Uterine smooth muscle tumors: utility of classification by proliferation, ploidy, and prognostic markers versus traditional histopathology

Could the mitotic count improve personalized prognosis in melanoma patients?

A number of studies have indicated that the mitotic rate may be a predictive factor for poor prognosis in melanoma patients. The aim of this study was to investigate whether the mitotic rate is associated with other prognostic clinical and anatomopathological characteristics. After adjusting for other anatomopathological characteristics, we then verified the prognostic value of the number of mitoses, determining in which population subgroup this variable may have greater prognostic significance on 3-year mortality. The Veneto Cancer Registry (Registro Tumori del Veneto-RTV), a high-resolution population-based dataset covering the regional population of approximately 4.9 million residents, served as the clinical data source for the analysis. Inclusion criteria included all incident cases of invasive cutaneous malignant melanoma recorded in the RTV in 2015 (1,050 cases) and 2017 (1,205 cases) for which the number of mitoses was available. Mitotic classes were represented by Kaplan-Meier curves for short-term overall survival. Cox regression calculated hazard ratios in multivariable models to evaluate the independent prognostic role of different mitotic rate cut-offs. The results indicate that the mitotic rate is associated with other survival prognostic factors: the variables comprising the TNM stage (e.g., tumor thickness, ulceration, lymph node status and presence of metastasis) and the characteristics that are not included in the TNM stage (e.g., age, site of tumor, type of morphology, growth pattern and TIL). Moreover, this study demonstrated that, even after adjusting for these prognostic factors, mitoses per mm2 are associated with higher mortality, particularly in T2 patients. In conclusion, these findings revealed the need to include the mitotic rate in the histological diagnosis because it correlates with the prognosis as an independent factor. The mitotic rate can be used to develop a personalized medicine approach in the treatment and follow-up monitoring of melanoma patients.

Epigenomic and enhancer dysregulation in uterine leiomyomas

BACKGROUND

Uterine leiomyomas, also known as uterine fibroids or myomas, are the most common benign gynecological tumors and are found in women of reproductive and postmenopausal age. There is an exceptionally high prevalence of this tumor in women by the age of 50 years. Black women are particularly affected, with an increased incidence, earlier age of onset, larger and faster growing fibroids and greater severity of symptoms as compared to White women. Although advances in identifying genetic and environmental factors to delineate these fibroids have already been made, only recently has the role of epigenomics in the pathogenesis of this disease been considered.

OBJECTIVE AND RATIONALE

Over recent years, studies have identified multiple epigenomic aberrations that may contribute to leiomyoma development and growth. This review will focus on the most recent discoveries in three categories of epigenomic changes found in uterine fibroids, namely aberrant DNA methylation, histone tail modifications and histone variant exchange, and their translation into altered target gene architecture and transcriptional outcome. The findings demonstrating how the altered 3D shape of the enhancer can regulate gene expression from millions of base pairs away will be discussed. Additionally, translational implications of these discoveries and potential roadblocks in leiomyoma treatment will be addressed.

SEARCH METHODS

A comprehensive PubMed search was performed to identify published articles containing keywords relevant to the focus of the review, such as: uterine leiomyoma, uterine fibroids, epigenetic alterations, epigenomics, stem cells, chromatin modifications, extracellular matrix [ECM] organization, DNA methylation, enhancer, histone post-translational modifications and dysregulated gene expression. Articles until September 2021 were explored and evaluated to identify relevant updates in the field. Most of the articles focused on in the discussion were published between 2015 and 2021, although some key discoveries made before 2015 were included for background information and foundational purposes. We apologize to the authors whose work was not included because of space restrictions or inadvertent omission.

OUTCOMES

Chemical alterations to the DNA structure and of nucleosomal histones, without changing the underlying DNA sequence, have now been implicated in the phenotypic manifestation of uterine leiomyomas. Genome-wide DNA methylation analysis has revealed subsets of either suppressed or overexpressed genes accompanied by aberrant promoter methylation. Furthermore, differential promoter access resulting from altered 3D chromatin structure and histone modifications plays a role in regulating transcription of key genes thought to be involved in leiomyoma etiology. The dysregulated genes function in tumor suppression, apoptosis, angiogenesis, ECM formation, a variety of cancer-related signaling pathways and stem cell differentiation. Aberrant DNA methylation or histone modification is also observed in altering enhancer architecture, which leads to changes in enhancer-promoter contact strength, producing novel explanations for the overexpression of high mobility group AT-hook 2 and gene dysregulation found in mediator complex subunit 12 mutant fibroids. While many molecular mechanisms and epigenomic features have been investigated, the basis for the racial disparity observed among those in the Black population remains unclear.

WIDER IMPLICATIONS

A comprehensive understanding of the exact pathogenesis of uterine leiomyoma is lacking and requires attention as it can provide clues for prevention and viable non-surgical treatment. These findings will widen our knowledge of the role epigenomics plays in the mechanisms related to uterine leiomyoma development and highlight novel approaches for the prevention and identification of epigenome targets for long-term non-invasive treatment options of this significantly common disease.

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.

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.

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.

