Epithelioid sarcoma. An immunohistochemical study

Expression patterns for Bcl-2, EMA, β-catenin, E-cadherin, PAX8, and MIB1 in thymomas

The expression of immunohistochemical markers has been extensively investigated in thymomas to assist in the differential diagnosis. We have studied six select markers to determine their utility in the evaluation of these tumors. A series of 126 thymomas including 33 type A, 27 type AB, 20 type B1, 22 type B2, and 24 type B3, were examined utilizing a tissue microarray (TMA) technique with antibodies to e-cadherin, β-catenin, PAX8, bcl-2, EMA, and MIB-1. Keratin AE1/AE3 and p63 were used for quality control. A significant finding was strong and consistent positivity for bcl-2 in type A (90%) and type AB (88.8%) thymoma, while 100% of B1, B2, and B3 were negative. The distribution of e-cadherin and β-catenin was not useful for differential diagnosis. E-cadherin and β-catenin were expressed in a high proportion of all the tumors (92-100%), except for B2 thymoma which showed only 45% expression. A significant increase in the expression of the MIB-1 proliferation marker (mean: 12.8% nuclear positivity) was also observed in B3 thymoma compared with the other histologic types. Statistical significance was confirmed using Kruskal's non-parameterized test for distribution. EMA was generally negative except for spindle cells in the fibrous septa in types A and AB thymoma. PAX8 showed less consistent nuclear staining than p63 and was only widely expressed in 55.7% of cases. Bcl-2 may serve as a useful marker to separate spindle cell thymomas (Type A and AB) from the other types, and the MIB1 proliferation index may be of use to differentiate type B2 from type B3 thymoma.

Histone deacetylase inhibitor panobinostat induces antitumor activity in epithelioid sarcoma and rhabdoid tumor by growth factor receptor modulation

Background

Epithelioid sarcomas and rhabdoid tumors are rare, aggressive malignancies with poor prognosis. Both are characterized by INI1 alterations and deregulation of growth factor receptors albeit their interaction has not been elucidated.

Methods

In this study, we investigated the activity of a panel of epigenetic modulators and receptor tyrosine kinase inhibitors in vitro on respective cell lines as well as on primary patient-derived epithelioid sarcoma cells, and in vivo on xenografted mice. Focusing on histone deacetylase (HDAC) inhibitors, we studied the mechanism of action of this class of agents, its effect on growth factor receptor regulation, and changes in epithelial-to-mesenchymal transition by using cell- and RT-qPCR-based assays.

Results

Pan-HDAC inhibitor panobinostat exhibited potent anti-proliferative activity at low nanomolar concentrations in A204 rhabdoid tumor, and VAESBJ/GRU1 epithelioid sarcoma cell lines, strongly induced apoptosis, and resulted in significant tumor growth inhibition in VAESBJ xenografts. It differentially regulated EGFR, FGFR1 and FGFR2, leading to downregulation of EGFR in epithelioid sarcoma and to mesenchymal-to-epithelial transition whereas in rhabdoid tumor cells, EGFR was strongly upregulated and reinforced the mesenchymal phenotype. All three cell lines were rendered more susceptible towards combination with EGFF inhibitor erlotinib, further enhancing apoptosis.

Conclusions

HDAC inhibitors exhibit significant anticancer activity due to their multifaceted actions on cytotoxicity, differentiation and drug sensitization. Our data suggest that the tailored, tissue-specific combination of HDAC inhibitors with therapeutics which target cellular salvage mechanisms might increase their therapeutic relevance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08579-w.

Epithelioid Sarcoma-From Genetics to Clinical Practice

Epithelioid sarcoma is a mesenchymal soft tissue sarcoma often arising in the extremities, usually in young adults with a pick of incidence at 35 years of age. Epithelioid sarcoma (ES) is characterized by the loss of SMARCB1/INI1 (integrase interactor 1) or other proteins of the SWI/SNF complex. Two distinct types, proximal and distal, with varying biology and treatment outcomes, are distinguished. ES is known for aggressive behavior, including a high recurrence rate and regional lymph node metastases. An optimal long-term management strategy is still to be defined. The best treatment of localized ES is wide surgical resection. Neo-adjuvant or adjuvant radiotherapy may be recommended, as it reduces the local recurrence rate. Sentinel lymph node biopsy should be considered in ES patients. Patients with metastatic ES have a poor prognosis with an expected median overall survival of about a year. Doxorubicin-based regimens are recommended for advanced ES. Tazemetostat, an EZH2 methyltransferase, has shown promising results in ES patients. Novel therapies, including immunotherapy, are still needed.

