Molecular and immunohistochemical evidence for the origin of uterine leiomyosarcomas from associated leiomyoma and symplastic leiomyoma-like areas

Genomic profile analysis of leiomyomas with bizarre nuclei and fumarate hydratase deficient leiomyomas: Strengths, weaknesses, and limitations of array-CGH interpretation

A close relationship has been demonstrated between genomic complexity and clinical outcome in uterine smooth muscle tumors. We studied the genomic profiles by array-CGH of 28 fumarate hydratase deficient leiomyomas and 37 leiomyomas with bizarre nuclei (LMBN) from 64 patients. Follow-up was available for 46 patients (from three to 249 months, mean 87.3 months). All patients were alive without evidence of disease. For 51 array-CGH interpretable tumors the mean Genomic Index (GI) was 16.4 (median: 9.8; from 1 to 57.8), significantly lower than the mean GI in LMS (mean GI 51.8, p < 0.001). We described three groups: (1) a group with FH deletion (24/58) with low GI (mean GI: 11 vs. 22,4, p = 0.02), (2) a group with TP53 deletion (17/58) with higher GI (22.4 vs. 11 p = 0.02), and (3) a group without genomic events on FH or TP53 genes (17/58) (mean GI:18.3; from 1 to 57.8). Because none of these tumors recurred and none showed morphological features of LMS we concluded that GI at the cut-off of 10 was not applicable in these subtypes of LM. By integration of all those findings, a GI <10 in LMBN remains a valuable argument for benignity. Conversely, in LMBN a GI >10 or alteration in tumor suppressor genes, should not alone warrant a diagnosis of malignancy. Nine tumors were tested with Nanocind CINSARC® signature and all were classified in low risk of recurrence. We propose, based on our observations, a diagnostic approach of these challenging lesions.

Benign female genital tract smooth muscle tumors with adipocytic differentiation: A morphologic, immunohistochemical and MDM2 fluorescence in situ hybridization study of 44 conventional lipoleiomyomas and lipoleiomyoma variants

Leiomyomas with adipocytic differentiation typically occur in the uterus although they may arise at several sites in the female genital tract. While these are most commonly spindled leiomyomas with a component of adipocytic tissue ("conventional lipoleiomyomas"), there is a relatively ill-defined assortment of leiomyoma variants with adipocytic differentiation. We performed a morphologic, immunohistochemical and MDM2 gene amplification analysis of a large series of gynecologic leiomyomas with adipocytic differentiation to better define the clinicopathologic spectrum. Forty four tumors from 44 patients were identified and classified as conventional lipoleiomyoma (n = 21), adipocyte-rich lipoleiomyoma (defined as tumor volume >80 % adipocytes, n = 9); cellular lipoleiomyoma (n = 9); hydropic lipoleiomyoma (n = 3); and lipoleiomyoma with bizarre nuclei (n = 2). Patient age ranged from 32 to 83 years (mean 63; median 63). Primary location included uterine corpus (35), uterine cervix (3), uterine corpus/cervix (1), broad ligament (2), parametrium (2), and round ligament (1). Tumor size was 0.6-30 cm (mean 8; median 6). None of the 34 patients with follow up developed further disease (range 1-311 months; mean 65; median 41). Immunohistochemical expression of ER, PR, HMB45, Melan A, Cathepsin K and WT-1 in lipoleiomyomas and variants was similar to patterns in non-adipocytic gynecologic leiomyomas. MDM2 amplification fluorescence in situ hybridization performed on 14 tumors was negative in all. Our findings suggest female genital tract conventional lipoleiomyomas and lipoleiomyoma variants largely parallel their non-adipocytic counterparts in morphology and immunophenotype, and may be categorized using non-adipocytic leiomyoma histologic criteria.

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.

Lipoleiomyomas of the Uterine Cervix: A New Series including the First Recurrent Case and the First Systematic Literature Review

Uterine leiomyomas usually arise from the uterine body (95%), and rarely from the cervix (0.6%) or other urogenital sites. Lipoleiomyomas are benign, uncommon variants of leiomyomas (0.03-0.2%), histologically composed of smooth muscle cells and mature adipocytes; they usually occur in the uterine body and exceptionally in the cervix. We performed the first systematic literature review of cervical lipoleiomyomas (PRISMA guidelines), presenting five new cases. Including our series, thirty-one detailed cases were reported in the literature (mainly in Asia). The age range was 35-74 years, revealing a higher mean age than conventional cervical leiomyomas (46.5 vs. 39.4 years). Patients were usually multiparous (94%), typically complaining of vaginal bleeding (11/31, 36%), pelvic/abdominal pain (10/31, 32%), and/or urinary disturbances (6/31, 19%) 1 week to 10 months before presentation. Clinical examination revealed a pedunculated tumor (48%), or prolapse of ≥1 pelvic organs (16%). Twenty-four (77%) patients underwent total hysterectomy ± additional surgery; simple myomectomy/excision was performed in five (16%) cases. Only one (3%) of our cases recurred 2 years after partial excision; no evidence of disease was found 13 years after recurrence excision. Adipocytes occupied ≤50% of the tumor volume. Hyaline or myxoid changes and cartilaginous metaplasia were uncommon histological findings. Surgically challenging cases or pregnant patients may require expert gynecologists. Interventional radiology or conservative treatments were rarely proposed.