Magnetic Resonance Imaging Grading System for Preoperative Diagnosis of Leiomyomas and Uterine Smooth Muscle Tumors

STUDY OBJECTIVE

To evaluate a new magnetic resonance imaging (MRI) grading system for preoperative differentiation between benign and variant-type uterine leiomyomas including smooth muscle tumors of uncertain malignant potential (STUMPs).

DESIGN

Retrospective analysis (Canadian Task Force classification III).

SETTING

Teaching hospital (Teine Keijinkai Hospital).

PATIENTS

Three-hundred thirteen patient medical records were retrospectively reviewed if treated for uterine myomas and diagnosed with variant type leiomyomas or STUMPs (n = 27) or benign, typical leiomyomas (n = 286) and treated between January 2012 and December 2014.

INTERVENTION

Uterine myoma classifications using MRI findings according to a 5-grade system (grades I-V) based on 3 elements.

MEASUREMENTS AND MAIN RESULTS

Uterine myoma MRI classifications were based on 3 elements: T2-weighted imaging (high or low), diffusion-weighted imaging (high or low), and apparent diffusion coefficient values (high or low; apparent diffusion coefficient < 1.5 × 10^-3 mm²/sec was considered low). Grades I to II were designated as typical or benign leiomyomas, grade III as degenerated leiomyomas, and grades IV to V as variant type leiomyomas or STUMPs. Accuracy levels were 98.9%, 100%, 94.3%, 58.8%, and 41.9% for grades I through V lesions, respectively. The grades were divided into 2 groups to discriminate benign leiomyomas and STUMPs (grades I-III were considered negative and grades IV-V positive). Grades IV to V scored 85.2% for sensitivity, 91.3% for specificity, 47.9% positive predictive value, 98.5% negative predictive value, a 9.745 positive likelihood ratio, and a .162 negative likelihood ratio.

CONCLUSION

This novel MRI grading system for uterine myomas may be beneficial in differentiating benign leiomyomas from STUMPs or variant type leiomyomas and could be a future effective presurgical assessment tool.

Potential Therapeutic Targets in Uterine Sarcomas

Uterine sarcomas are rare tumors accounting for 3,4% of all uterine cancers. Even after radical hysterectomy, most patients relapse or present with distant metastases. The very limited clinical benefit of adjuvant cytotoxic treatments is reflected by high mortality rates, emphasizing the need for new treatment strategies. This review summarizes rising potential targets in four distinct subtypes of uterine sarcomas: leiomyosarcoma, low-grade and high-grade endometrial stromal sarcoma, and undifferentiated uterine sarcoma. Based on clinical reports, promising approaches for uterine leiomyosarcoma patients include inhibition of VEGF and mTOR signaling, preferably in combination with other targeted or cytotoxic compounds. Currently, the only targeted therapy approved in leiomyosarcoma patients is pazopanib, a multitargeted inhibitor blocking VEGFR, PDGFR, FGFR, and c-KIT. Additionally, preclinical evidence suggests effect of the inhibition of histone deacetylases, tyrosine kinase receptors, and the mitotic checkpoint protein aurora kinase A. In low-grade endometrial stromal sarcomas, antihormonal therapies including aromatase inhibitors and progestins have proven activity. Other potential targets are PDGFR, VEGFR, and histone deacetylases. In high-grade ESS that carry the YWHAE/FAM22A/B fusion gene, the generated 14-3-3 oncoprotein is a putative target, next to c-KIT and the Wnt pathway. The observation of heterogeneity within uterine sarcoma subtypes warrants a personalized treatment approach.

An analysis of 37 patients with uterine leiomyosarcoma at a high-volume cancer center

Objective:

To evaluate the clinicopathologic characteristics, treatment methods, survival, and prognosis of uterine leiomyosarcoma (ULMS).

Materials and Methods:

All patients with ULMS who were treated between January 1998 and October 2012 were retrospectively reviewed. A total of 37 women who met the inclusion criteria were included in the present study. Univariate and multivariate analyses were used to identify the risk factors for overall survival (OS) and progression-free survival (PFS).

Results:

The majority of patients had stage 1 disease (IA, n=9 (24.3%); IB, n=23 (62.1%)). All patients underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy. Additionally, only pelvic, and pelvic plus para-aortic lymphadenectomy was performed in 5 (13.5%) and 8 (21.6%) women, respectively. Adjuvant treatment was administered to 27 (72.9%) patients. Patients who did not receive adjuvant therapy had stage 1 disease. Recurrences occurred in 5 (13.5%) patients. The median follow-up period was 71 months (range 1-158 months). The 5-year PFS and OS rates were 68% and 74%, for all patients. The 5-year OS rates for women with stage 1 and ≥ stage 2 disease were 82% and 27%, respectively. Multivariate analysis confirmed stage 1 disease as the only independent predictor of both PFS (Odds ratio (OR) 10.955, 95% confidence interval (CI) 1.686-71.181, (p=0.012)) and OS (OR 57.429, 95% CI 3.287-1003.269, (p=0.006)).

Conclusions:

Extensive surgery is not associated with prognosis and stage 1 disease is the only independent good prognostic factor for survival in patients with ULMS.