Epithelioid sarcoma of the orbit

Epithelioid sarcoma is an aggressive and rare malignancy first recognized by Enzinger in 1970. It is known most commonly to affect the distal upper extremities in young adults. The classical "distal" form has a male predominance and can also involve other less frequent sites including lower extremities, proximal upper extremities, and the trunk. The "proximal" variant of this tumor is deep seated, tends to occur in older patients and predominantly develops in the pelvis, perineum, and genital tract. In the orbit, only a single report of two cases, which had a typical histopathologic appearance, has been previously published. We present the third case of orbital primary epithelioid sarcoma.

Epithelioid sarcoma and unclassified sarcoma with epithelioid features: clinicopathological variables, molecular markers, and a new experimental model

BACKGROUND

Epithelioid sarcoma (ES) and unclassified sarcoma with epithelioid features (USEF) are clinically and therapeutically unresolved. We compared ES and USEF patients' clinical behavior, treatment, outcome, and molecular marker expression. Furthermore, preclinical ES study models were developed to enable comprehensive benchside investigations.

PATIENTS AND METHODS

A database of ES and USEF patients (n = 116) treated since 1992 was created. A clinically annotated ES-USEF tissue microarray (TMA) was assayed for tumor-related markers. Newly established human and commercially available ES cell lines were characterized and tested in vivo.

RESULTS

ES and USEF patients presenting with localized disease exhibited 22% and 25% local recurrence rates, 35% and 19% nodal metastasis rates, and 41% and 53% distant metastasis rates (median follow-up, 54 months and 39 months, respectively). The 5- and 10-year disease-specific survival rates were 88% and 43% and 52% and 42% (ES and USEF, respectively). TMA immunohistochemistry identified integrase interactor (INI)-1 loss, cancer antigen 125, and p53 nuclear expression as significantly more common in ES than USEF cases. Both cell lines preserved ES morphological and biochemical characteristics in vitro and in vivo; loss of INI-1 was shown to occur in both lines.

CONCLUSIONS

Enhanced knowledge of ES and USEF clinical behavior, marker expression, and molecular determinants, extended via experimental models, will hopefully accelerate development of urgently needed effective targeted therapies for ES and USEF.

Undifferentiated tumor: true identity by immunohistochemistry

CONTEXT

"Undifferentiated tumor" refers to a heterogeneous group of neoplasms with little or no evidence of differentiation on routine light microscopic morphology.

OBJECTIVE

To identify the true identity of undifferentiated tumors by immunohistochemical analysis.

DATA SOURCES

Review of the pertinent literature and the authors' experience.

CONCLUSIONS

For treatment and prognostic evaluation, it is crucial to delineate whether an undifferentiated neoplasm is epithelial, mesenchymal, melanocytic, or hematopoietic in nature. Application of a screening panel to demonstrate the expression of markers of major lineages is fundamental for determination of the broad category of neoplasia. Because poorly differentiated carcinomas and in particular sarcomatoid carcinomas are known to be heterogeneous in their antigen expression, several epithelial markers in combination may be required to establish the carcinomatous nature of tumor. A diagnostic misinterpretation as a consequence of occasional aberrant or unexpected antigen expression is best avoided by using a broad panel that includes both antibodies that are anticipated to be positive and those that are expected to be negative. In this treatise, the immunohistochemical dissection of undifferentiated tumors on the basis of their morphologic features is outlined, supplemented with algorithmic immunohistochemical analysis for each morphologic category of small round cell tumors, carcinomatous tumors, sarcomatous (or sarcoma-like) tumors, and tumors with histologically overlapping features, including hematolymphoid malignancies, melanoma, and sarcomas with epithelioid appearance. The utility of several organ- or tissue-specific markers in the context of undifferentiated tumors is reviewed.

