h-Caldesmon, a novel smooth muscle-specific antibody, distinguishes between cellular leiomyoma and endometrial stromal sarcoma

Immunohistochemical analysis of 147 cases of low-grade endometrial stromal sarcoma: refining the immunohistochemical profile of LG-ESS on a large, molecularly confirmed series

Low-grade endometrial stromal sarcoma (LG-ESS) can present diagnostic challenges, due to its overlapping morphological features with other uterine mesenchymal tumors. Misdiagnosis rates remain significant, and immunohistochemical data for LG-ESS are limited to small series and inconsistent antibody panels. This study aimed to refine the IHC profile of LG-ESS by analyzing a large, molecularly confirmed series of 147 cases using a panel of 24 antibodies, including newer markers like transgelin and smoothelin. CD10 and IFITM1, key endometrial stromal markers, were expressed in 86% (92% of those extensively) and 69% (60% of those extensively) of cases, with fusion-positive tumors showing significantly higher expression. Smooth muscle markers (α-SMA, desmin, h-caldesmon, calponin, transgelin) were variably expressed, predominantly in focal or low-intensity patterns, with α-SMA reaching the highest frequency of expression (44%). However, the intensity of smooth muscle marker expression was usually very low. Smoothelin was rarely expressed. Hormone receptors were frequently positive, with PR showing a higher frequency (92% vs. 83%) and intensity than ER. Markers like S-100, HMB45, and CD117 were largely negative; all tumors were p53 wild-type, with preserved SMARCB1/SMARCA4 expression and ALK and ROS1 negativity. This work represents the largest molecularly validated IHC study on LG-ESS, providing a robust diagnostic profile for routine pathology. By addressing key diagnostic limitations and examining newer markers, our study supports a more standardized approach to diagnosing LG-ESS and underscores the value of immunohistochemical panels, particularly in fusion-negative tumors where diagnosis relies on morphological and immunohistochemical interpretation. These findings contribute critical data for improving diagnostic accuracy.

Immunohistochemical Expression of Lymphoid Enhancer-binding Factor 1 in Low-grade Endometrial Stromal Tumors

Endometrial stromal tumors (ESTs) are uncommon uterine mesenchymal lesions. Nuclear expression of β-catenin, an indication of activated Wnt/β-catenin signaling pathway, was described in 50% to 92% of low-grade ESTs, including endometrial stromal nodule and low-grade endometrial stromal sarcoma. Activation of the Wnt/β-catenin signaling pathway leads to the translocation of β-catenin into the nucleus and interaction with the T-cell factor/lymphoid enhancer-binding factor-1 (LEF1) family of transcription factors to regulate cell proliferation, differentiation, migration, and survival. Immunohistochemical analysis of β-catenin and LEF1 was performed in 2 endometrial stromal nodules and 20 low-grade endometrial stromal sarcomas and demonstrated 90.9% and 81.8% positive rates for β-catenin and LEF1, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value of β-catenin and LEF1 were 90.9% versus 81.8%, 81.0% versus 85.7%, 83.3% versus 85.7%, 89.5% versus 81.8%, respectively, in the diagnosis of low-grade ESTs. There is no statistical significance of the performance of β-catenin and LEF1 in all ESTs ( P = 0.664) or in primary or metastatic/recurrent settings ( P = 0.515 and 0.999, respectively). Only 3 smooth muscle tumors showed focal and weak positivity for LEF1. Our results indicate LEF1 can be a useful marker in aiding a diagnosis of low-grade EST and differentiating from smooth muscle tumors alone or in combination with β-catenin.

An Extremely Rare Case of Disseminated Peritoneal Leiomyomatosis with a Pelvic Leiomyosarcoma and Omental Metastasis after Laparoscopic Morcellation: Systematic Review of the Literature

Minimally invasive treatment of uterine fibroids usually requires a power morcellation, which could be associated with several complications. A rare sequela is disseminated peritoneal leiomyomatosis. Indeed, recurrence or metastasis in these cases could be attributed to iatrogenic or under-evaluation of primary tumors, although a subset of cases is a sporadic sample of biological progression. We present an extremely rare case of a patient who underwent laparoscopic morcellation and after 12 years developed a pelvic leiomyosarcoma with two omental metastases, disseminated peritoneal leiomyomatosis with a parasite leiomyoma with bizarre nuclei and a parasite cellular leiomyoma simultaneously. The diagnosis was predicted preoperatively by an expert sonographer who recognized the ultrasound characteristics of uterine sarcoma and the localization of some of the masses, so the patient was referred to the gynaecological oncologists who could appropriately treat her. We present here a case report and a systematic review that could be a useful tool for further discussion and future clinical practice guidelines.

Uterine cellular leiomyomas are characterized by common HMGA2 aberrations, followed by chromosome 1p deletion and MED12 mutation: morphological, molecular, and immunohistochemical study of 52 cases

Cellular leiomyoma (CL) represents an uncommon variant of uterine leiomyoma with limited data concerning its immunohistochemical and molecular profile. We performed a comprehensive analysis of 52 CL cases all of which were analyzed immunohistochemically. Molecular analysis was possible in 32 cases with sufficient DNA, and 38 cases with sufficient RNA. The immunohistochemical results showed a high expression of smooth muscle markers (calponin (100%), desmin (100%), smooth muscle actin (98.1%), caldesmon (96.1%), transgelin (96.1%), smooth muscle myosin heavy chain (86.5%), and smoothelin (61.5%)). Concerning markers of endometrial stromal differentiation, the expression of CD10 was observed in 65.4% cases (42.2% with H-score > 50), and IFITM1 in 36.5% cases (1.9% with H-score > 50). 36.5% showed HMGA2 overexpression at the IHC level, associated with increased mRNA expression in 14/14 cases. The rearrangement of the HMGA2 gene was detected in 13.2%. Chromosome 1p deletion was found in 19.3%, while 9.4% of tumors showed a pathogenic mutation in the MED12 gene. In conclusion, CL is immunohistochemically characterized by a high expression of "smooth muscle" markers commonly associated with a co-expression of "endometrial stromal" markers, where IFITM1 shows superior performance compared to CD10 regarding its specificity for differentiation from endometrial stromal tumors. The sensitivity of smoothelin in CL seems rather low, but no data is available to assess its specificity. On a molecular level, the most common mutually exclusive aberration in CL affects HMGA2, followed by chromosome 1p deletions and MED12 mutations.