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

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

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.

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

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

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.

A Fast-growing Benign Metastasizing Leiomyoma Mimicking Malignancy

We herein report a rare case of fast-growing benign metastasizing leiomyoma. A 52-year-old woman was admitted to our hospital with abnormal chest shadows. Chest computed tomography showed well-circumscribed cystic tumors. Because malignancy could not be completely distinguished in fast-growing tumors, video-assisted thoracic surgery was performed. The pathological findings revealed many cysts and the proliferation of smooth muscle cells. According to the Stanford criteria, the tumor was diagnosed as benign metastasizing leiomyoma. One possible reason for the fast growth of the tumor was enlargement of the cysts. Malignant diseases characterized by cystic tumors are rare but occasionally reported. Therefore, differentiation by a pathological examination is essential.

The first case of gastric leiomyosarcoma developed through malignant transformation of leiomyoma

Malignant transformation of gastric leiomyoma has not been reported, and therefore it is considered to have virtually no malignant potential. We report a case of gastric leiomyosarcoma arising from leiomyoma. The patient is a 72-year-old man with a submucosal mass measuring 20 mm in diameter, which was incidentally identified by an endoscopic surveillance. A biopsy suggested a diagnosis of leiomyosarcoma, and local excision was performed. Pathological examination revealed that the tumor was composed of two distinct components: typical leiomyoma-like area in the periphery and leiomyosarcoma component exhibiting higher cellularity, prominent nuclear atypia, necrosis, and increased mitosis. Immunohistochemically, in the latter, p53 overexpression, increased Ki-67 labeling index, and attenuated expression of smooth muscle markers were noted. This is the first report to demonstrate the presence of leiomyoma-leiomyosarcoma sequence in the stomach that is well recognized in the uterus. Our observation highlights the potential occurrence of malignant transformation of gastrointestinal leiomyoma.

Current Treatment Options for Cervical Leiomyomas: A Systematic Review of Literature

Background and objectives: Cervical leiomyomas are a rare benign disease. Although they are mainly treated surgically, currently, there is not a standardized treatment for cervical leiomyomas. This study aims to summarize current literature evidence about treatment options for cervical leiomyomas. Materials and methods: A systematic research of the literature was conducted in Scopus, PubMed/MEDLINE, ScienceDirect, and the Cochrane Library, including observational prospective and retrospective studies, case series and case reports. We collected data regarding studies related to treatment options for cervical leiomyomas, evaluating the following aspects: study design, population, treatment type, rate of surgical complications, and fertility outcome. Results: According to literature research, 38 articles were included. Among 214 patients, the weighted average age was 39.4 years-old; 23 patients were pregnant. Most of the leiomyomas (78%) were extracervical; in 22% of cases (29 patients) were intracervical; 188 patients (88%) received surgical treatment, 6 (3%) received exclusive conservative management and 21 (10%) underwent interventional radiology treatment. One hundred twenty-seven patients (67.5%) underwent myomectomy, while 54 (28.7%) and 7 (3.7%) hysterectomy and trachelectomy, respectively. Cervical myomectomy was performed by open surgery in 21 out of 127 cases (16.5%), while in 92 (72.4%) and 6 (4.7%) patients the surgical approach was performed by traditional and robot-assisted laparoscopy, respectively. The total rate of surgical complications was 5.6%. Conclusion: Surgery is the primary therapeutic option for cervical leiomyomas with a low rate of surgical complications. Interventional radiology techniques have reported promising but still limited results.

Differences in gynecologic tumor development in Amhr2-Cre mice with KRASG12D or KRASG12V mutations

How different KRAS variants impact tumor initiation and progression in vivo has not been thoroughly examined. We hypothesize that the ability of either KRAS^G12D or KRAS^G12V mutations to initiate tumor formation is context dependent. Amhr2-Cre mice express Cre recombinase in tissues that develop into the fallopian tubes, uterus, and ovaries. We used these mice to conditionally express either the KRAS^G12V/+or KRAS^G12D/+ mutation. Mice with the genotype Amhr2-Cre Pten^(fl/fl) Kras^G12D/+(G12D mice) had abnormal follicle structures and developed low-grade serous ovarian carcinomas with 100% penetrance within 18 weeks. In contrast, mice with the genotype Amhr2-Cre Pten^(fl/fl) Kras^G12V/+ (G12V mice) had normal follicle structures, and about 90% of them developed uterine tumors with diverse histological features resembling those of leiomyoma and leiomyosarcoma. Granulosa cell tumors also developed in G12V mice. Differences in cell-signaling pathways in the uterine tissues of G12D and G12V mice were identified using RNA sequencing and reverse-phase protein array analyses. We found that CTNNB1, IL1A, IL1B, TNF, TGFB1, APP, and IL6 had the higher activity in G12V mice than in G12D mice. These mouse models will be useful for studying the differences in signaling pathways driven by Kras^G12V/+ or Kras^G12D/+ mutations to aid development of targeted therapies for specific KRAS mutant variants. Our leiomyoma model driven by the Kras^G12V/+ mutation will also be useful in deciphering the malignant progression from leiomyoma to leiomyosarcoma.