Epithelioid sarcoma of Enzinger

Epithelioid sarcoma was named in 1970 in a classic paper by Enzinger, who expanded the observations in a larger series in 1985. He defined a sarcoma with a peak incidence in young adult males and a predilection for extremities, involving subcutis or deeper tissue and extending along tendon sheaths or aponeuroses. The tumor forms nodules with central necrosis surrounded by bland polygonal cells with eosinophilic cytoplasm and peripheral spindling. Fibromalike, angiomatoid, and proximal aggressive variants (with larger cells, prominent nuceloi, and rhabdoid change) have since been described. Epithelioid sarcomas regularly express vimentin, cytokeratins, and epithelial membrane antigen, and about half are positive for CD34, but a wide range of other antigens can be expressed. S100 protein, desmin, and FLI-1 are usually negative. The ultrastructure displays epithelial and mesenchymal features including myofibroblastic differentiation. There are no specific genetic findings but several cases display chromosomal abnormalities in the 22q region. The tumor has no normal cellular counterpart and differs from both synovial sarcoma and carcinoma. There is a wide differential diagnosis from numerous benign and malignant conditions, including granuloma annulare, melanoma, and epithelioid vascular neoplasms. Epithelioid sarcoma has a high recurrence rate, which can be reduced by adequate surgery, and up to 40% metastasize, to regional lymph nodes, to lung, and other locations including scalp. Adverse prognostic factors include large size, male sex, older age, necrosis, vascular invasion, rhabdoid cytomorphology, and inadequate excision. Thirty-six years after Enzinger's original account, epithelioid sarcoma remains a clinically and pathologically distinct, indolent but aggressive sarcoma of indeterminate lineage.

SMARCB1/INI1Tumor Suppressor Gene Is Frequently Inactivated in Epithelioid Sarcomas

Epithelioid sarcoma is a rare soft tissue neoplasm of uncertain lineage that usually arises in the distal extremities of adults, presents a high rate of recurrences and metastases and frequently poses diagnostic dilemmas. The recently reported large-cell "proximal-type" variant is characterized by increased aggressiveness, deep location, preferential occurrence in proximal/axial regions of older patients, and rhabdoid features. Previous cytogenetic studies indicated that the most frequent alterations associated with this tumor entity affect chromosome 22. In this study, combined spectral karyotyping, fluorescence in situ hybridization, and array-based comparative genomic hybridization analyses of two proximal-type cases harboring a rearrangement involving 10q26 and 22q11 revealed that the 22q11 breakpoints were located in a 150-kb region containing the SMARCB1/INI1 gene, and that homozygous deletion of the gene was present in the tumor tissue. The SMARCB1/INI1 gene encodes for an invariant subunit of SWI/SNF chromatin remodeling complex and has been previously reported to act as a tumor suppressor gene frequently inactivated in infantile malignant rhabdoid tumors. We analyzed SMARCB1/INI1 gene status in nine additional epithelioid sarcoma cases (four proximal types and five conventional types) and altogether we identified deletions of SMARCB1/INI1 gene in 5 of 11 cases, all proximal types. We confirmed and further extended the number of cases with SMARCB1/INI1 inactivation to 6 of 11 cases, by real-time quantitative PCR analysis of mRNA expression and by SMARCB1/INI1 immunohistochemistry. Overall, these results point to SMARCB1/INI1 gene involvement in the genesis and/or progression of epithelioid sarcomas. Analysis of larger series of epithelioid sarcomas will be necessary to highlight putative clinically relevant features related to SMARCB1/INI1 inactivation.

Molecular cytogenetic characterization of proximal-type epithelioid sarcoma

Proximal-type epithelioid sarcoma is a recently described soft-tissue tumor that is distinguished from conventional-type epithelioid sarcoma by a far more aggressive clinical course, frequent location in the proximal anatomic regions, and variable rhabdoid morphology. Because of their rarity and peculiar morphology, proximal-type epithelioid sarcomas frequently pose serious diagnostic dilemmas, being easily misdiagnosed as a variety of other malignant neoplasms. To date, the information available on the genetic alterations associated with this tumor entity has been confined to single conventional cytogenetic reports. In this article, we present the results of a conventional and molecular cytogenetic analysis of six proximal-type epithelioid sarcomas. Spectral karyotyping analysis of these cases deciphered the characteristics of several marker chromosomes and complex translocations, leading to the recognition of recurrent rearrangements. The most frequently involved chromosome arm was 22q, and the identification of two cases with a similar translocation, t(10;22), suggests a role for one or more genes on chromosome 22 in the pathogenesis of this tumor and provides an opportunity for finely mapping the translocation-associated breakpoints. Chromosome arm 8q gain was also a frequent event and correlated with gain of MYC gene copy number, as demonstrated by fluorescence in situ hybridization. A review of both cases reported in the literature and those presented in this study reinforced the involvement of chromosomes 8 and 22 and also indicated frequent rearrangements of chromosomes 7, 14, 18, and 20.