Molecular analyses of 6 different types of uterine smooth muscle tumors: Emphasis in atypical leiomyoma

BACKGROUND

Uterine smooth muscle tumors (USMTs) constitute a group of histologic, genetic, and clinical heterogeneous tumors that include at least 6 major histologically defined tumor types: leiomyoma (ULM), mitotically active leiomyoma (MALM), cellular leiomyoma (CLM), atypical leiomyoma (ALM), uncertain malignant potential (STUMP), and leiomyosarcoma (LMS). Apart from ULM and LMS, the nature of these variants is not well defined.

METHODS

A total of 167 cases of different USMT variants were collected, reviewed, and diagnostically confirmed based on the World Health Organization and Stanford schemes. These included 38 cases of LMS, 18 cases of STUMP, 42 cases of ALM, 22 cases of CLM, 7 cases of MALM, and 40 cases of ULM. Molecular analysis included selected microRNAs (miRNAs), oncogenes, and tumor suppressors that are highly relevant to USMT.

RESULTS

Overall, 49% (17/35) of LMS cases and 7% (1/14) of STUMP cases died due to their USMT, but no deaths were attributed to ALM. miRNA profiling revealed that ALM and LMS shared similar miRNA signatures. P53 mutations and PTEN deletions were significantly higher in LMS, ALM, and STUMP compared with other USMT variants (P < .01). In contrast, MED12 mutations were extremely common in ULM and MALM (> 74%) but were significantly less common (< 15%) in CLM, ALM, STUMP, and LMS (P < .01).

CONCLUSION

Six types of USMT have different gene mutation fingerprints. ALM shares many molecular alterations with LMS. Our findings suggest that ALM may be a precursor lesion of LMS or have similar genetic changes during its early stage.

Mitotic rate in melanoma: prognostic value of immunostaining and computer-assisted image analysis

The prognostic value of mitotic rate in melanoma is increasingly recognized, particularly in thin melanoma in which the presence or absence of a single mitosis/mm can change staging from T1a to T1b. Still, accurate mitotic rate calculation (mitoses/mm) on hematoxylin and eosin (H&E)-stained sections can be challenging. Antimonoclonal mitotic protein-2 (MPM-2) and antiphosphohistone-H3 (PHH3) are 2 antibodies reported to be more mitosis-specific than other markers of proliferation such as Ki-67. We used light microscopy and computer-assisted image analysis software to quantify MPM-2 and PHH3 staining in melanoma. We then compared mitotic rates by each method with conventional H&E-based mitotic rate for correlation with clinical outcomes. Our study included primary tissues from 190 nonconsecutive cutaneous melanoma patients who were prospectively enrolled at New York University Langone Medical Center with information on age, gender, and primary tumor characteristics. The mitotic rate was quantified manually by light microscopy of corresponding H&E-stained, MPM-2-stained, and PHH3-stained sections. Computer-assisted image analysis was then used to quantify immunolabeled mitoses on the previously examined PHH3 and MPM-2 slides. We then analyzed the association between mitotic rate and both progression-free and melanoma-specific survival. Univariate analysis of PHH3 found significant correlation between increased PHH3 mitotic rate and decreased progression-free survival (P=0.04). Computer-assisted image analysis enhanced the correlation of PHH3 mitotic rate with progression-free survival (P=0.02). Regardless of the detection method, neither MPM-2 nor PHH3 offered significant advantage over conventional H&E determination of mitotic rate.

Immunolocalization of VEGF, VEGF receptors, EGF-R and Ki-67 in leiomyoma, cellular leiomyoma and leiomyosarcoma

Angiogenic factors, such as vascular endothelial growth factor (VEGF), its receptors and epidermal growth factor receptor (EGF-R), are involved in increased progression in many carcinomas. The aim of this study was to investigate the role of angiogenesis and immunolocalization of VEGF, its receptors, EGF-R and Ki 67 in leiomyomas and leiomyosarcomas using an indirect immunohistochemical method. Samples from patients with leiomyoma, cellular leiomyoma and cellular leiomyosarcoma (n=20 per group) were fixed in 10% formalin and processed using routine paraffin protocols. Following initial histological analysis, samples were immunostained with primary antibodies for VEGF, VEGFR-1, VEGFR-2, EGF-R and Ki-67 using an indirect avidin-biotin peroxidase method. Immunostaining intensities were evaluated as mild, moderate or strong and a semi-quantitative method (H-Score) was used to compare the samples. While mild/moderate EGF-R immunostaining and moderate immunostaining for VEGF and its receptors were observed in samples of leiomyomas, much less immunoreactivity was observed in cellular leiomyomas. All immunoreactivities and immune-stained cells increased in leiomyosarcomas. When scores of intensity and percentage of positive staining cells were compared, all immunoreactivities were shown to be significantly increased in leiomyosarcomas compared to leiomyomas. These results suggest that in leiomyosarcoma, angiogenic factors, such as VEGF, its receptors and EGF-R, may be involved in tumor angiogenesis. Active tumor cells can trigger angiogenesis, interaction with surrounding tissue and in the tissue itself initiating angiogenic activity. Angiogenic growth factors play an important role and induce malignant transformation through both autocrine and paracrine mechanisms. Anti-angiogenic agents may provide a novel therapeutic approach for the treatment of leiomyosarcoma.