Two Rare Cases of Uterine Leiomyosarcomas Originating from Submucosal Leiomyomas Proved by Their Immunohistochemistry Profiles

The most common mesenchymal tumours of the uterine corpus originate from smooth muscle cells. Leiomyomas are commonly found in women of child bearing age; however, leiomyosarcomas occur later in life (50-55 years of age). Most uterine leiomyosarcomas occur de novo, but rare cases of leiomyosarcomas that arise from leiomyomas have been reported. We present two cases of fertile women with submucosal leiomyomas that became malignant and dis- cuss their pathologic features and immunohistochemistry studies for P16, P53 and Ki67.

Reasons to Reconsider Risk Associated With Power Morcellation of Uterine Fibroids

Our insights into the molecular pathogenesis of uterine smooth muscle tumors have improved significantly. Accordingly, in the present review, we advocate a more refined risk assessment for patients considering surgical removal of fibroids or hysterectomy, respectively, requiring morcellation. For this procedure, the risk estimates given for the iatrogenic spread of a previously unexpected malignancy considerably vary among different studies. Nearly all previous studies conducted retrospectively refer to the risk of a patient having an unexpected malignancy at the time of surgery. We feel that, more appropriately, risk should refer to the number of tumors because, as a rule, every single nodule arises independently and, thus, carries an independent risk of being malignant or not. Furthermore, whether so-called parasitic fibroids carry an underestimated risk of stepwise malignant transformation is discussed.

Benign uterine mass-discrimination from leiomyosarcoma by a preoperative risk score: a multicenter cohort study

PURPOSE

Discrimination of uterine leiomyosarcoma (LMS) and leiomyoma (LM) prior to surgery by basic preoperative characteristics and development of a preoperative leiomyosarcoma score.

METHODS

A predominantly prospective cohort of 826 patients with LM from a clinical institution and an outpatient center was included in the study. Further a predominantly retrospective cohort of 293 patients with LMS was included from the counseling database of the German Clinical Center of Excellence for Genital Sarcoma and Mixed Tumors (DKSM, University Medicine Greifswald, Germany). We analyzed and compared anamnestic, epidemiological and clinical findings between both cohorts. Tenfold cross-validated logistic regression and random forest was performed on the 80% training set. The preoperative LMS score (pLMS) was developed based on logistic regression and independently evaluated by analyzing the area under the receiver operating characteristic curve (AUC) with the 20% test set.

RESULTS

In the LMS cohort, 63.1% had initially surgery for presumed LM and only 39.6% of endometrial biopsies revealed LMS. Key features for LMS discrimination were found to be bleeding symptoms: intermenstrual bleeding [RR_c = 2.71, CI = (1.90-3.49), p < 0.001], hypermenorrhea [RR_c = 0.28, CI = (0.15-0.50), p < 0.001], dysmenorrhea [RR_c = 0.22, CI = (0.10-0.51), p < 0.001], postmenstrual bleeding [RR_c = 2.08, CI = (1.30-2.75), p < 0.001], suspicious sonography [RR_c = 1.21, CI = (1.19-1.22), p < 0.001] and the tumor diameter (each centimeter difference: β = 0.24, SD = 0.04, p < 0.001). pLMS achieved a mean cross-validated AUC of 0.969 (SD = 0.019) in the training set and an AUC of 0.968 in the test set.

CONCLUSIONS

The presented score is based on basic clinical characteristics and allows the prediction of LMS prior to a planned surgery of a uterine mass. In case pLMS is between - 3 and + 1, we suggest subsequent diagnostics, such as endometrial biopsy, color Doppler sonography, LDH measurement, MRI and transcervical biopsy.

Exploiting ING2 Epigenetic Modulation as a Therapeutic Opportunity for Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) has been the leading cause of cancer-related death worldwide, over the last few decades. Survival remains extremely poor in the metastatic setting and, consequently, innovative therapeutic strategies are urgently needed. Inhibitor of Growth Gene 2 (ING2) is a core component of the mSin3A/Histone deacetylases complex (HDAC), which controls the chromatin acetylation status and modulates gene transcription. This gene has been characterized as a tumor suppressor gene and its status in cancer has been scarcely explored. In this review, we focused on ING2 and other mSin3A/HDAC member statuses in NSCLC. Taking advantage of existing public databases and known pharmacological properties of HDAC inhibitors, finally, we proposed a therapeutic model based on an ING2 biomarker-guided strategy.

