was diffusely positive in 12 out of 24 cases (50%) of leiomyosarcomas. Leiomyomas with bizzare nuclei were stained with Ki67 proliferative marker less than those in obviously malignant cases (P < 0.001). Estrogen and progesterone receptors had a reverse correlation with tumours malignancy potential.

CONCLUSION

Since p53 is known as an important inhibitory trigger for proliferative cycle of cells, in current study it was concluded that p53 inhibitory role decreases as malignancy potential increases, also tumors dependence on steroids via steroid receptors decreases as malignancy potential increases.

Prognostic value of Ki67 in localized prostate carcinoma: a multi-institutional study of >1000 prostatectomies

BACKGROUND

Expanding interest in and use of active surveillance for early state prostate cancer (PC) has increased need for prognostic biomarkers. Using a multi-institutional tissue microarray resource including over 1000 radical prostatectomy samples, we sought to correlate Ki67 expression captured by an automated image analysis system with clinicopathological features and validate its utility as a clinical grade test in predicting cancer-specific outcomes.

METHODS

After immunostaining, the Ki67 proliferation index (PI) of tumor areas of each core (three cancer cores/case) was analyzed using a nuclear quantification algorithm (Aperio). We assessed whether Ki67 PI was associated with clinicopathological factors and recurrence-free survival (RFS) including biochemical recurrence, metastasis or PC death (7-year median follow-up).

RESULTS

In 1004 PCs (∼4000 tissue cores) Ki67 PI showed significantly higher inter-tumor (0.68) than intra-tumor variation (0.39). Ki67 PI was associated with stage (P<0.0001), seminal vesicle invasion (SVI, P=0.02), extracapsular extension (ECE, P<0.0001) and Gleason score (GS, P<0.0001). Ki67 PI as a continuous variable significantly correlated with recurrence-free, overall and disease-specific survival by multivariable Cox proportional hazard model (hazards ratio (HR)=1.04-1.1, P=0.02-0.0008). High Ki67 score (defined as ⩾5%) was significantly associated with worse RFS (HR=1.47, P=0.0007) and worse overall survival (HR=2.03, P=0.03).

CONCLUSIONS

In localized PC treated by radical prostatectomy, higher Ki67 PI assessed using a clinical grade automated algorithm is strongly associated with a higher GS, stage, SVI and ECE and greater probability of recurrence.

TOP2A copy number and TOP2A expression in uterine benign smooth muscle tumours and leiomyosarcoma

AIMS

To examine TOP2A copy number, TOP2A expression, and its prognostic value in uterine leiomyosarcoma (LMS) and other benign smooth muscle tumours.

METHODS

We analysed 37 patients treated for uterine LMS with immunohistochemistry for protein expression and fluorescence in situ hybridisation (FISH) for copy number. Twelve cases of leiomyoma variants (LMVs), 4 smooth muscle tumours of uncertain malignant potential (STUMP) and 23 leiomyomas (LMs) were also included.

RESULTS

Eighteen patients with LMS (48.6%) were International Federation of Gynecology and Obstetrics (FIGO) stage I, six (16.2%) were stage II, four (10.8%) were stage III, and nine (24.3%) were stage IV. Twenty-one (56.8%) patients with LMS showed high expression of TOP2A. Greater TOP2A levels were found in patients with stage ≥II disease compared with stage I and also in high mitotic index tumours (>20/10 HPF (high power field)). Eleven (36.7%) cases had abnormal TOP2A copy numbers. There was no link between TOP2A copy number and TOP2A expression. All patients with benign smooth muscle tumours had low TOP2A immunohistochemical expression and one (7.7%) patient had TOP2A amplification. TOP2A expression and TOP2A copy number had no impact on disease outcomes. Only the presence of disease outside of the uterus negatively impacted survival compared with early disease (53.4 vs 15.8 months; p<0.001).

CONCLUSIONS

TOP2A is highly expressed in advanced LMS but not in non-malignant diseases. TOP2A expression does not correlate with FISH results and does not predict outcome. TOP2A levels are higher in high-mitotic index tumours and in more advanced stages of disease.