Uterine leiomyosarcoma arising in leiomyoma: clinicopathological study of four cases and literature review

In this study we examined four cases of leiomyosarcoma (LMS) arising in leiomyoma (LM). The patients ranged from 40 to 64 years old. Symptoms were unspecific and preoperative diagnosis of LMS had not been made. Size of the tumors ranged from 4 cm to 20.5 cm. All patients were in stage I and no patients developed recurrent disease. Histologically, the LMS component showed moderate to severe cytological atypia and an increased mitotic count in all cases. Tumor cell necrosis in the LMS was seen in three cases. Associated LM component was cellular in one case. The LMS component showed p53 expression in three of four cases and p16 expression was seen in two cases. The LM component lacked p53 expression in all cases and demonstrated p16 expression in two cases, including one case of cellular LM. In all cases, Ki-67-positive cells were less than 5% in the LM component and more than 25-30% in the LMS component. This study reveals that: (i) malignant transformation can occur even in relatively small LM; (ii) patients with LMS with an LM component have a favorable prognosis; and (iii) immunohistochemical examination of p53, p16 and Ki-67 is useful for identification of malignant focus.

Immunoglobulin G is present in a wide variety of soft tissue tumors and correlates well with proliferation markers and tumor grades

BACKGROUND

The traditional view that immunoglobulin (Ig) is produced only by B lymphocytes has been challenged, because it has been demonstrated that Ig genes and proteins are expressed in epithelial cancer cells. However, whether Ig expression in nonlymphoid cells is limited to epithelial cells is unclear. Because sarcomas differ distinctly from carcinomas in their biologic and clinical features, the authors investigated the question of nonlymphoid IgG expression in soft tissue lesions.

METHODS

Immunohistochemistry, in situ hybridization, and polymerase chain reaction (PCR) were used to demonstrate IgG expression in 80 soft tissue lesions. The correlation between Ig expression and proliferation markers (proliferating cell nuclear antigen [PCNA], Ki-67, and cyclin D1) in sarcomas was investigated by immunohistochemical and statistical analyses.

RESULTS

Igkappa was identified in 97.4% of sarcomas and in 31.7% of benign lesions by immunohistochemistry. The difference was statistically significant (P < .01). Messenger RNA from the IgG1 heavy-chain constant region was also detected by in situ hybridization. Variable-diversity-joining recombination sequences of both heavy and light chains were obtained by PCR and sequencing. Moreover, the labeling index of PCNA, Ki-67, and cyclin D1 was much higher in sarcomas with high Igkappa expression than in sarcomas with low Igkappa expression (P < .01 for PCNA and cyclin D1; P < .001 for Ki-67). There were more grade 3 sarcomas with high Igkappa expression compared with grade 1 and 2 sarcomas (P < .05).

CONCLUSIONS

IgG was identified in a wide variety of soft tissue tumors and correlated well with proliferation markers and tumor grades. IgG may be a useful marker for cell proliferation in sarcomas.

Uterine smooth muscle tumors of uncertain malignant potential (STUMP): a clinicopathologic analysis of 16 cases

BACKGROUND

The current World Health Organization classification indicates that a uterine smooth muscle tumor that cannot be histologically diagnosed as unequivocally benign or malignant should be termed "smooth muscle tumor of uncertain malignant potential" (STUMP). STUMPs represent a heterogeneous group of rare tumors that have been the subject of only a few published studies, some of which lack detailed clinicopathologic details and/or follow-up data. More recently, it has been suggested that immunohistochemical staining may be helpful in the diagnosis of STUMPs.

DESIGN

The clinicopathologic features of 16 cases of STUMP that exhibited usual smooth muscle differentiation, diagnosed between 1992 and 2006 from 11 hospitals, were studied and classified into 4 subgroups using terminology and criteria described by Stanford investigators. Immunohistochemical stains for p16, p53, MIB1 (ki-67), and estrogen and progesterone receptors were performed. The results were compared with those in the literature.

RESULTS

The tumors were classified as follows: 6 as "atypical leiomyoma with limited experience", 7 as "smooth muscle tumor of low malignant potential", 2 as "atypical leiomyoma, low risk of recurrence," and 1 as "mitotically active leiomyoma, limited experience." Follow-up was 21 to 192 months (mean, 80.8 and median, 51.5). Only 2 tumors recurred, at 15 and 51 months, respectively; both were atypical leiomyoma with limited experience (multifocal moderate-to-severe atypia, no tumor cell necrosis, and mitotic counts of 4 and 5 mitotic figures /10 high-power fields, respectively). Both tumors had areas that were indistinguishable from benign leiomyoma and both had diffuse immunoreactivity for p16 and p53. Six other tumors that had focal staining for these markers all had a benign outcome. Both patients with recurrence were alive at last follow-up (at 40 and 74 mo). All the other patients were alive and disease-free.

CONCLUSIONS

This and other studies suggest that uterine tumors classified as STUMPs using criteria proposed by Stanford investigators are usually clinically benign but should be considered tumors of low malignant potential because they can occasionally recur, in some cases, years after hysterectomy. After a mean follow-up of 80.8 months, only 2 of 16 tumors in this study recurred. Both of the latter tumors fulfilled the criteria for atypical leiomyoma with limited experience. Notably, the 2 recurrent tumors were the only ones that were strongly immunoreactive for p16 and p53, supporting earlier observations that these markers may be helpful in the prediction of the behavior of STUMPs. Patients diagnosed with STUMPs should receive long-term surveillance.