IFITM1, CD10, SMA, and h-caldesmon as a helpful combination in differential diagnosis between endometrial stromal tumor and cellular leiomyoma

Background

The differential diagnosis of endometrial stromal tumor (EST) and uterine cellular leiomyoma (CL) remains a challenge in clinical practice, especially low grade endometrial stromal sarcoma (ESS) and CL, suggesting the need for novel immunomarkers panels for differential diagnosis. Interferon-induced transmembrane protein 1 (IFITM1) is a novel immunomarker for endometrial stromal cells, h-caldesmon is an immunomarker for smooth muscle cells and has a higher specificity than smooth muscle actin (SMA). So this study aimed to evaluate whether IFITM1, cluster of differentiation 10(CD10), SMA, and h-caldesmon are useful biomarker combinations for the differential diagnosis of EST and CL.

Methods

Tissue microarrays were used to detect IFITM1, CD10, SMA, and h-caldesmon immunohistochemical staining in 30 EST and 33 CL cases.

Results

The expressions of IFITM1 and CD10 were high in EST (86.7 and 63.3%, respectively) but low in CL (18.2 and 21.2%), whereas those of h-caldesmon and SMA were high in CL (87.9 and 100%) and low in EST (6.9 and 40%). In diagnosing EST, IFITM1 shows better sensitivity and specificity (86.7 and 81.8%, respectively) than CD10 (63.3 and 78.8%). The specificity of h-caldesmon in diagnosing CL was significantly higher (93.1%) than that of SMA (60%). When all four antibodies were combined for the differential diagnosis, the area-under-the-curve (AUC) predictive value was 0.995. The best combination for diagnosing EST was IFITM1 (+) or CD10 (+) and h-caldesmon (−) (sensitivity 86.7%, specificity 93.9%).

Conclusion

The best combination for diagnosing CL were h-caldesmon (+) and SMA (+) (sensitivity 87.9%, specificity 100%). IFITM1, CD10, SMA, and h-caldesmon are a good combination for the differential diagnosis of EST and CL.

Caldesmon: Biochemical and Clinical Implications in Cancer

Caldesmon, an actin-binding protein, can inhibit myosin binding to actin and regulate smooth muscle contraction and relaxation. However, caldesmon has recently attracted attention due to its importance in cancer. The upregulation of caldesmon in several solid cancer tissues has been reported. Caldesmon, as well as its two isoforms, is considered as a biomarker for cancer and a potent suppressor of cancer cell invasion by regulating podosome/invadopodium formation. Therefore, caldesmon may be a promising therapeutic target for diseases such as cancer. Here, we review new studies on the gene transcription, isoform structure, expression, and phosphorylation regulation of caldesmon and discuss its clinical implications in cancer.

Primary Gastrointestinal Stromal Tumor of the Prostate: Unexpected Guest

Primary mesenchymal lesions of the prostate are exceptionally rare. They comprise 1% of all prostatic neoplasms. Despite its rare location, the diagnosis of primary gastrointestinal stromal tumors (GISTs) of the prostate gland should never be missed. Such a diagnosis can be made after the rolling out of direct extension from adjacent organs, especially the rectum. GIST diagnosis has a clinical impact on patient treatment and clinical outcomes. They harbor a certain KIT activation mutation that responds to pharmacologic therapy inhibitors.

The objective of the current study was to provide a thorough review of GIST arising primarily in the prostate gland along with a comprehensive study of GIST pathogenesis, histologic morphology, immunohistochemistry, and molecular studies’ findings, and their importance in differentiating GIST from other prostate mesenchymal tumors. This will emphasize the role of careful spindle cell lesion diagnosis in the prostate gland that can influence the prognostic stratification of clinical management, future follow-up, and disease outcome.

Thirteen cases were collected after an extensive and detailed review of the English literature through PubMed, Medknow, Google Scholar, as well as personal experience.

The anatomic location of this lesion plays a significant role in the differential diagnosis. It is difficult to establish the accurate primary origin of GIST on core needle tissue biopsy. Thus, clinical, and radiological examinations play a crucial role in rolling out the possibility of rectal GIST secondarily invading and involving the prostate gland.

To conclude, primary prostatic GIST is a rare diagnosis. Extraintestinal, particularly rectal, GIST can clinically and radiologically mimic the impression of the prostatic lesion. Before diagnosing primary prostatic spindle cell lesions, such as solitary fibrous tumor (SFT), inflammatory myofibroblastic tumor (IMT), leiomyoma, leiomyosarcoma, or prostatic stromal tumors, one should include CD117/c-Kit in the workup of a prostatic spindle cell lesion. GIST has distinct pathogenesis, and its diagnosis can have a clinical impact on the patient's management plan and clinical outcome.