Practical issues in uterine pathology from banal to bewildering: the remarkable spectrum of smooth muscle neoplasia

Among mesenchymal tumors of the uterus, smooth muscle neoplasms are most common. The wide morphologic spectrum, especially within the category of leiomyomas, is responsible for diagnostic problems more frequently with leiomyosarcoma (including mitotically active, apoplectic, and leiomyoma with bizarre nuclei) but also with endometrial stromal tumors. In the former scenario, clinical information, gross appearance as well as strict utilization of morphologic criteria including cytologic atypia, mitotic activity, and tumor cell necrosis are clues in establishing the correct diagnosis. It is important to keep in mind that mitotic rate thresholds vary for the different subtypes of leiomyosarcoma. Of note, p16 should be used with caution in supporting a diagnosis of leiomyosarcoma as it is often positive in leiomyomas with bizarre nuclei and leiomyomas with apoplectic change (in the latter most frequently and more intense near areas of necrosis). MED12 mutations have also a very limited role in this differential diagnosis. Endometrial stromal tumors are by far, less common than smooth muscle tumors, but can be confused with leiomyosarcomas if they are associated with an undifferentiated uterine sarcoma and the low-grade component is overlooked or they have a myxoid/fibroblastic morphology. The differential diagnosis may be confounded if the latter is associated with a high-grade endometrial stromal sarcoma. It is important to highlight that CD10 is not a reliable marker in these differentials and should be used as a part of a panel of antibodies that also includes desmin and h-caldesmon. Two other recently categorized tumors in the uterus that merit special mention are PEComa and inflammatory myofibroblastic tumor as they enter in the differential diagnosis of smooth muscle tumors. PEComa may be part of the tuberous sclerosis syndrome and may show either a predominantly epithelioid or spindle morphology or combination thereof. Rarely, it may contain melanin pigment. There is variable positivity for HMB-45, MelanA, MiTF, and CathepsinK, and some tumors have been shown to express TFE-3 especially when associated with "clear cell" morphology. Patients with adverse outcome have tumors with ≥2 of the following features: ≥5 cm, infiltration, high-grade cytologic features, mitotic rate ≥1/50 high-power fields, necrosis, or lymphovascular invasion. Inflammatory myofibroblastic tumor is important to recognize as it often mimics myxoid smooth muscle tumors, either benign or malignant. The presence of an associated lymphoplasmacytic infiltrate should alert to that possibility and ALK studies (immunostain or FISH) are helpful in establishing this diagnosis. These tumors can behave in a malignant manner if large, associated with abundant myxoid change, brisk mitotic rate or show tumor cell necrosis.

EMMPRIN (CD147) Expression in Smooth Muscle Tumors of the Uterus

Smooth muscle tumors of the uterus are the most common mesenchymal tumors of the gynecologic tract. The vast majority of these are benign leiomyomas that present no diagnostic difficulty. Because some benign smooth muscle tumors may degenerate and uncommon variants exist, the diagnosis can be challenging in some cases. The goal of this research was to investigate EMMPRIN expression in leiomyomas, leiomyoma variants, and leiomyosarcomas (LMS) to determine whether it has a potential role in differential diagnosis. EMMPRIN expression was investigated with immunohistochemistry in 103 uterine smooth muscle tumors, which included 19 usual leiomyomas, 52 leiomyoma variants, and 32 LMS. They were evaluated on the basis of staining extent, intensity, and also their combined score, and the groups were compared. EMMPRIN expression was present in 3 of 19 (15.7%) usual leiomyomas, 23 of 52 (44.3%) leiomyoma variants, and 28 of 32 (87.5%) LMS. There were statistically significant differences in staining extent and intensity, and also for their combined scores, between the LMS and benign groups. Although uterine smooth muscle tumors are usually diagnosed easily with conventional diagnostic criteria, the differentiation of LMS from some variants of leiomyoma can be challenging based soley on morphology. EMMPRIN may be a valuable immunohistochemical marker for differentiating LMS from benign smooth muscle tumors in problematic cases.

The Utility of Immunohistochemistry in the Differential Diagnosis of Gynecologic Disorders

Context

Immunohistochemistry has assumed an increasing role in the identification and characterization of gynecologic disorders including lesions with deceptively bland morphology, uncommon and underdiagnosed neoplasms, and neoplasms with specific genetic alterations associated with overexpression or loss of expression of specific proteins. The diagnostic accuracy has been significantly improved owing to the discovery and increasing experience with the tumor-associated biomarkers, and the increasing demand for precise tumor classification to assess suitability for the expanding therapeutic modalities including clinical trials.

Objective

To differentiate lesions of the gynecologic tract through the use of effective immunohistochemical panels.

Data Sources

Literature review and authors' personal practice experience.