Immunofluorescence analysis of DNA damage response protein p53-binding protein 1 in a case of uterine dedifferentiated leiomyosarcoma arising from leiomyoma

AIMS

Genomic instability has been indicated during the dedifferentiation process from leiomyoma (LM) to leiomyosarcoma (LMS). Previously, we have described that nuclear expression pattern of DNA damage response protein p53-binding protein 1 (53BP1), detected by immunofluorescence, reflects the magnitude of genomic instability during malignancy. Here, we present a case of LMS arising from LM with molecular analysis of 53BP1, which showed transitional magnitude of DNA damage response within a tumor.

METHODS AND RESULTS

A fifty-year-old female with abdominal mass underwent hysterectomy. Histologically, the tumor consisted of LMS with highly atypical multinucleated giant cells as well as an LM component with transitional atypical spindle cells in the border area. LMS showed diffuse nuclear staining of 53BP1 expression, which has been previously described as high DNA damage response pattern. In contrast, the LM component lacked 53BP1 immunoreactivity and focal expression was observed in transitional lesion. Furthermore, double-labelled immunofluorescence revealed co-localization of 53BP1 with p53 and Ki-67 in the LMS component, which indicated abnormal DNA damage response in proliferative state.

CONCLUSIONS

This study revealed that diffuse-type 53BP1 expression may be beneficial to estimate genomic instability during dedifferentiation from LM to DLMS.

Sixteen year-old with leiomyosarcoma in a prior benign myomectomy site

Uterine leiomyosarcoma in a prior myomectomy site is a rare phenomenon. We report an unusual case of a leiomyosarcoma arising six months post myomectomy in a 16-year old female.

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Malignant transformation of a leiomyoma to a leiomyosarcoma is a rare phenomenon.

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Leiomyosarcomas can be extremely aggressive when they present in an adolescence.

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Multidisciplinary team needed to treat an adolescent with a leiomyosarcoma.

Genetic variants and copy number changes in soft tissue leiomyosarcoma detected by targeted amplicon sequencing

Aims

Leiomyosarcomas (LMSs) occur in various tissues and harbour potential for metastases. The genomic landscape of LMS is poorly understood. In an effort to improve understanding of the LMS genome, we analysed 11 LMSs of somatic soft tissue including matching tissue of normal phenotype.

Methods

DNA derived from microdissected tumour domains and matching normal tissue underwent amplicon sequencing of 409 tumour suppressors and oncogenes using the Ion Torrent Comprehensive Cancer Panel.

Results

Genomic changes were heterogeneous with few recurrent abnormalities detected. Coding variants were identified in genes involved in signal transduction, transcriptional regulation and DNA repair. There were variants in several genes related to angiogenesis and GPR124 variants (TEM5) were confirmed by immunohistochemical analysis of a LMS tissue microarray. Surprisingly, there were shared coding variants in tumour and corresponding normal tissue.

Conclusions

LMSs are a very heterogeneous population lacking recurrent somatic abnormalities. The presence of damaging mutations in normal tissue may reflect either a germline predisposition or field effect rather than tissue contamination. Hopeful therapeutic targets appear to be those related to AKT/MTOR pathway.

Case of leiomyosarcoma arising from subserosal leiomyoma

Uterine leiomyosarcoma (LMS) is a rare tumor. It has not been established if these tumors arise de novo or from pre-existing leiomyomas (LM). We report a case herein of LMS arising from a subserosal LM. A 47-year-old nulliparous woman was diagnosed with a uterine tumor measuring 30 cm in diameter by pelvic magnetic resonance imaging. Serum CA-125 level was 369 U/mL, and the lactate dehydrogenase level was elevated (565 IU/L, respectively). Positron emission tomography-computed tomography revealed abnormal uptake (SUV_max = 25.29) of the abdominal tumor. Upon laparotomy, a large tumor with solid and cystic components was shown to arise from a subserosal LM, with invasion into the greater omentum and small intestine. Abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy and small intestine resection were performed. Macroscopic findings showed that the LMS was adherent to a subserosal LM, without continuity between the tumor and the uterus. Our case supports the hypothesis that LMS can arise from a pre-existing LM.

Pleomorphic Undifferentiated Uterine Sarcoma in a Young Patient Presenting With Elevated Beta-hCG and Rare Variants of Benign Leiomyoma: A Case Report and Review of the Literature