Gene fusions characterize a subset of uterine cellular leiomyomas

Uterine leiomyomas are the most common benign tumor of the female genital tract. Previous studies have shown that conventional leiomyomas often harbor-specific alterations including rearrangements involving HMGA2. Cellular leiomyomas are a variant of uterine leiomyoma that are less well-studied from a genomic point of view. Morphologically and immunohistochemically, cellular leiomyomas may be confused with low-grade endometrial stromal neoplasms, a group of tumors which frequently harbor a number of recurrent gene fusions. Ancillary molecular testing may be used to investigate tumors where low-grade endometrial stromal neoplasms enter into the differential diagnosis. At our institution, we identified a uterine cellular leiomyoma harboring a HMGA2-TRAF3IP2 fusion. After a retrospective review 11 additional tumors were identified. All included cases were reviewed and evaluated for immunohistochemical expression of smooth muscle actin, desmin, h-caldesmon, CD10, estrogen receptor, and progesterone receptor. RNA sequencing using the TruSight RNA Fusion Panel was performed on formalin-fixed paraffin-embedded tissue samples. In addition to the index case, two other cases harbored fusions: HMGA2-NAA11 and TPCN2-YAP1, of which the latter is novel and was confirmed with reverse transcriptase-polymerase chain reaction. In conclusion, a subset of cellular leiomyomas harbor rearrangements involving HMGA2, suggesting molecular kinship with conventional uterine leiomyomas. In addition, the prevalence of the novel TPCN2-YAP1 gene fusion in cellular leiomyomas requires further study. The fusions reported here, when identified, may be useful when the diagnosis of cellular leiomyoma is in question.

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.

Beyond Smooth Muscle-Other Mesenchymal Neoplasms of the Uterus

Mesenchymal tumors of the uterus comprise a heterogeneous group of neoplasms of varied biologic potential. In addition to being host to several anatomically unique entities, the uterus may contain mesenchymal neoplasms typically found elsewhere in the body. Although smooth muscle neoplasms are common, other mesenchymal neoplasms in this location are relatively rare. Many of these neoplasms exhibit morphologic overlap. In addition to a careful histomorphologic review, definitive classification frequently depends on the judicious application of ancillary immunohistochemical and molecular testing. The intent of this review is to offer a basic approach to the classification of primary uterine mesenchymal neoplasms.

Magnetic resonance imaging features of uterine sarcoma and mimickers

Uterine myometrial tumors are predominantly benign conditions that affect one-third of women and represent the main indication for hysterectomy. Preoperative imaging is of utmost importance for characterization and for precise mapping of myometrial tumors to best guide therapeutic strategy. New minimally invasive therapeutic strategies including morcellation, myolysis, uterine artery embolization and image-guided radiofrequency or focused ultrasound ablation have been developed for the treatment of uterine leiomyoma. However, preoperative differentiation between atypical leiomyomas and leiomyosarcomas is critical on imaging as uterine sarcoma requires a specific surgical technique to prevent dissemination. A single, rapidly growing uterine tumor, associated with endometrial thickening and ascites, in post-menopausal women is suspicious of uterine endometrial stromal sarcoma and carcinosarcoma. Suggestive magnetic resonance imaging features have been described, but overlap in imaging appearance between uterine leiomyosarcomas and cellular leiomyomas makes it challenging to ascertain the diagnosis. This review aims to illustrate the imaging features of uterine sarcomas and potential mimickers to make the reader more familiar with this serious condition which needs special consideration.

Analysis of HSP90 Expression Is Valuable in the Differential Diagnosis of Ocular Surface Squamous Lesions

OBJECTIVES

The aim of this study was to evaluate heat shock protein 90 (HSP90) expression in squamous lesions (SLs) and to assess its diagnostic value for different lesions within the SL spectrum.

METHODS

A total of 70 conjunctival SLs, including 19 papillomas, 22 cases of conjunctival intraepithelial neoplasia (ConINs) I, 11 cases of ConIN II, six cases of ConIN III, and 12 squamous carcinomas (sqCAs), were evaluated using the German immunoreactive score against HSP90.

RESULTS

Cytoplasmic HSP90 expression differed between low- and high-grade lesions (P < .001). Among high-grade lesions, the nuclear HSP90 score was higher in the ConIN III-sqCA group than in the ConIN II group (P = .0162). A percentage of total thickness staining of less than 73% differentiated between ConIN III and sqCA.

CONCLUSIONS

The expression of HSP90 is particularly useful to differentiate low-grade from high-grade lesions of the conjunctiva. HSP90 may play an important role in the malignant transformation of SLs and could be a new target for therapy.

Practical issues related to uterine pathology: endometrial stromal tumors

Uterine mesenchymal tumors continue to be a challenge to diagnose due to their non-specific clinical presentation, often non-distinctive gross appearance, varied (and many times overlapping) morphologic appearance, and unsuspected pitfalls in immunohistochemical expression. This review will focus on endometrial stromal tumors and those features that help in their distinction. In particular, a practical approach to the diagnosis of endometrial stromal neoplasia will be covered including recognition as a stromal process in a biopsy/curettage and distinction from a highly cellular leiomyoma. In addition, distinction of a stromal nodule from a low-grade endometrial stromal sarcoma (LGESS) and stromal sarcoma with limited infiltration in a hysterectomy specimen will be covered. The salient features that help distinguish a LGESS from a uterine tumor resembling ovarian sex-cord tumor as well as high-grade endometrial stromal sarcoma, the latter a tumor recently reintroduced in the WHO classification will also be discussed. Finally, a practical approach to the diagnosis of undifferentiated uterine sarcoma (UUS) will be presented.

SIRT2 Expression Is Higher in Uveal Melanoma than In Ocular Melanocytes

PURPOSE

Sirtuins (SIRTs) are the family of proteins associated with the cell cycle and that correlate with cancer development and progression. SIRTs have never been studied in uveal melanocytes. The aim of this study is to characterize the expression of SIRT2 in uveal melanoma (UM) cases and compare it with the expression of SIRT2 in melanocytes of the uveal tract of normal human eyes (NHE).

METHODS

Twenty-one formalin-fixed, paraffin-embedded human UM cases were immunostained for SIRT2, along with 15 NHE obtained from the Eye Bank of Canada.

RESULTS

SIRT2 expression was higher in melanomas than in normal melanocytes of both tumor and donor eyes (p < 0.0001). No significant difference in SIRT2 expression was found when comparing normal melanocytes in UM and NHE cases.

CONCLUSIONS

SIRT2 expression is significantly stronger in UM cells than in normal ocular melanocytes. This finding may indicate an important role of SIRT2 as a prognostic marker in UM progression. SIRT2 should also be investigated as a possible therapeutic target.