A panel of antibodies to determine site of origin and malignancy in smooth muscle tumors

Leiomyosarcomas are malignant smooth muscle tumors that occur most commonly in the gynecologic tract and soft tissue. There are different diagnostic criteria of malignancy for smooth muscle tumors arising at gynecologic and soft tissue sites and they may be managed differently but determining the primary site of a smooth muscle tumor can be difficult in some cases. In addition, the distinction between malignant and benign gynecologic tract smooth muscle tumors on morphologic grounds can be challenging. Using a series of tissue microarrays that contain 245 cases of leiomyosarcomas (102 gynecologic) with survival data, and 49 cases of uterine leiomyoma, we examined the ability of selected immune-markers (estrogen receptor (ER) and WT1) to distinguish between leiomyosarcomas of gynecologic and nongynecologic origin. In addition, we examined whether immunostains for p16, p53 and Ki-67 could distinguish between malignant and benign gynecologic smooth muscle tumors. ER nuclear positivity was observed in 3 and 50% of the nongynecologic and gynecologic leiomyosarcomas, respectively (P<0.001). Nuclear WT1 positivity was seen in 0 and 8% of the nongynecologic and gynecologic leiomyosarcomas, respectively (P<0.001). 87% of primary gynecologic leiomyosarcomas and 2% of uterine leiomyomas showed diffuse (>or=50% of cells) p16 staining (P<0.001). 23% of gynecologic leiomyosarcomas showed p53 immunopositivity (>or=50% of cells) whereas none of the leiomyomas were positive for p53 (P<0.001). 65% of the gynecologic leiomyosarcomas and 0% of the leiomyomas exhibited >10% Ki-67 proliferation index (P<0.001). Diffuse p16 and p53 immunopositivity and high Ki-67 proliferation index, singly or in combination, yielded an overall sensitivity of 92% and specificity of 98% for distinguishing between gynecologic leiomyosarcomas and leiomyomas and can be used as indicators of malignancy for gynecologic smooth muscle tumors. Although ER positivity can be used to support the gynecologic origin of a leiomyosarcomas, nuclear WT1 immunostaining is of little use.

Molecular Genetics of Mesenchymal Tumors of the Female Genital Tract

Mesenchymal tumors of the female genital tract are a heterogeneous group of neoplasms that can be classified based on cellular differentiation into 3 main groups: smooth muscle tumors, endometrial stromal tumors, and other differentiated and undifferentiated tumors. Genomic analysis techniques have revealed important genetic aberrations such as the t(7;17) translocation, resulting in JAZF1-JJAZ1 gene fusion, characteristic of endometrial stromal tumors. These analyses have demonstrated genetic complexity and heterogeneity in many mesenchymal tumor types. This article focuses on current understanding of the molecular genetics of mesenchymal tumors of the female genital tract, with emphasis on diagnostic and prognostic molecular features.

Smooth muscle tumors of the uterus: a practical approach

Smooth muscle tumors (SMTs) are the most frequent mesenchymal tumors of the uterus. The majority of the uterine SMTs are readily classificable as benign or malignant based on their gross and microscopic appearances. However, when unusual features are seen in some leiomyoma variants, the differential diagnosis with a leiomyosarcoma may become challenging. Moreover, diagnostic criteria for the different subtypes of leiomyosarcoma are not uniform. Finally, non-smooth muscle tumors that originate in the uterus may show overlapping histologic and even immunohistochemical features with uterine SMTs, more commonly with the spindle and epithelioid variants, complicating their correct classification. The diagnosis of malignant uterine SMTs has important prognostic and therapeutic implications. This review provides a practical approach to the diagnosis of uterine leiomyosarcoma based on a systematic assessment of histologic parameters as well as a systematic approach to its differential diagnosis based on histologic and immunohistochemical features.

Uterine leiomyosarcomas are characterized by high p16, p53 and MIB1 expression in comparison with usual leiomyomas, leiomyoma variants and smooth muscle tumours of uncertain malignant potential

AIMS

It has been suggested that p16 is overexpressed in uterine leiomyosarcomas in comparison with leiomyomas. In this study, p16 immunohistochemical expression was assessed in a variety of uterine smooth muscle tumours, including usual leiomyomas, leiomyoma variants, smooth muscle tumours of uncertain malignant potential (STUMPs) and leiomyosarcomas. The aim was to ascertain whether there are differences in p16 expression between these groups and whether p16 is of potential value in the assessment of problematic uterine smooth muscle neoplasms. p16 expression was also compared with that of p53 and MIB1.

METHODS AND RESULTS

Cases of usual leiomyoma (n = 10), leiomyoma variants (n = 27), STUMP (n = 4) and leiomyosarcoma (n = 22) were subject to p16, p53 and MIB1 immunohistochemistry. For p16, cases were evaluated with respect to both staining distribution and intensity. There was a statistically significant difference in p16 distribution (P < 0.001) and intensity (P = 0.001) between leiomyosarcomas and the other groups. There was no difference in p16 expression between usual leiomyomas, leiomyoma variants and STUMPs. There were also statistically significant differences in p53 (P = 0.014) and MIB1 (P < 0.001) immunoreactivity between leiomyosarcomas and the other groups.