Leiomyosarcoma (LMS) is a malignant mesenchymal neoplasm showing smooth muscle differentiation. Uterine LMS is more frequent that nonuterine LMS, and represents 1% of all malignant neoplasms of the uterus. Pleomorphic undifferentiated uterine sarcoma is a rare entity, and is defined by high-grade sarcoma histology with loss of muscular markers. Several cases of pleomorphic undifferentiated uterine sarcoma have been reported in the literature, with worse clinical outcome when compared with conventional LMS. Here we report the first case of a pleomorphic undifferentiated uterine sarcoma in association with LMS in a 33 yr old woman. The patient presented clinically with recurrent vaginal bleeding and suspicion of a trophoblastic tumor. Ancillary testing revealed moderately elevated beta-hCG (49.7 U/L) and no metastatic disease on imaging. Gross examination of the hysterectomy specimen revealed a large heterogenous necrotic uterine mass infiltrating <50% of the myometrium. Microscopic evaluation showed pleomorphic undifferentiated uterine sarcoma adjacent to a nodule of leiomyoma with bizarre nuclei, with loss of myogenic markers in the high grade component. Other findings included a foci of conventional LMS, and diffuse uterine leiomyomatosis. Although beta-hCG dropped to normal levels during follow-up, the patient developed metastatic lesions to the lung at 6 mo postop. Initial elevation of beta-hCG may have correlated with the aggressive histology of the tumor, as reported by some groups previously. Recognition of pleomorphic undifferentiated uterine sarcoma and its distinction from conventional LMS is essential for patient prognosis and management.

Loss of ATRX/DAXX expression and alternative lengthening of telomeres in uterine leiomyomas

BACKGROUND

Uterine leiomyomas (ULs) are the most common gynecologic tumors and affect 3 of every 4 women by the age of 50 years. The majority of ULs are classified as conventional tumors, whereas 10% represent various histopathological subtypes with features that mimic malignancy. These subtypes include cellular and mitotically active ULs and ULs with bizarre nuclei. Uterine leiomyosarcoma (ULMS), the malignant counterpart of UL, is an aggressive cancer with poor overall survival. The early diagnosis and preoperative differentiation of ULMS from UL are often challenging because their symptoms and morphology resemble one another. Recent studies have shown frequent loss of alpha-thalassemia/mental retardation syndrome X-linked (ATRX) or death domain-associated protein (DAXX) expression in ULMS, and this is often associated with an alternative lengthening of telomeres (ALT) phenotype.

METHODS

To investigate ATRX and DAXX expression and the presence of ALT in UL subtypes, immunohistochemical and telomere-specific fluorescence in situ hybridization analyses were performed. The study material consisted of 142 formalin-fixed, paraffin-embedded tissue samples representing various UL subtypes and 64 conventional ULs.

RESULTS

A loss of ATRX or DAXX and/or ALT was detected in 6.3% of the histopathological UL subtype samples (9 of 142). Two patients whose ULs showed either ATRX loss or ALT were later diagnosed with a pulmonary smooth muscle tumor. Pulmonary tumors displayed molecular alterations found in the corresponding uterine tumors, which indicated metastasis to the lungs. All conventional ULs displayed normal ATRX, DAXX, and telomeres.

CONCLUSIONS

These results highlight the differences between conventional and histopathologically atypical ULs and indicate that some UL subtype tumors may harbor long-term malignant potential.

Power morcellation-induced dissemination of sarcomatous component arising in leiomyoma

In 2014, the US Food and Drug Administration issued a safety communication warning against the use of power morcellators during laparoscopic hysterectomy or myomectomy. We report a case of peritoneal leiomyosarcomatosis attributable to power morcellation. A 49-year-old nulligravid woman presented with a huge uterine tumor measuring 15 × 8 cm that was diagnosed as benign leiomyoma on magnetic resonance imaging. The uterine tumor had shrunk to 13 × 7 cm after five treatment courses with a gonadotropin-releasing hormone agonist. She underwent laparoscopic hysterectomy using power morcellation; postoperative pathological diagnosis was benign leiomyoma. After 6 months, urinary ascites developed because of right ureteral rupture. She underwent laparotomy and was diagnosed with peritoneal leiomyosarcomatosis. Meticulous and thorough reevaluation of the morcellated specimens revealed a small component of leiomyosarcoma. Use of power morcellation should be minimized until the advent of novel methods that can perfectly differentiate benign from malignant uterine tumors preoperatively.

Malignant transformation of uterine leiomyoma to myxoid leiomyosarcoma after morcellation associated with ALK rearrangement and loss of 14q

A 50 year old woman underwent laparoscopic supracervical hysterectomy because of symptomatic fibroids. Histologic examination of samples obtained after morcellation revealed typical uterine leiomyomas in all samples investigated. 28 and 47 months later, respectively, the patient presented with peritoneal spreading of nodules that were surgically removed and histologically classified as leiomyosarcoma. In 3/4 of samples obtained after morcellation copy number/SNP-array hybridization showed complex genomic alterations widely identical to the pattern characterizing the sarcoma. Therefore, we conclude that the leiomyosarcoma had unambiguously developed from one of the leiomyomas as a result of secondary genetic alterations i.e. a rearrangement of ALK and a del(14q). The case is challenging the current risk estimates for spreading of unexpected malignant uterine tumors due to power morcellation and highlights the relevance of certain genetic alterations for rare malignant transformation of uterine benign smooth muscle tumors.