Testicular orphan nuclear receptor 4 is associated with the radio-sensitivity of prostate cancer

BACKGROUND

It is well known that a significant number of prostate cancers (PCa) showed different extents of radio-resistance and the tumor may recur after treatment. Recent studies demonstrated that Testicular orphan nuclear receptor 4 (TR4) could play a critical role in anti-oxidative stress responses and might modulate the DNA damage repair. The objective of this study is to investigate the role of TR4 in the radiotherapy for PCa.

METHODS

The TR4 expression in tissue samples from PCa patients treated with brachytherapy was measured by immunohistochemistry (IHC). Cell survival test and colony formation assay were applied to test the radio-sensitivity of PCa cells with modulated TR4 gene expression upon irradiation.

RESULTS

PCa patients with biochemical recurrence (BCR) after brachytherapy tend to have higher TR4 expression (80%, n = 30) as compared to those without BCR (36.67%, n = 30). Survival analysis demonstrated a significant higher BCR occurrence in patients with high level of TR4 expression (HR = 3.474, 95%CI 1.678-7.192, P = 0.0008). Multivariate analysis showed that the TR4 staining score on IHC was the only significant variable for predicting the PCa patients' clinical outcomes after radiotherapy (OR = 9.919, 95% CI 2.516-39.101, P = 0.001). Using cell survival test and colony forming assay, we found that the addition of functional TR4 in PC3 cells lead to elevated radio-resistance. In contrast, knocking-down TR4 in LNCaP cells resulted in increased radio-sensitivity. The γH2AX foci kinetic analysis suggested that knocking down TR4 might delay the PCa cell's DNA damage repair which would enhance the radio-sensitivity.

CONCLUSION

TR4 could mediate the PCa cells' radio-sensitivity and might become a prognostic indicator for PCa patients received radiotherapy. This study provides a novel approach to manipulate radio-sensitivity of PCa cells, and may bring a promoted therapeutic outcome of radiotherapy to battle PCa in future.

Immunohistochemical panel to differentiate endometrial stromal sarcoma, uterine leiomyosarcoma and leiomyoma: something old and something new

AIMS

To evaluate an immunohistochemical panel differentiating endometrial stromal sarcoma (ESS) from uterine leiomyosarcoma (ULMS) and leiomyoma (LM).

METHODS

94 cases (28 ESS, 41 ULMS, 25 LM) were retrieved and arrayed. 10 immunomarkers (estrogen receptor (ER), progesterone receptor (PR), CD10, smooth muscle actin, desmin, h-caldesmon, transgelin, GEM, ASC1, stathmin1) were used. A predictive model was constructed and examined by receiver operating characteristics curve analysis to determine area under the curve (AUC).

RESULTS

The combination of ER(+)/PR(+)/CD10(+)/GEM(-)/h-caldesmon(-)/transgelin(-) can predict ESS versus ULMS with AUC predictive value of 0.872 (95% CI 0.784 to 0.961, p<0.0001). The combination of ER(+)/PR(+)/CD10(+)/h-caldesmon(-)/transgelin(-) can predict low grade (LG) ESS from 'LG' ULMS with AUC predictive value of 0.914 (95% CI 0.832 to 0.995, p<0.0001). Finally, ULMS and ESS, including the LGs, were more likely to be stathmin1(+) than LM.

CONCLUSIONS

Due to the different clinical course and management, adding novel antibodies (GEM, transgelin) to the well established immunohistochemistry panel seemed to be useful in distinguishing ESS from ULMS and LG ESS from 'LG' ULMS. Finally, stathmin1 expression could be of value in differentiating LM from uterine sarcomas.

Endometrial stromal tumours revisited: an update based on the 2014 WHO classification

Endometrial stromal tumours (EST) are rare tumours of endometrial stromal origin that account for less than 2% of all uterine tumours. Recent cytogenetic and molecular advances in this area have improved our understanding of ESTs and helped refine their classification into more meaningful categories. Accordingly, the newly released 2014 WHO classification system recognises four categories: endometrial stromal nodule (ESN), low-grade endometrial stromal sarcoma (LGESS), high-grade endometrial stromal sarcoma (HGESS) and undifferentiated uterine sarcoma (UUS). At the molecular level, these tumours may demonstrate a relatively simple karyotype with a defining chromosomal rearrangement (as in the majority of ESNs, LGESSs and YWHAE-rearranged HGESS) or demonstrate complex cytogenetic aberrations lacking specific rearrangements (as in UUSs). Herein we provide an update on this topic aimed at the practicing pathologist.

Targeted development of specific biomarkers of endometrial stromal cell differentiation using bioinformatics: the IFITM1 model

When classifying cellular uterine mesenchymal neoplasms, histological distinction of endometrial stromal from smooth muscle neoplasms can be difficult. The only widely established marker of endometrial stromal differentiation, CD10, has marginal specificity. We took a bioinformatics approach to identify more specific markers of endometrial stromal differentiation by searching the Human Protein Atlas, a public database of protein expression profiles. After screening the database using different methods, interferon-induced transmembrane protein 1 (IFITM1) was selected for further analysis. Immunohistochemistry for IFITM1 was performed using tissue sections from the selected cases of proliferative endometrium (22), secretory endometrium (6), inactive endometrium (19), adenomyosis (10), conventional leiomyoma (11), cellular leiomyoma (16), endometrial stromal nodule (2), low-grade endometrial stromal sarcoma (16), high-grade endometrial stromal sarcoma (2) and undifferentiated uterine sarcoma (2). Stained slides were scored in terms of intensity and distribution. Normal endometrial samples uniformly showed diffuse and strong IFITM1 staining. Endometrial stromal neoplasms, particularly low-grade endometrial stromal sarcoma, showed higher IFITM1 expression compared with smooth muscle neoplasms (P<0.0001). IFITM1 immunohistochemistry has high sensitivity and specificity, particularly in the distinction between low-grade endometrial stromal sarcoma and leiomyoma (81.2 and 86.7%, respectively). Our results indicate that IFITM1 is a sensitive and specific marker of endometrial stromal differentiation across the spectrum from proliferative endometrium to metastatic stromal sarcoma. IFITM1 is a potential valuable addition to immunohistochemical panels used in the diagnosis of cellular mesenchymal uterine tumors. Further studies with larger number of cases are necessary to corroborate this impression and determine the utility of IFITM1 in routine practice. This study is a clear example of how bioinformatics, particularly tools for mining genomic and proteomic databases, can enhance and accelerate biomarker development in diagnostic pathology.