Cytological features of epithelioid mesenchymal neoplasms: A study of 21 cases

Epithelioid mesenchymal neoplasms (EMNs) are rare tumors that share cytological, histological, and immunohistochemical features with epithelial tumors. It is important to distinguish EMNs from epithelial tumors in cytology specimens due to their different clinical management and prognosis. The cytomorphological features of histologically confirmed EMN were reviewed. Twenty-one cytological specimens of EMN were evaluated and characterized by polygonal cells with moderate to abundant dense cytoplasm, prominent nucleoli, and pleomorphism. Additional findings included the presence of a distinct population of spindle cells, hemosiderin-containing cells, multinucleated cells, and granuloma-like structures in selected cases. Cytokeratin immunoreactivity was seen in two cases and was negative in one case. This study shows that the cytological features of EMNs and epithelial tumors overlap; nonetheless, some features are more helpful in suggesting EMN. A panel of immunocytochemical studies must include specific mesenchymal markers to avoid a misdiagnosis of carcinoma in cases of cytokeratin-positive EMN.

Proximal-type epithelioid sarcoma: case report and result of comparative genomic hybridization

BACKGROUND

Epithelioid sarcoma is a rare mesenchymal neoplasm. Recently, a more aggressive, so-called "proximal type" epithelioid sarcoma has been described.

CLINICAL CASE

A 40-year-old-woman presented with 5 x 4 cm, erythematous, indurated, non-movable, painful mass on the pubic area. Histopathology demonstrated diffuse tumor-cell infiltration into the subcutaneous and fascia, which was consisted of prominent epithelioid cells and scattered rhabdoid cells. A multinodular growth pattern or granulomatous appearance with central necrosis was not observed. The tumor cells showed positive reactions for vimentin, cytokeratin (AE1/AE3), and CD34. Despite the surgery, left inguinal mass with lymphadenopathy occurred one month later. We also carried out comparative genomic hybridization (CGH) with tumor cells. CGH revealed chromosomal gain of 5q32-qter, 12q24-qter, and 22q.

CONCLUSION

We report a case of proximal-type of epithelioid sarcoma, which showed the chromosomal gains of 5q32-qter, 12q24-qter, and 22q by CGH.

Epithelioid sarcoma: new insights based on an extended immunohistochemical analysis

CONTEXT

Epithelioid sarcoma has a distinctive epithelioid phenotype and characteristically exhibits immunohistochemical reactivity for epithelial markers (keratins and epithelial membrane antigen) and mesenchymal markers (most notably vimentin and CD34). Antibodies to certain keratin subunits and other novel antigens now available to surgical pathologists have not been tested on a large number of cases.

OBJECTIVE

To assist in the differential diagnosis of epithelioid sarcoma and to help elucidate its histogenesis through an expanded immunohistochemical profile.

DESIGN

Immunohistochemical testing with diverse antibodies was performed on 95 archived epithelioid sarcomas including 73 classic and 22 histologically variant subtypes retrieved from the files of the Armed Forces Institute of Pathology.

RESULTS

Immunohistochemical reactivity (number positive/number of cases tested [percent positive], frequency of staining) included keratin 14 (31/64 [48%], variable), gamma-catenin (35/74 [47%], variable), keratin 5/6 (10/33 [30%], focal), calretinin (8/40 [20%], focal), keratin 20 (11/71 [15%], focal), p63 (3/20 [15%], focal), whereas 9 invasive cutaneous squamous cell carcinomas showed strong p63 positivity, epithelial-specific antigen (10/74 [14%], variable), CD117/Kit (5/37 [14%], focal), keratin 15 (3/23 [13%], rare cell), mesothelin (2/64 [3%], rare cell), and CD10 (1/41 [2%], rare cell). No reactivity was observed for keratins 2, 5, and 10.

CONCLUSIONS

Diagnostically, p63 and keratin 5/6 distinguish cutaneous squamous cell carcinoma (positive) from epithelioid sarcoma (usually negative). No single immunomarker was able to distinguish the main 4 histologic subtypes of epithelioid sarcoma, indicating that they are all histogenetically related lesions. The limited expression of specific keratin subtypes used in our study supports the notion that epithelioid sarcoma is a mesenchymal neoplasm capable of partial epithelial transformation.