Undiagnosed Uterine Sarcomas Identified During Surgery for Presumed Leiomyoma at a National Tertiary Hospital in Thailand: A 10-Year Review

OBJECTIVES

The aim of this study was to evaluate the rate, clinical characteristics, and survival outcomes of an undiagnosed uterine malignancy in patients who underwent surgical treatment for presumed leiomyomas.

METHODS

Medical records of patients who underwent surgical treatment for presumed leiomyomas, from January 2004 to September 2013, were retrospectively reviewed, and the data were followed until September 2016. Demographic data, tumor characteristics, oncologic treatment, and response rate were analyzed by descriptive statistics. Kaplan-Meier method was used for survival analysis. This study includes follow-up data through December 31, 2016.

RESULTS

A total of 11,258 medical records of presumed leiomyoma patients undergoing hysterectomy during the studied period were reviewed. Pathology of uterine sarcoma was found in 22 patients (0.2%), all of whom were included. Nineteen patients had leiomyosarcoma, and 3 had endometrial stromal sarcoma. Mean age of patients was 48.3 ± 6.9 years. All patients underwent total abdominal hysterectomy, with 20 patients undergoing concurrent bilateral salpingo-oophorectomy. Uterine sarcoma was classified as stage IB in 21 patients and stage IIIC in 1 patient. Fifteen patients were prescribed the following adjuvant treatment: chemotherapy in 13 patients and megestrol acetate in 2 patients. Thirteen patients had recurrent disease, and 3 patients died of their disease. The mean progression-free survival was 50.1 ± 41.3 months, and overall survival was 59.3 ± 43.0 months.

CONCLUSIONS

One in 512 patients who underwent hysterectomy because of presumed uterine leiomyomas had inadvertent uterine sarcomas. Even with adjuvant therapy, treatment outcome was rather poor, with almost 60% recurrence rate and median progression-free survival and overall survival of less than 5 years.

Oncomirs Expression Profiling in Uterine Leiomyosarcoma Cells

MicroRNAs (miRNAs) are small non-coding RNAs that act as regulators of gene expression at the post-transcriptional level. They play a key role in several biological processes. Their abnormal expression may lead to malignant cell transformation. This study aimed to evaluate the expression profile of 84 miRNAs involved in tumorigenesis in immortalized cells of myometrium (MM), uterine leiomyoma (ULM), and uterine leiomyosarcoma (ULMS). Specific cell lines were cultured and qRT-PCR was performed. Thirteen miRNAs presented different expression profiles in ULM and the same thirteen in ULMS compared to MM. Eight miRNAs were overexpressed, and five were underexpressed in ULM. In ULMS cells, five miRNAs exhibited an overexpression and eight were down-regulated. Six miRNAs (miR-1-3p, miR-130b-3p, miR-140-5p, miR-202-3p, miR-205-5p, and miR-7-5p) presented a similar expression pattern in cell lines compared to patient samples. Of these, only three miRNAs showed significant expression in ULM (miR-1-3p, miR-140-5p, and miR-7-5p) and ULMS (miR-1-3p, miR-202-3p, and miR-7-5p). Our preliminary approach identified 24 oncomirs with an altered expression profile in ULM and ULMS cells. We identified four differentially expressed miRNAs with the same profile when compared with patients' samples, which strongly interacted with relevant genes, including apoptosis regulator (BCL2), epidermal growth factor receptor (EGFR), vascular endothelial growth factor A (VEGFA), insulin like growth factor 1 receptor (IGF1R),serine/threonine kinase (RAF1), receptor tyrosine kinase (MET), and bHLH transcription factor (MYCN). This led to alterations in their mRNA-target.

Molecular Pathology: Predictive, Prognostic, and Diagnostic Markers in Uterine Tumors

This article focuses on the diagnostic, prognostic, and predictive molecular biomarkers in uterine malignancies, in the context of morphologic diagnoses. The histologic classification of endometrial carcinomas is reviewed first, followed by the description and molecular classification of endometrial epithelial malignancies in the context of histologic classification. Taken together, the molecular and histologic classifications help clinicians to approach troublesome areas encountered in clinical practice and evaluate the utility of molecular alterations in the diagnosis and subclassification of endometrial carcinomas. Putative prognostic markers are reviewed. The use of molecular alterations and surrogate immunohistochemistry as prognostic and predictive markers is also discussed.