Adenomyomatous Polyp of the Endometrium With Prominent Epithelioid Smooth Muscle Differentiation

A minor component of smooth muscle may be present in the stroma of benign endometrial polyps and 2 distinctive endometrial polypoid lesions, atypical polypoid adenomyoma and adenomyoma, are characterized by stroma with a predominant smooth muscle component. In this report, we describe 2 unusual endometrial polyps in 43- and 60-year-old women in which the stromal component was predominantly composed of smooth muscle with an epithelioid appearance, a phenomenon which, as far as we are aware, has not been previously reported.

Myogenic tumors in children and adolescents

Neoplasms of striated and smooth muscle in children are a diverse group of neoplasms that have some unique aspects in contrast to these tumors in adults. Rhabdomyosarcoma is the most common soft tissue sarcoma of infancy and childhood and is relatively common in adolescents. In contrast, smooth muscle tumors are relatively rare, and the various types of rhabdomyoma and smooth and skeletal muscle hamartomas are very uncommon. In recent years, the understanding of the pathologic and genetic aspects of rhabdomyosarcoma has been enhanced by adjunct techniques, such as immunohistochemistry and cytogenetic or molecular genetic analysis. The current classification of rhabdomyosarcoma emphasizes the histologic-prognostic correlations. This article reviews the clinicopathologic features of striated and smooth muscle tumors with an emphasis on the unique aspects of these neoplasms in children and adolescents and the differential diagnosis.

p16ink4a Expression in Benign and Malignant Melanocytic Conjunctival Lesions

Acquired conjunctival melanocytic lesions include nevi, primary acquired melanoses (PAMs), and melanomas. Conjunctival melanoma is a malignant melanocytic neoplasm with a high metastasis and mortality rate. Usually, the diagnosis can be achieved only with routine microscopic analysis, but in some cases, the samples are small or have artifacts. In these cases, complementary studies will be helpful, but currently, there are no well-understood or studied complementary methods. Objective. To analyze the immunohistochemical expression of p16 in conjunctival melanocytic lesions and to assess its potential for differentiating between benign and malignant melanocytic lesions. Methods. Immunohistochemical study against p16ink4a (p16) was performed on paraffin-embedded sections on 45 melanocytic lesions (9 melanomas, 19 nevi, and 2 PAMs with atypia and 15 without atypia). Expression was scored according to the German immunoreactive score (IRS). Results. Expression of p16 IRS differed between nevi, PAMs, and melanomas. The mean IRS for melanomas was 3.3 ± 1.8 and was lower than those for nevi (7.63 ± 3.24; P < .05), PAM with atypia (12 ± 0; P < .05), and PAM without atypia (11 ± 1.69; P < .05). Lesions with infiltration depths lower than 2 mm showed higher levels of p16. There were no differences between favorable and unfavorable locations. Conclusion. p16 Expression in conjunctival melanocytic lesions showed an expression similar to that in skin and seems to be a good marker to differentiate nevi and PAMs from melanomas. However, additional studies of larger series and follow-up are needed to confirm these findings.

A retrospective analysis of the clinicopathologic characteristics of uterine cellular leiomyomas in China

OBJECTIVE

To investigate the clinicopathologic features of uterine cellular leiomyomas (CLs) by comparing them with those of uterine leiomyosarcomas (LMSs).

METHODS

A case-control study comparing 78 cases of CL with 10 cases of LMS was conducted. The patients' records were reviewed to abstract information on tumors features and treatment, immunohistochemical findings, and disease prognosis.

RESULTS

The mean age at diagnosis was 45.3 ± 8.41 years in the CL group. The main clinical CL manifestations were menstrual abnormalities (56.4%), abdominal pain or distension (14.1%), and pelvic pressure (8.9%). Abdominal pain or distension was significantly more common in the LMS than in the CL group (P<0.05). Generally, CL tumors were smaller in diameter than LMS tumors (P<0.05). Moreover, lower levels of Ki-67 and PCNA expression were measured in CL than in LMS tumors (P<0.05). There were no cases of malignant transformation or metastasis in 41 patients with CL who adhered to long-tern follow-up.

CONCLUSION

No symptoms were found to be specifically associated with CL, and management of CL does not need to differ from that of ordinary leiomyoma. In contrast to malignant disease, CL has a favorable long-term prognosis. However, given its "borderline" pathologic nature, patients with CL require clinical surveillance.