CD31 staining in epithelioid sarcoma

We report an unusual case of epithelioid sarcoma. The tumour occurred in the finger of a 27-year-old female. The clinical history, histology and the electron microscopy of the lesion were typical for epithelioid sarcoma. However, immunohistochemical analysis showed strong membranous CD31 staining, a finding hitherto not described. All other robust vascular markers, including factor-VIII-related antigen (FVIIIrag) were negative. The findings were compared with the available literature data, leading us to conclude that there is insufficient evidence for endothelial derivation of epithelioid sarcoma, but in the differential diagnosis with vascular tumours CD31 may stain and to rule out angiosarcoma FVIIIrag is a useful antibody.

Cytokeratin 7 and 20 expression in epithelioid sarcoma

BACKGROUND

Epithelioid sarcoma (ES) is a rare malignant soft tissue tumor of uncertain histogenesis that arises predominantly in the extremities of young adults. Immunohistochemically, the neoplastic cells are typically positive for vimentin, low molecular weight cytokeratin (CAM5.2) and epithelial membrane antigen (EMA).

METHOD

We examined eight cases of ES from seven different patients. All cases were studied with immunohistochemistry for EMA, CAM5.2 (keratin 8 and 18), 34BE12 (keratins 1, 5, 10 and 14/15), cytokeratins 7 and 20 (CK7, CK20), and CD34.

RESULTS

The average patient age was 53 (range 43-76) and the male:female ratio was 5:2. The location was the upper extremity in five tumors, the lower extremity, the perineum, and the paraspinal soft tissue in one tumor each. All cases contained predominantly epithelioid cells, but spindle cells were also present in three cases. All cases contained areas of geographic necrosis. CAM5.2 was strongly positive in seven tumors and focally positive in one (8/8). EMA was diffusely positive in two cases and focally positive in five cases (7/8). CD34 was diffusely positive in 3/8 cases. 34BE12 was diffusely positive in one case and focally positive in two others (3/8). CK7 was diffusely positive in one case and focally positive in another (2/8). CK20 was negative in all cases (0/8). All cases tested were positive for vimentin (6/6), 2 cases were focally positive for HHF35 (2/5), and all cases tested were negative for S-100 protein (0/7).

CONCLUSIONS

In addition to the known immunoreactivity for CAM5.2 and EMA, there is positivity for CK7 and 34BE12 in a small proportion of cases. None of the cases expressed CK20. This immunophenotypic profile suggests that ES is more similar to carcinoma and synovial sarcoma than to other soft tissue tumors, and may be of diagnostic utility.

Keratin expression in human tissues and neoplasms

Keratin expression in human tissues and neoplasms Keratin filaments constitute type I and type II intermediate filaments (IFs), with at least 20 subtypes named keratin 1-20. Since certain keratin subtypes are only expressed in some normal human tissues but not others, and vice versa, various tissues have been subclassified according to the pattern of keratin staining. Simple epithelia generally express the simple epithelial keratins 7, 18, 19, and 20, while complex epithelia express complex epithelial keratins 5/6, 10, 14, and 15. When an epithelium undergoes malignant transformation, its keratin profile usually remains constant. The constitution and expression patterns of keratin filaments in human epithelial neoplasms are complex and often distinctive. In this article, we first briefly review the molecular and cell biology of keratin filaments. We then focus on the expression patterns of keratin filaments in various human neoplasms.

Primary epithelioid sarcoma of the dura: case report

OBJECTIVE AND IMPORTANCE

Epithelioid sarcomas are rare mesenchymal neoplasms that occur most often in the extremities of young adults. Despite isolated reports of epithelioid sarcomas arising in the head and neck region, these lesions have not been described previously, to our knowledge, in the central nervous system.

CLINICAL PRESENTATION

We present the case of an 18-year-old woman with a unique dural sarcoma that arose in the right frontotemporal region. As visualized on magnetic resonance imaging studies, the 4.5-cm tumor focally traversed the cranium to penetrate the galea, the temporal muscle, and subcutaneous tissue. No brain invasion was noted.

INTERVENTION

Despite gross total removal and postoperative radiotherapy (59 Gy), a large recurrence was noted 5 months after surgery. Histologically, the partly necrotic tumor consisted of epithelioid and spindle cells showing widespread vimentin and variable cytokeratin as well as epithelial membrane antigen immunoreactivity. Ultrastructurally, the cohesive cells featured various organelles, intermediate filaments, junctions, and filopodia-containing intercellular spaces.