Two Subtypes of Atypical Leiomyoma: Clinical, Histologic, and Molecular Analysis

Atypical leiomyoma (ALM) is a rare variant of uterine smooth muscle tumors. Several recent studies have suggested that ALM has distinct, but also heterogenous, histologic and molecular features, yet little is known about the biology and histogenesis of ALM. Some have even postulated whether the atypical histologic features represent true atypia or simply degenerative changes. In this study, we analyzed the cytologic features of 60 ALM cases and found that ALM could be further divided into 2 subtypes, type I and type II, based primarily on nuclear features. Type I ALM showed round or oval nuclei, distinct and smooth nuclear membranes, prominent nucleoli with perinucleolar halos, and open coarse chromatin. Type II ALM showed elongated or spindled nuclei, irregular nuclear membranes, pinpoint or no nucleoli, and dark smudgy chromatin. There were also architectural differences between type I and type II ALM. Type I ALM often showed diffuse atypia within the tumor, whereas the atypia in type II ALM was patchy, surrounded by usual-type leiomyoma. The 2 subtypes also differed when we compared the immunohistochemical and molecular patterns. Type II tumors showed significantly higher rates of immunoreactivity for p16, p53, and HMGA2 and showed MED12 mutations more frequently than the type I counterparts. Our findings suggest that the type I and type II subtypes of ALM may arise from 2 different pathways. Type I tumors may be related to fumarate hydratase mutations, whereas type II ALM appear to arise in a existing usual-type leiomyomas.

Characterization of MED12, HMGA2, and FH alterations reveals molecular variability in uterine smooth muscle tumors

Uterine smooth muscle tumors range from benign leiomyomas to malignant leiomyosarcomas. Based on numerous molecular studies, leiomyomas and leiomyosarcomas mostly lack shared mutations and the majority of tumors are believed to develop through distinct mechanisms. To further characterize the molecular variability among uterine smooth muscle tumors, and simultaneously insinuate their potential malignant progression, we examined the frequency of known genetic leiomyoma driver alterations (MED12 mutations, HMGA2 overexpression, biallelic FH inactivation) in 65 conventional leiomyomas, 94 histopathological leiomyoma variants (18 leiomyomas with bizarre nuclei, 22 cellular, 29 highly cellular, and 25 mitotically active leiomyomas), and 51 leiomyosarcomas. Of the 210 tumors analyzed, 107 had mutations in one of the three driver genes. No tumor had more than one mutation confirming that all alterations are mutually exclusive. MED12 mutations were the most common alterations in conventional and mitotically active leiomyomas and leiomyosarcomas, while leiomyomas with bizarre nuclei were most often FH deficient and cellular tumors showed frequent HMGA2 overexpression. Highly cellular leiomyomas displayed the least amount of alterations leaving the majority of tumors with no known driver aberration. Our results indicate that based on the molecular background, histopathological leiomyoma subtypes do not only differ from conventional leiomyomas, but also from each other. The presence of leiomyoma driver alterations in nearly one third of leiomyosarcomas suggests that some tumors arise through leiomyoma precursor lesion or that these mutations provide growth advantage also to highly aggressive cancers. It is clinically relevant to understand the molecular background of various smooth muscle tumor subtypes, as it may lead to improved diagnosis and personalized treatments in the future.

Exploring chromosomal abnormalities and genetic changes in uterine smooth muscle tumors

Smooth muscle tumors of the uterus are a diagnostically challenging group of tumors. Molecular surrogate markers reliably distinguishing between benign and malignant tumors are not available. Therefore, the diagnosis is based on morphologic criteria. The aim was to investigate a well-characterized group of challenging uterine smooth muscle tumors consisting of 20 leiomyomas, 13 leiomyomas with bizarre nuclei, and 14 leiomyosarcomas for copy number alterations, MED12 mutations and FH deletions to search for potential diagnostically useful surrogate markers. MED12 mutations were detected in 47, 15, and 25% of leiomyomas, leiomyomas with bizarre nuclei and leiomyosarcomas, respectively. MED12 mutations in leiomyomas with bizarre nuclei were detected outside the hotspot region. FH-deletions were seen in 27, 30.8, and 25% of leiomyomas, leiomyomas with bizarre nuclei and leiomyosarcomas, respectively. By using copy number alteration profiling a clear separation of leiomyomas, leiomyomas with bizarre nuclei and leiomyosarcomas could not be observed. Copy number alterations revealed clear genetic similarities between leiomyomas with bizarre nuclei and leiomyosarcomas. Leiomyosarcomas showed a similar pattern of gains and losses as leiomyomas with bizarre nuclei, with additional copy number alterations and more homozygous losses and high-level amplifications compared to leiomyomas with bizarre nuclei. In conclusion, this study demonstrates that known FH-deletions, a recurrent molecular change in leiomyomas, occur in morphologically challenging variants of leiomyomas, leiomyomas with bizarre nuclei and leiomyosarcomas. Although MED12 mutations are common in leiomyomas, they infrequently occur in leiomyomas with bizarre nuclei and leiomyosarcomas. The genetic similarities between leiomyomas with bizarre nuclei and leiomyosarcomas raise the intriguing possibility that uterine leiomyomas with bizarre nuclei and leiomyosarcomas are closely related and challenge the traditional concept that leiomyoma with bizarre nuclei is a tumor with just marked 'degenerative' cellular changes. These findings support the hypothesis that tumor progression within uterine smooth muscle tumors might occur.