CONCLUSIONS

p16 is overexpressed in uterine leiomyosarcomas compared with leiomyomas, benign leiomyoma variants and STUMPs, suggesting that p16 may be implicated in the pathogenesis of malignant uterine smooth muscle neoplasms. p16, in combination with p53 and MIB1, may be of value as an adjunct to morphological examination in the assessment of problematic uterine smooth muscle tumours, although further large-scale studies with follow-up are necessary to confirm this.

Uterine sarcomas

A wide variety of sarcomas occur in the uterus but two subtypes - leiomyosarcoma and endometrial stromal sarcoma - account for a majority of those more routinely encountered. Using the 2003 World Health Organization classification, this review focuses on six uterine sarcomas: endometrial stromal sarcoma, undifferentiated endometrial sarcoma, leiomyosarcoma, rhabomyosarcoma, angiosarcoma and liposarcoma. The epidemiological, clinical, pathological and molecular features are presented along with therapeutic approaches. Familiarity with molecular aspects of these tumors and application of novel technologies in their assessment should be encouraged as they may provide alternate therapies resulting in improved survival for the patient. Clinical information necessary for accurate diagnosis of these lesions is emphasised. A multidisciplinary approach to management of patients with uterine sarcomas is essential for optimal management.

A new scoring system using multiple immunohistochemical markers for diagnosis of uterine smooth muscle tumors

The diagnosis of uterine smooth muscle neoplasms by light microscopy is difficult. Multiple classification schemes have been proposed based on mitotic rate, nuclear atypia, and the presence or absence of necrosis. None of these classification systems has been entirely successful. This study was undertaken to evaluate the use of selected immunohistochemical and histochemical markers in differentiating these tumors, in addition to accepted morphologic criteria. Ten cases of each of the following: leiomyosarcomas (LMS), atypical leiomyomas (AL), cellular leiomyomas (CL) and usual leiomyomas (UL), were classically evaluated for histological diagnosis and were stained for Ki-67 (MIB-1), bcl-2 and p53 using monoclonal antibodies and the avidin-biotin peroxidase method, and argyrophilic nucleolar organizer region (AgNORs). The number of stained cells was counted in the most positively stained region in a 4 mm² square cover glass mounted on each slide. The mean value was calculated for each group of tumors. The data for Ki-67 (MIB-1), bcl-2, p53 and AgNOR staining respectively, were significantly higher in LMS by comparison to UL, CL or AL. Because many singular cases had superimposed data being difficult to diagnose, a new scoring system for pathological evaluation was created. The results obtained by this scoring system suggest that immunohistochemical markers Ki-67 (MIB-1), bcl-2, p53 together with the AgNOR staining could be useful, by the scoring system, as an adjunct to the current accepted morphologic criteria in differentiating smooth muscle tumors of the uterus.

Phenotypic characterization of endometrial stromal sarcoma of the uterus

Endometrial stromal sarcoma (ESS) of the uterus is a rare uterine malignancy that has not been characterized in detail. To characterize the phenotype of ESS of the uterus, we extracted RNA from ESS and the stroma of normal endometrium using a tissue microdissection system and compared the expression profiles in the two tissues. After suppression subtractive hybridization and differential screening, we detected the metastasis-associated lung adenocarcinoma transcript 1 (MALAT-1) gene as one of the major genes upregulated in ESS, and a full-length placental cDNA clone (CS0DI066YJ10) as one of the major genes downregulated. The results were confirmed by in situ hybridization in four resected specimens of ESS and 36 biopsy specimens of normal endometrial tissue. All ESS (4/4) and all cases of endometrial stromal cells in the proliferative phase (13/13) were positive for MALAT-1, but samples of normal stroma in the secretory phase and menopausal state included some that were negative or weakly positive for MALAT-1 (5/13 and 3/10, respectively). In contrast, all ESS and 12 of 13 cases of stromal cells in the proliferative phase were negative for the full-length placental cDNA clone but 10 of 13 cases of endometrial stromal cells in the secretory phase were positive for transcripts of the gene (P < 0.05). These results indicated that endometrial stromal cells have different phenotypic characteristics between proliferative and secretory phases and the tumor cells of ESS have the phenotypic character of endometrial stromal cells in the proliferative phase.

Borderline Smooth Muscle Tumors of the Uterus

At present, decision regarding where to place a uterine smooth muscle tumor that deviates from the most obvious leiomyoma and leiomyosarcoma groups still depends on time-honored conventional criteria. The focus of categorization should be the clinical outcome and not nosology. To improve accuracy in predicting clinical behavior, a multivariate approach is needed. This involves combining background clinical information, intraoperative and gross findings,multiple relevant morphologic criteria, and immunohistochemical studies. The authors believe that in future, as the number of cases with intermediate clinical outcome and morphologic features increases, and as molecular markers of prognosis are studied, managing these tumors will become more objective.