CONCLUSION

With the inclusion of epithelioid sarcoma, the spectrum of central nervous system sarcomas continues to expand.

Spindle cell variant of epithelioid sarcoma: an easily misdiagnosed tumour

Epithelioid sarcoma is a histologically distinct soft tissue sarcoma of high grade malignancy. We report a case of epithelioid sarcoma in a young man who presented with multiple nodules over the left forearm, with bony invasion and pulmonary metastases. The histological features of the dermal tumour were those of a malignant spindle cell tumour with positive cytokeratin and vimentin staining and differed from the classical epithelioid sarcoma in its absence of typical necrobiotic nodular epithelioid pattern. It was the clinical presentation and the histology of the subcutaneous nodules that led to the final diagnosis of epithelioid sarcoma. This case illustrates a predominance of spindle cell pattern in the dermal tumour of epithelioid sarcoma, which has previously been reported as fibroma-like variant of epithelioid sarcoma.

DNA copy number changes in epithelioid sarcoma and its variants: a comparative genomic hybridization study

Epithelioid sarcoma is a distinctive, rare soft tissue sarcoma that typically involves the distal extremities in young adults, and shows epithelioid morphology and immunohistochemical markers of epithelial differentiation. The genetic background of epithelioid sarcoma is poorly understood, and knowledge of it could give insights into the pathogenesis of this tumor and its possible relationship with other malignant tumors. In this study, we analyzed DNA copy number changes in 30 epithelioid sarcomas by comparative genomic hybridization. DNA was extracted from microdissected samples of formaldehyde-fixed and paraffin-embedded tumors with a minimum of 60% of tumor cells in each sample. Sixteen tumors (53%) showed DNA copy number changes at one to six different genomic sites. The majority of the changes were gains, seen in 14 tumors, whereas 10 tumors showed losses. The most common recurrent gains were at 11q13 (five cases), 1q21-q23 (four cases), 6p21.3 (three cases), and 9q31-qter (three cases). High-level amplifications were detected once in 6p21.3-p21.1 and once in 9q32-qter. Recurrent losses were seen at 9pter-p23 (three cases), 13q22-q32 (three cases), 1p13-p22 (two cases), 3p12-p14 (two cases), 4q13-q33 (two cases), 9p21 (two cases), and 13q32-qter (two cases). The most common recurrent gain at 11q13 was seen in both classic cases and angiomatoid and rhabdoid variants supporting the relationship of these variants with the classic epithelioid sarcoma. Expression of cyclin D1 gene, located in 11q13, was immunohistochemically detected in nine of 15 cases including three of five cases with gain of 11q13, suggesting its involvement in epithelioid sarcoma. The observed comparative genomic hybridization changes give targets for future genetic studies on epithelioid sarcoma.

Epithelioid sarcoma: an immunohistochemical analysis of 112 classical and variant cases and a discussion of the differential diagnosis

Epithelioid sarcoma (ES) is a distinctive soft tissue neoplasm with a predilection for the distal extremities of young adults. This tumor typically contains nodular aggregates of epithelioid and spindle cells with zonal necrosis. The neoplastic cells are generally reported to coexpress keratin and vimentin and are often stated to be positive for CD34. However, there is no large series with extensive immunohistochemical data, there are few data with regard to expression of different keratin subtypes, and there are no large series discussing the epithelioid sarcoma subtypes. In the current study, we immunohistochemically evaluated 88 typical and 24 variant (8 angiomatoid, 9 large cell/rhabdoid, and 7 "fibroma-like") ESs. Nearly all ESs with typical histology (94%) were positive for keratin 8 (K8), whereas 72% were positive for K19, 48% for intermediate- and high-molecular-weight keratins (34betaEH12), and 22% for K7; reactivity with the latter two antibodies was usually seen in only a minority of tumor cells. Vimentin reactivity was present in all cases, EMA in 96% of cases and muscle-specific actin and CD34 were noted in 41% and 52% of the cases, respectively. A few ESs (7%) showed focal cytoplasmic CD31 reactivity, but none exhibited a distinctive membrane staining pattern, and examples tested for FVIIIRAg were negative. The angiomatoid, fibroma-like, and large cell-rhabdoid ES variants had immunohistochemical profiles similar to the classic cases, supporting a common pathogenesis. Although not consistently expressed in ES, the presence of CD34 is helpful in distinguishing this entity from primary and metastatic carcinomas and other sarcomas such as malignant rhabdoid tumor.