Use of myocardin in the classification of mesenchymal tumors of the uterus

It can sometimes be difficult to distinguish between the 2 main types of uterine mesenchymal neoplasms; uterine smooth muscle tumors (SMTs) and endometrial stromal sarcomas (ESSs), particularly when the ESSs show smooth muscle differentiation or the SMTs are highly cellular. The aim of this study was to investigate myocardin expression in normal uterus myometrium, in SMTs, and in ESSs and to determine whether myocardin can be used as a useful diagnostic tool in the classification of problematic uterine mesenchymal tumors. Immunohistochemical staining was performed in each group. Besides myocardin, all cases were also stained for other smooth muscle markers (h-caldesmon, desmin, smooth muscle actin) and for CD10. All tested markers were analyzed in 21 conventional leiomyomas (LMs), 21 highly cellular leiomyomas (HCLs), 12 leiomyosarcomas (LMSs), 3 endometrial stromal nodules (ESNs), 11 ESSs, and 15 normal uterus myometrium. Myocardin was expressed in all normal uterine myometrium and in SMTs (even in the regions with epithelioid features) moderately or strongly, at least topically, whereas in endometrium, in ESNs and in ESSs, except in the regions of smooth muscle differentiation, it was negative. All ESNs, 11 of 11 ESSs and 14 of 15 endometrium were negative for h-caldesmon, but all SMTs and normal uterine myometrium were positive for h-caldesmon except for 2 LMSs, 2 HCLs, and for the regions with epithelioid features in 2 LMs. Desmin was stained in all normal uterine myometrium and in SMTs (except those of the regions with epithelioid features), but it was negative in 1 HCL and 1 LMS. One of 3 ESNs and 2 of 11 ESSs were expressed in desmin. Smooth muscle actin was negative in all ESNs, 2 LMSs, and 2 HCLs, and positive in all myometriums, LMs (except for the regions with epithelioid features), 1 ESSs, and 1 proliferative phase endometrium. Eight of 11 ESSs and all ESNs were positive for CD10, as was 1 HCL, and 2 LMSs. All uterine myometrium, 3 ESSs, and 3 endometriums were negative for CD10. Our study indicates that the myocardin is expressed in normal and neoplastic uterine smooth muscle cells sensitively and that the evaluation of myocardin expression is useful in distinguishing SMTs from ESSs.

Endometrial stromal sarcomas: a review of potential prognostic factors

Endometrial stromal tumors are uncommon mesenchymal tumors of the uterus. The classification of these tumors has evolved and the most current World Health Organization classification (2003) divides these neoplasms into: endometrial stromal nodule, low-grade endometrial stromal sarcoma, and undifferentiated endometrial sarcoma. The salient clinicopathologic features of these tumors are described, and a comprehensive review of literature pertaining to potential prognostic factors in endometrial stromal sarcomas is provided. Clinical factors, including age, race, parity and menopausal status, and pathologic factors, including tumor size, tumor stage, nuclear atypia, mitotic activity, tumor necrosis, lymphovascular space invasion, DNA ploidy and proliferative activity, and expression of hormone receptors, have been explored with varying outcomes. Surgicopathologic stage seems to be the most important prognostic factor in low-grade endometrial stromal sarcomas. The impact of other prognostic factors on survival is unclear or controversial, especially in patients with stage I tumors.

Smooth Muscle Tumors of the Female Genital Tract

Smooth muscle tumors are the most common among mesenchymal tumors in the female genital tract. The vast majority of these neoplasms are clinically benign and easy to diagnose. In contrast, leiomyosarcomas are highly aggressive tumors that may pose considerable diagnostic problems when they display unusual (myxoid or epithelioid) morphology, ambiguous histologic features for malignancy, or an unusual anatomic distribution. Diagnostic criteria for these problematic tumors vary depending on the site and type of histologic differentiation, and are based on a combination of 3 major criteria: (1) moderate to severe cytologic atypia; (2) increased mitotic index; and (3) tumor cell necrosis. Certain benign smooth muscle proliferations may show worrisome histologic features or unusual growth patterns, causing concern for leiomyosarcoma. Furthermore, other tumors, including perivascular epithelioid tumors, may mimic leiomyosarcoma. Careful attention to the clinical and anatomic setting, cytologic and architectural features, and immunohistochemical characteristics are helpful in distinguishing these entities. This article discusses conventional smooth muscle tumors as well as unusual subtypes, with emphasis on the diagnostic criteria and problems in differential diagnosis that arise at each site within the female genital tract.

Immunohistochemical Markers of Value in the Diagnosis of Mesenchymal Lesions of the Female Genital Tract

Pure mesenchymal tumors may occur anywhere in the female genital tract, but they are most common in the uterine corpus, leiomyoma being by far the most prevalent. These tumors, and other uncommon mesenchymal lesions within the uterine corpus and elsewhere in the female genital tract, may result in several diagnostic problems. Morphology remains paramount and, in most cases, an unequivocal diagnosis can be made based on examination of the hematoxylin and eosin stained sections, combined with an appreciation of the clinical and gross pathologic features. In difficult cases, immunohistochemistry can significantly contribute to the final diagnosis. In this article, the immunohistochemistry of neoplastic and nonneoplastic mesenchymal lesions of the female genital tract is discussed site by site, concentrating on markers that are of value in diagnosis and in differential diagnosis. The immunophenotype of mixed epithelial and mesenchymal neoplasms and pure epithelial neoplasms with a component of spindle cells is discussed, where appropriate, because these can enter into the differential diagnosis of a pure mesenchymal lesion.

Low-Grade Endometrial Stromal Sarcoma and Undifferentiated Endometrial Sarcoma: A Comparative Analysis Emphasizing the Importance of Distinguishing Between These Two Groups

Endometrial stromal sarcomas (ESSs) are rare tumors whose classification is still controversial. In this study, the authors studied 19 patients diagnosed with ESS at the Hospital S João, Porto, Portugal; reviewed their files and material; and performed immunohistochemical study for CD10, desmin, and smooth muscle actin markers, aiming to compare low-grade endometrial stromal sarcomas (LG-ESSs) and undifferentiated endometrial sarcomas (UESs) using the World Health Organization (WHO) classification. Twelve cases (63%) were classified as LG-ESS and 7 (37%) as UES. The median age at diagnosis was 49 years, and women with LG-ESS tended to be younger than those with UES. Most cases (7/11) had a previous echographic diagnosis of leiomyoma. A biopsy or curettage was performed in 6 cases, providing a definitive diagnosis of malignancy in 4. Frozen section was performed in 4 patients. The majority (63%) of patients were FIGO stage I. Twelve (63%) cases showed diffuse or focal expression of CD10. Desmin and smooth muscle actin expression was focal in 4 (21%) tumors. Patients with LG-ESS had a significant better overall survival than those with UES ( P = .026). Mitotic count had no prognostic significance. Our data emphasize the clinical importance of the WHO classification in ESS. It is of utmost importance to establish a proper classification to increase the consistency of data that may be useful for improving clinical and therapeutic management of patients with ESS.