Evaluation of nucleolar organizer region (NOR) parameters in the uterine leiomyoma

Nucleolar organizer regions (NORs) were assessed in 27 women affected by uterine leiomyoma. Tissue samples obtained during surgery were silver-stained according to the method of Ploton et al. The assessed parameters were as follows: the number of argyrophylic nucleolar organizer regions (AgNORs) per nucleus, single AgNOR area, AgNOR intranuclear distribution, and AgNOR coefficient. The parameters were assessed quantitatively. It was found that the AgNOR coefficient was higher in uterine leiomyoma compared to the normal smooth muscle cells. The development of leiomyoma is associated with a marked decrease in myocyte nucleolar area, which accounts for 30% of the nucleus in the normal myometrium. With the comparable AgNOR number in the single nucleus, there were no differences in the single AgNOR granule area (1.21 microm2 +/- 0.047 and 1.11 microm2 +/- 0.025 in normal myometrium and in leiomyoma, respectively). In the normal myometrium, there was a positive correlation between nuclear area and the single AgNOR granule area, as well as between the AgNOR coefficient and the single AgNOR granule area. There was also a negative correlation between the number of granules per nucleus and their central and peripheral intranuclear distribution. The development of leiomyoma was associated with loss of all correlations observed in the control group.

The expression of Ki-67, p53, estrogen and progesterone receptors affecting survival in uterine leiomyosarcomas. A clinicopathologic study

OBJECTIVES

To evaluate the level of expression of estrogen receptor (ER), progesterone receptor (PR), p53 and Ki-67 in patients with leiomyosarcoma and to investigate the effect of these and to identify the clinical parameters on prognosis.

MATERIALS AND METHODS

Twenty-four patients operated for LMS of uterine origin between 1994 and 2003 at Istanbul Medical School, Department of Obstetrics and Gynecology and Division of Gynecologic Oncology constituted our study group. The data of all patients were updated via mail or phone. The effects of stage, grade, chemotherapy, radiotherapy, number of mitoses, presence of necrosis, Ki-67 and p53 expression, presence of estrogen and progesterone receptors on survival were evaluated.

RESULTS

The mean follow-up period of patients is 30.42 +/- 25.15 months. The mean overall survival for all LMS patients was estimated to be 48.4 +/- 10.38 months. The cumulative survival ratio in the 33rd month was 33.08. Age, menopausal status, history of prior radiotherapy, number of mitoses had no statistically significant effect on overall survival in our study although stage had a significant effect. Finding of greater than 10% steroid receptor expression has a positive effect on survival ([ER P = 0.019; log rank = 5.49] and [PR P = 0.023; log rank = 5.14]). The median value of Ki-67 was calculated to be 30. There was a survival advantage in patients with Ki-67 expression (P = 0.034; log rank = 4.49) below the median value. p53 levels had no significant effect on survival (P = 0.336; log rank = 0.92).

CONCLUSION

Surgical staging is an important prognostic factor in LMS patients, while number of mitoses and grade of the tumor also seem to affect prognosis. Contrary to the current literature, our findings suggest that estrogen and progesterone receptor positivity greater than 10% may be associated with a better prognosis.

ERBB-2 gene overexpression and amplification in uterine sarcomas

BACKGROUND

The aim of this study was to determine ERBB-2 (HER-2/neu) gene alterations in different subtypes of uterine sarcomas.

METHODS

After central review, representative biopsies were immunohistochemically stained and semiquantitatively scored as negative, weakly (1+), moderately (2+), or strongly (3+) positive. Subsequently, fluorescence in situ hybridization (FISH) was performed on cases with 2+ and 3+ expression.

RESULTS

Seventy tumors (52 primaries and 18 recurrent) were evaluated. All 10 adenosarcomas, 21 endometrial stromal sarcomas, and 10 leiomyosarcomas were negative both in the primary and recurrent setting. Twenty-two primary carcinosarcomas were scored. The epithelial component was negative/1+ in 16 (73%), 2+/3+ in five (22.5%) tumors, and could not be evaluated in one case (4.5%), whereas the sarcoma component stained negative/1+ in 21 cases (95.5%) and 3+ (4.5%) in one case. In two recurrent carcinosarcomas, the epithelial component stained 3+ in both cases, whereas the sarcoma component scored negative and 1+. Amplification of the ERBB-2 gene as determined by FISH was observed in 3/7 (43%) carcinosarcomas with 2+ or 3+ overexpression, resulting in an overall 3/22 (14%) amplification rate. One out of four undifferentiated uterine sarcomas stained 2+. ERBB-2 immunopositivity (3+) and ERBB-2 amplification by FISH were confirmed in the recurrent tumor, resulting in a gene amplification rate of 1/4 in undifferentiated uterine sarcomas.

CONCLUSION

The current results suggest absence of ERBB-2 overexpression in uterine leiomyosarcoma, uterine adenosarcoma, and endometrial stromal sarcoma, whereas the ERBB-2 gene might have a biologic role in uterine carcinosarcoma and undifferentiated uterine sarcomas.

Ki-67 expression in patients with uterine leiomyomas, uterine smooth muscle tumors of uncertain malignant potential (STUMP) and uterine leiomyosarcomas (LMS)

BACKGROUND

The aim of the current study was to evaluate the expression of Ki-67 in uterine smooth muscle tumors, comparing leiomyomas, uterine smooth muscle tumors of uncertain malignant potential (STUMP) and uterine leiomyosarcomas (LMS) and to prove the accuracy of a Ki-67 expression as a useful parameter in the diagnosis of LMS.