Identification of uterine leiomyoma-specific marker genes based on DNA methylation and their clinical application

Differential diagnosis of uterine leiomyomas and leiomyosarcomas is needed to determine whether the uterus can be retained. Therefore, biomarkers for uterine leiomyomas, and reliable and objective diagnostic methods have been desired besides the pathological diagnosis. In the present study, we identified 12 genes specific to uterine leiomyomas based on DNA methylation. Using these marker genes specific to uterine leiomyomas, we established a hierarchical clustering system based on the DNA methylation level of the marker genes, which could completely differentiate between uterine leiomyomas and normal myometrium. Furthermore, our hierarchical clustering system completely discriminated uterine cancers and differentiated between uterine leiomyosarcomas and leiomyomas with more than 70% accuracy. In conclusion, this study identified DNA methylation-based marker genes specific to uterine leiomyomas, and our hierarchical clustering system using these marker genes was useful for differential diagnosis of uterine leiomyomas and leiomyosarcomas.

Current Chemotherapy and Potential New Targets in Uterine Leiomyosarcoma

A variety of chemotherapeutic agents have been used for treating recurrent or advanced stage uterine leiomyosarcoma (ULMS). The response rates of these current agents are disappointing, with partial response rates varying from 0% to 33%, and complete response rates varying from 0% to 8%. Recent studies have documented many molecular changes in ULMSs. Prominent amongst these are gains of growth factors C-MYC, Bcl-2, K-ras, and Ki-67, and losses in tumor suppressors p16, p53, Rb1, ING2 and D14S267. Various techniques that have been used to target these molecules are presented. Targeting specific therapies at these underlying molecular changes could potentially yield better response rates with fewer side effects.

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.

Clonally related uterine leiomyomas are common and display branched tumor evolution

Uterine leiomyomas are extremely frequent benign smooth muscle tumors often presenting as multiple concurrent lesions and causing symptoms such as abnormal menstrual bleeding, abdominal pain and infertility. While most leiomyomas are believed to arise independently, a few studies have encountered separate lesions harboring identical genetic changes, suggesting a common clonal origin. To investigate the frequency of clonally related leiomyomas, genome-wide tools need to be utilized, and thus little is known about this phenomenon. Using MED12 sequencing and SNP arrays, we searched for clonally related uterine leiomyomas in a set of 103 tumors from 14 consecutive patients who entered hysterectomy owing to symptomatic lesions. Whole-genome sequencing was also utilized to study the genomic architecture of clonally related tumors. This revealed four patients to have two or more tumors that were clonally related, all of which lacked MED12 mutations. Furthermore, some tumors were composed of genetically distinct subclones, indicating a nonlinear, branched model of tumor evolution. DEPDC5 was discovered as a novel tumor suppressor gene playing a role in the progression of uterine leiomyomas. Perhaps counterintuitively—considering Knudson's two-hit hypothesis—a large shared deletion was followed by different truncating DEPDC5 mutations in four clonally related leiomyomas. This study provides insight into the intratumor heterogeneity of these tumors and suggests that a shared clonal origin is a common feature of leiomyomas that do not carry an MED12 mutation. These observations also offer one explanation to the common occurrence of multiple concurrent lesions.

Endometriosis, leiomyoma and adenomyosis: the risk of gynecologic malignancy

The aim of this review article was to evaluate the relationship and the possible etiological mechanisms between endometriosis, leiomyoma (LM) and adenomyosis and gynecological cancers, such as ovarian and endometrial cancer and leiomyosarcoma (LMS). MEDLINE was searched for all articles written in the English literature from July 1966 to May 2013. Reports were collected systematically and all the references were also reviewed. Malignant transformation of gynecologic benign diseases such as endometriosis, adenomyosis and LM to ovarian and endometrial cancer remains unclear. Hormonal factors, inflammation, familial predisposition, genetic alterations, growth factors, diet, altered immune system, environmental factors and oxidative stress may be causative factors in carcinogenesis. Early menarche, low parity, late menopause and infertility have also been implicated in the pathogenesis of these cancers. Ovarian cancers and endometriosis have been shown to have common genetic alterations such as loss of heterozygosity (LOH), PTEN, p53, ARID1A mutations. MicroRNAs have also been implicated in malignant transformation. Inflammation releases proinflammatory cytokines, and activates tumor associated macrophages (TAMS) and nuclear factor kappa b (NF-KB) signaling pathways that promote genetic mutations and carcinogenesis. MED12 mutations in LM and smooth muscle tumors of undetermined malignant potential (STUMP) may contribute to malignant transformation to LMS. A hyperestrogenic state may be shared in common with pathogenesis of adenomyosis, LM and endometrial cancer. However, the effect of these benign gynecologic diseases on endometrial cancer should be studied in detail. This review study indicates that endometriosis, LM, adenomyosis may be associated with increased risk of gynecological cancers such as endometrial and ovarian cancers. The patients who have these gynecological benign diseases should be counseled about the future risks of developing cancer. Further studies are needed to investigate the relationship between STUMPs, LMS and LM and characteristics and outcome endometrial carcinoma in adenomyotic patients.

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."

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.