Calretinin: diagnostic utility in the female genital tract

The utility of calretinin was first described in the diagnosis of mesothelioma. In the female genital tract, calretinin was initially reported in Wolffian remnants and related lesions and later used in the diagnosis of sex cord stromal tumors of the ovary, endometrial stromal tumors with sex cord-like differentiation, and uterine tumors resembling sex cord tumors of the ovary. This review discusses calretinin expression in normal tissues of the female genital tract and highlights its potential utility in the diagnosis of these subsets of neoplasms with emphasis to tumors that may constitute a problem in their differential diagnosis. In particular, the limited utility of calretinin in the diagnosis of sex cord stromal tumors of the ovary, in the differential diagnosis between mesothelioma and serous tumors involving the ovary and/or peritoneum, and in the differential diagnosis between Wolffian lesions and endometrial carcinoma are addressed.

Overexpression of progesterone receptor B increases sensitivity of human colon muscle cells to progesterone

Colon muscle strips and cells from female patients with slow-transit constipation (STC) exhibit impaired motility, signal transduction abnormalities characterized by downregulation of Gq/11 and upregulation of Gs proteins, decreased cyclooxygenase (COX)-1 and thromboxane (Tx)B2 levels, increased COX-2 and PGE2 levels, and overexpression of progesterone receptors (PGR). Progesterone (P4) treatment of normal cells reproduced these motility and signal transduction abnormalities. The purpose of the study was to examine whether overexpression of PGR-B reproduces these abnormalities by rendering the cells more sensitive to physiological concentrations of P4. Cultured human colon muscle was transfected with a plasmid DNA expressing PGR-B. The mRNAs of PGR, COX-1, COX-2, and Gq/11 were determined by quantitative real-time PCR. Their protein expression was determined by Western blot, and prostaglandins were measured by radioimmunoassay. Cultured muscle cells maintained their phenotypic features determined with myosin light chain (MLC) and h-caldesmon antibodies. Control and transfected muscle cells responded to 10(-6) M P4. In contrast, muscle cells transfected with PGR-B responded to lower P4 concentration (10(-7) M). This P4 concentration reduced MLC phosphorylation induced by CCK-8 (10(-8) M), downregulated Gq/11, and decreased COX-1 and TxB2 levels. It upregulated Gs proteins. It also increased COX-2 and PGE2 levels. We conclude that overexpression of PGR-B renders the cells more sensitive to physiological concentrations of P4. These results are consistent with the hypothesis that overexpression of PGR-B contributes to the motility and signal transduction abnormalities observed in female patients with STC and normal serum levels of P4.

Mullerian adenosarcomas: an immunophenotypic analysis of 35 cases

Mullerian adenosarcomas (MAs) are rare mixed mesenchymal and epithelial neoplasms that occur most commonly in the uterus. Although the epithelial component is typically benign, the mesenchymal component of most adenosarcomas morphologically resembles that observed in endometrial stromal tumors and is responsible for their clinical behavior. Thus, the differential diagnosis usually includes not only low-grade endometrial stromal tumors, but also adenofibroma, carcinosarcoma, and embryonal rhabdomyosarcoma especially in small samples. The objective of this study was to ascertain the immunophenotypic profile of the epithelial and mesenchymal components of MAs and delineate possible differences between conventional mesenchymal areas and areas of sarcomatous overgrowth. Representative sections from 35 MAs, 28 of them without sarcomatous overgrowth (MA-NSO) and 7 with sarcomatous overgrowth (MA-SO), were included in the study. Thirty tumors arose in the uterus, 4 were pelvic, and 1 originated in the colon. Adequate blocks were selected and immunostained for estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), CD10, WT1, smooth muscle actin, desmin, AE1/3 cytokeratin, CD34, calretinin, inhibin, c-kit, and Ki-67. The mesenchymal component expressed ER in 21/27 MA-NSOs but in only 1/7 MA-SOs (65% overall). PR was expressed in 21/26 MA-NSOs and 4/7 MA-SOs (76% overall), whereas AR was positive in 10/27 MA-NSOs and 5/7 MA-SOs (35% overall). CD10 was expressed in 23/28 MA-NSOs but in only 2/7 MA-SOs (71% overall), and WT1 positivity was seen in 22/27 MA-NSOs and 6/7 MA-SOs (79% overall). Sixty-seven percent of MAs expressed smooth muscle actin, 32% desmin, including both examples of MA-SOs with rhabdomyoblastic differentiation, and 25% expressed AE1/3 cytokeratin. CD34 expression was found in 35% of the tumors, but it was almost always patchy in distribution and weak in intensity, as was calretinin expression, seen only in 12% of the cases. Expression of c-kit and inhibin in greater than 5% of the tumor cells was not encountered. The median and mean Ki-67 labeling indices were 10% and 12%, respectively (range, <5% to 40%). The median and mean Ki-67 indices were both 5% in MA-NSOs compared with 30% and 28%, respectively, in MA-SOs. The epithelial compartment demonstrated expression for ER (24/32), PR (23/31), and AE1/3 cytokeratin (33/33); rare cases expressed CD10 (4 cases) and AR (1 case). In summary, the immunophenotype of most MAs resembled that of endometrial stromal tumors (positive for ER, PR, WT1, and CD10, with variable expression of muscle markers, AR and cytokeratin). The proliferative rate in the stromal component was strongly related to the presence of sarcomatous overgrowth. ER, PR, and CD10 expression was lost in MA-SOs relative to conventional low-grade stromal areas of mullerian/mesodermal adenosarcomas, reflecting the "dedifferentiation" of this component.