Conclusions

The application of diagnostic and prognostic immunohistochemical panels has enabled pathologists to better guide therapeutic decisions and to better predict the clinical outcome. It is now well established that the use of ancillary testing, including immunohistochemistry, has a significant power in the identification, differentiation, and classification of reactive, premalignant, and malignant gynecologic disorders. This article discusses the utilities and pitfalls of the commonly used immunohistochemical markers in the context of overlapping morphologic features encountered in the uterus, ovaries, and fallopian tubes.

Uterine leiomyomas with bizarre nuclei: a clinicopathologic study of 59 cases

Leiomyoma with bizarre nuclei (LM-BN) is an uncommon tumor with histologic features (mononucleated or multinucleated bizarre cells that may have a diffuse distribution, prominent nucleoli, and karyorrhectic nuclei that may mimic atypical mitoses) that often causes confusion with leiomyosarcoma. Fifty-nine LM-BNs were collected from our consultation files over the years 2000 to 2011. Features recorded included patient age, therapy, tumor size, border, gross appearance, density and distribution of BN, mitotic count, karyorrhectic nuclei, prominent nucleoli, cells with conspicuous dense eosinophilic cytoplasm (rhabdoid-like), vascular changes and type of vasculature, and presence of necrosis and its nature. Follow-up information was obtained for all patients. Patients ranged in age from 25 to 75 (average 45) years (11 patients between 25 and 35 y, 20 between 36 and 45 y, 22 between 46 and 55 y, and 6 between 56 and 75 y). Forty-two underwent hysterectomy and 17 myomectomy. For 51 tumors gross findings were known. Forty (78%) had a solid white and whorled cut surface and 11 (22%) a yellow appearance. Five (10%) neoplasms showed prominent cystic degeneration, and hemorrhage and/or necrosis was seen in 9 (18%). Forty-five LM-BNs had a pushing margin with the surrounding myometrium, whereas 1 showed irregular borders. Margins could not be ascertained in the slides available in 13 cases. Twenty-eight (48%), 19 (32%), and 12 (20%) LM-BN showed low, intermediate, and high BN density. Eighteen (30%) tumors showed diffuse, 26 (44%) showed multifocal, and 15 (26%) had focal BN distribution. Mitotic counts ranged from 0 to 7/10 high-power fields (HPF) (average 1 to 2/10 HPF). Thirty-seven (63%) had <2/10 HPF, 19 (32%) had 2 to 5 mitoses/10 HPF, and in 3 tumors (5%) mitotic counts were 6, 7, and 7/10 HPF (2 with focal and 1 with diffuse BN). All but 4 LM-BNs showed karyorrhectic nuclei, striking in 12 neoplasms, mimicking atypical mitoses. Nineteen (32%) LMs had prominent eosinophilic nucleoli surrounded by a clear halo. Ischemic necrosis was detected in 21 (36%) LM-BN. Rhabdoid-like cells were noted in 24 (41%) tumors. All patients had no evidence of recurrence, ranging from 1 to 13 years (overall average 6 y; in patients with myomectomy 6.3 y with a range of 2.6 to 11 y). Our results corroborate that LM-BN is associated with a favorable outcome even in those patients only treated by myomectomy and highlights that a conservative approach can be undertaken in these patients, as many of them are of reproductive age. Because of the favorable outcome, the term LM-BN is preferable to alternative terminology including "atypical leiomyoma."

Preoperative diagnosis of usual leiomyoma, atypical leiomyoma, and leiomyosarcoma

Uterine smooth muscle tumors (SMTs) are common pelvic tumors in women, and most of them are diagnosed as usual leiomyoma (UL). Exclusion of malignant disease is important in the management of SMTs. However, differentiation of SMTs remains difficult. In this study, we aimed to improve the preoperative diagnosis of SMTs. We examined 21 ULs, 7 atypical leiomyomas (ALs), and 6 leiomyosarcomas (LMSs), all of which were diagnosed by uterine tumor biopsy. Immunohistochemical findings (low-molecular-mass polypeptide 2 (LMP2) and Ki-67) and clinical features (serum lactate dehydrogenase level and menopause) were evaluated. Statistically significant differences in the expression of LMP2 and Ki-67 were observed between UL and AL and between UL and LMS. The combined LMP2 and Ki-67 score was significantly different between UL and AL, between UL and LMS, and between AL and LMS. The combined immunohistochemistry and clinical findings score (total score) was also significantly different between pathological types. The findings of this study suggest that the accuracy of the preoperative diagnosis of SMTs may be improved by using a combination of immunohistochemical and clinical findings.