METHODS

Ki-67 was assessed using immunohistochemistry from paraffin-embedded tissue in 20 patients with uterine LMS, 22 cases of STUMP and 25 cases of leiomyomas.

RESULTS

Ki-67 was present in 10/20 (50%) LMS, in 0/22 (0%) STUMP and in 2/25 (8%) leiomyomas. Significant differences regarding the frequency of Ki-67 expression were observed between LMS and STUMP (p = 0.0001) as well as between LMS and leiomyomas (p = 0.002), but not between STUMP and leiomyomas (p = 0.491). Likewise, the staining intensity differed significantly between LMS and leiomyomas (p = 0.018) as well as between LMS and STUMP (p = 0.002), but not between STUMP and leiomyomas (p = 0.368).

CONCLUSIONS

Our results demonstrate that the significantly elevated Ki-67 antigen expression in LMS, which correlates well with the rapid growth of these malignant tumors, may be a useful immunohistochemical parameter to distinguish between cases of malignant smooth muscle tumors and those of uncertain or borderline histology.

Leiomyosarcoma of somatic soft tissues

Leiomyosarcoma is a rare, aggressively malignant connective tissue tumor of mature adults, which arises from smooth muscle. It occurs most frequently in the uterus, bowel, vascular tissues, and less commonly in somatic soft tissue or bone. The tumor when it arises in soft tissue has distinctive histologic features which somewhat resemble malignant fibrous histiocytoma (otherwise known as myxofibrosarcoma). The Orthopaedic Oncology Service at our institution has treated 66 patients with these lesions and thus far, 1/2 of the patients have died of disease at a mean of 3 years after discovery. Factors that increase the death rate include size of the tumor, Musculoskeletal Tumor Society Stage of disease, and to a lesser extent particularly in the lower extremities, anatomic site. Radiation and chemotherapy had little direct effect on the outcome but patients treated with surgery and adjunctive agents seemed to live longer than their cohorts treated with surgery alone. The purpose of this study is a general review of the clinical and prognostic features of this cancer.

Oral leiomyosarcoma: review of the literature and report of two cases with assessment of the prognostic and diagnostic significance of immunohistochemical and molecular markers

Leiomyosarcoma of the oral cavity is a very rare tumor that is associated with aggressive clinical behavior and low survival. In this paper, we report two new cases of leiomyosarcoma affecting the mandibular gingiva and mandible of a 35-year-old male and the mandible of a 51-year-old female. Given the difficulty in the histopathologic discrimination between benign and malignant smooth muscle tumors and the absence of reliable histologic parameters for prognostication of leiomyosarcomas, we evaluated the diagnostic and prognostic value of various immunohistochemical and molecular markers. By means of immunohistochemistry and quantitative real-time PCR analysis, we detected protein expression of PCNA, bcl-2, CDK4, p53 and MDM2 in both our cases and MDM2 amplification in our second case. The literature, pertinent to oral leiomyosarcoma and to molecular analysis of smooth muscle tumors, is reviewed.

Inflammatory pseudotumor and sarcoma of urinary bladder: differential diagnosis and outcome in thirty-eight spindle cell neoplasms

We assessed diagnostic criteria among 38 spindle cell tumors of the urinary bladder and obtained follow-up in 36 patients. Patients comprised 28 males and 10 females aged 2.5 months to 87 years. Hematuria was the commonest presenting symptom (27 patients). After review and immunohistochemical workup, 17 patients had inflammatory pseudotumor (myofibroblastic tumor), 4 postoperative spindle cell nodule, 1 leiomyoma, 13 sarcoma (7 low-grade; 6 high-grade), and 3 carcinoma. Mean age was 38 years for pseudotumor (range 15 to 74), 65 for postoperative spindle cell nodule, 51 for sarcoma, and 76 for carcinoma. Size of pseudotumor averaged 4.4 +/- 0.7 cm (range 1.5 to 13.0), similar to sarcoma, 4.0 +/- 0.6 cm (range 0.5 to 7.0). Similar proportions of benign tumors and sarcomas had muscularis propria invasion. The criteria that best differentiated sarcoma from inflammatory pseudotumor were presence of necrosis at the tumor-detrusor muscle interface in muscle-invasive cases, and nuclear atypia. Sarcoma also had less prominent microvasculature, less variable cellularity, consistently > or =1 mitotic figure per 10 high-power fields, and predominant acute inflammation without plasma cells. p53 protein nuclear immunostaining was moderate, unlike the rare to absent staining in pseudotumors. Because all 12 sarcomas were desmin-negative, we did not call them leiomyosarcoma; they overlapped with benign tumor in epithelial, mesenchymal, and actin immunostaining. Among 12 sarcoma patients, 2 died of tumor (at 3 months). Two of four experienced tumor recurrence after partial cystectomy (2 and 26 months). No pseudotumors recurred after transurethral resection or partial cystectomy, although one patient, 5 months after transurethral resection, had histologically identical pseudotumor that the surgeon considered residual. Another patient with pseudotumor, not a candidate for tumor ablation after transurethral resection, had continued tumor growth and he died of urosepsis. In conclusion, inflammatory pseudotumor, although overlapping with sarcoma in presentation, age range, and size, does not metastasize and remains histologically distinct from low-grade sarcoma.