Pathology of uterine malignancies

This overview covers epithelial, stromal and mesenchymal malignancies of the body of the uterus, excluding the cervix. The distinction of type I and type II endometrial adenocarcinoma with the morphological variants of this tumour is discussed and some molecular aspects are explored. The concept of carcinosarcoma representing a metaplastic adenocarcinoma of the endometrium that behaves more like a carcinoma than a sarcoma is explained. Some types of mixed epithelial and stromal neoplasm are described and contrasted with carcinosarcoma. The concept of stromal sarcoma and high-grade uterine sarcoma is described and an outline of malignant smooth muscle tumours of the uterus includes a description of smooth muscle tumours of uncertain malignant potential and worrying benign smooth muscle lesions.

Application of immunohistochemistry to gynecologic pathology

CONTEXT

A large variety of tumors and lesions arise in the female genital tract. Although the majority of these can be correctly recognized on routine hematoxylin-eosin-stained slides, occasional cases present a diagnostic challenge. Immunohistochemical stains are extremely useful in resolving many of these problematic cases. As the knowledge in this area is constantly expanding, it is useful to have this updated information in a review form for easy access.

OBJECTIVE

To present our current knowledge of immunohistochemistry of the lesions of the female genital tract in a readily accessible form.

DATA SOURCES

The review is based on previously published articles on this topic.

CONCLUSIONS

Immunohistochemical stains help in reaching a conclusive diagnosis in a variety of problematic lesions seen in gynecologic pathology. As in any other system, immunohistochemical findings need to be interpreted in light of the clinical history and morphologic findings.

h-Caldesmon, Calretinin, Estrogen Receptor, and Ber-EP4: A Useful Combination of Immunohistochemical Markers for Differentiating Epithelioid Peritoneal Mesothelioma From Serous Papillary Carcinoma of the Ovary

Distinguishing between epithelioid peritoneal mesothelioma and papillary serous carcinomas involving the peritoneum may be very difficult, owing to overlapping morphologic features. Immunohistochemistry may facilitate establishing a correct diagnosis, but, as no single antibody has demonstrated absolute sensitivity and specificity for either mesothelioma or serous carcinoma, the differential diagnosis is based mainly on the combined use of several markers. The purpose of this study was to ascertain the sensitivity and specificity of a series of mesothelial markers [including more recently investigated antigens such as h-caldesmon (h-CD) and D2-40] and, using receiver operating characteristic curve analysis, to identify a selected appropriate panel of antibodies for differentiating between epithelioid peritoneal mesothelioma and serous papillary carcinoma of the ovary. Fifteen cases of epithelioid peritoneal mesothelioma and 40 cases of papillary serous carcinoma of the ovary (25 primary and 15 metastatic to the peritoneum) were immunostained for h-CD, D2-40, calretinin, cytokeratin 5/6, thrombomodulin, estrogen and progesterone receptors (ER and PR), Ber-EP4, B72.3, CA19-9, and CD15. h-CD and calretinin showed the highest sensitivity (100%), followed by D2-40 (93.3%) and cytokeratin 5/6 (93.3%); thrombomodulin had the lowest sensitivity (60%). h-CD and thrombomodulin had the best specificity (95%) for mesothelioma, followed by calretinin (87.5%), D2-40 (80%), and cytokeratin 5/6 (72.5%). Among carcinoma markers, ER and Ber-EP4 demonstrated the highest sensitivity (95%) followed by B72.3 (72.5%), PR (65%), CA19.9 (60%), and CD15 (45%). The specificity of the nonmesothelial markers was 100%, except for Ber-EP4 (93.3%). The relationship between the values of sensitivity and specificity of each marker using receiver operating characteristic analysis permitted the identification of h-CD, calretinin, ER, and Ber-EP4 as the markers with the best performance in differentiating epithelioid peritoneal mesothelioma from serous papillary carcinoma of the ovary.

High Frequency of JAZF1-JJAZ1 Gene Fusion in Endometrial Stromal Tumors With Smooth Muscle Differentiation by Interphase FISH Detection

The most common cytogenetic alteration observed in low-grade endometrial stromal tumors (EST) is the t(7;17)(p15;q21) translocation, resulting in the fusion of the JAZF1 and JJAZ1 genes. By reverse-transcription polymerase chain reaction, the translocation has been detected overall in one-third of ESTs, but only rarely in its variants. The purpose of this study was to develop a fluorescence in situ hybridization assay for detection of this translocation using archival paraffin-embedded samples of ESTs with smooth muscle differentiation and to assess the nature of the smooth muscle component of these tumors. Representative paraffin blocks of 9 endometrial stromal nodules and 1 low-grade endometrial stromal sarcoma were collected for the study. In 1 case, the block selected also contained areas of sex cordlike differentiation. A fluorescence in situ hybridization probe set was designed to detect the t(7;17)(p15;q12) on tissue sections. Six out of 10 collected ESTs were assessable. Fusion signals were detected in 3 out of 6 cases (50%) in both the conventional endometrial stromal and the smooth muscle components of the tumors. The tumor sample with sex cordlike differentiation harbored the fusion signal in all the 3 components. Our results support the contention that the endometrial stromal and smooth muscle components of these tumors have the same origin, either from a common precursor cell with pluripotential differentiation or from endometrial stromal cells that have undergone smooth muscle metaplasia. Our results indicate that the detection of this chromosomal abnormality can be used to diagnose ESTs with smooth muscle differentiation when the smooth muscle component is predominant.

Endometrial stromal tumours of the uterus: a practical approach using conventional morphology and ancillary techniques

Endometrial stromal tumours (ESTs) are diagnosed in most instances by light microscopy. Often, the greatest challenge is to distinguish between the different subtypes of these tumours. Furthermore, a handful of new or relatively new entities have been described in the literature, which may cause problems in the differential diagnosis; highly cellular leiomyoma is the most common. In addition, new antibodies have been developed to help in the distinction of ESTs from their mimics, as there are prognostic and therapeutic implications. A practical approach is provided for the diagnosis of ESTs on the basis of systematic assessment of histological and immunohistochemical parameters, and recent developments related to these tumours are highlighted.