Epithelioid sarcoma of the penis. Clinicopathologic study of a tumor with myogenic features and review of the literature concerning this unusual location

Soft tissue tumors of the penis are uncommon. We report here the clinicopathologic features of a penile epithelioid sarcoma (ES), review the literature concerning this unusual location and focalize our attention on its differentiation. The 34-year-old patient was admitted for abrupt urinary retention due to the growth of a firm and painful plaque on the left side of the shaft, three years previously clinically diagnosed as Peyronie's disease. Magnetic nuclear resonance revealed an infiltrating lesion of both corpora cavernosa. Histology of bioptic fragments showed a nodular malignant spindle and epithelioid cell tumor with focal necrosis and relatively high mitotic rate. Based on the immunohistochemical data (cytokeratin+, vimentin+, EMA+, CD34+, and S100-), the diagnosis of ES was strongly considered. Penectomy was undertaken and the diagnosis confirmed by both light and ultrastructural microscopy. The 22 month follow-up was free of recurrences and metastases. Although not dissimilar from the 10 previously described ES of the penis in terms of natural history and histology, the tumor reported here showed myogenic features as revealed by both immunohistochemistry (immunoreactivity for muscle specific actin) and ultrastructure (intercellular junctions, discontinuous basal lamina, pinocytotic vesicles and thin filaments with intercalated dense bodies). Although previously observed in ES of other sites, this feature has never been established in ES of the penis.

Epithelioid sarcoma: presence of vascular-endothelial cadherin and lack of epithelial cadherin

AIMS

To evaluate the pattern of cadherin expression in epithelioid sarcoma.

METHODS AND RESULTS

Seven epithelioid sarcomas were immunostained by a polyclonal antibody that detects all cadherin subtypes and by monoclonal antibodies that detect epithelial cadherin (E-cadherin) and vascular-endothelial cadherin (VE cadherin). In addition, the tumours were immunostained for a variety of epithelial (cytokeratin, EMA, AUA1) and endothelial (Factor VIII-related antigen, CD34, CD31) markers. Tumours cells of all seven epithelioid sarcomas expressed cadherins. Surprisingly, E-cadherin was not detected in any of the sarcomas. VE-cadherin was detected in five of seven cases. All seven tumours expressed cytokeratins and EMA but none expressed AUA1. CD34 was detected in six of seven cases and CD31 was detected in a single case. No case expressed Factor VIII-related antigen.

CONCLUSIONS

Most epithelioid sarcomas strongly express cadherins, a feature which may contribute to their epithelioid appearance. The absence of detectable E-cadherin suggests that epithelial differentiation in these tumours is, at most, incomplete. The expression of VE-cadherin by the majority of cases, in the absence of E-cadherin, is consistent with an element of mesenchymal differentiation, possibly endothelial or perineurial. The additional presence of other markers such as CD34 and CD31 in some cases favours endothelial differentiation.

Allelic loss on chromosome 22q in epithelioid sarcomas

Epithelioid sarcomas are soft tissue tumors with an indolent, but potentially aggressive, clinical behavior. Distinction from other benign and malignant entities may be a diagnostic dilemma. In this study, we evaluate the presence of loss of heterozygosity (LOH) of chromosome 22q in tumor DNA from 13 epithelioid sarcomas, four epithelioid angiosarcomas, and two epithelioid hemangioendotheliomas, and investigate its possible role in diagnosis. LOH was detected in 6 of 10 (60%) of the informative epithelioid sarcomas. No allele loss was detected in the informative vascular tumors, three angiosarcomas, and two hemangioendotheliomas. Chromosome 22q carries the locus of a tumor suppressor gene, the neurofibromatosis 2 (NF2) gene, which has been shown to be lost or mutated in some NF2-related tumors, sporadic meningiomas, and vestibular schwannomas, as well as a few other tumors. Our data suggest that a region of chromosome 22q may be the locus of a tumor suppressor gene involved in the tumorigenesis of these neoplasms. Genetic alterations of yet-unknown tumor suppressor genes in this region, or even the NF2 tumor suppressor gene, may play a role in epithelioid sarcomas tumorigenesis. The fact that LOH was only detected in epithelioid sarcomas and not in the vascular tumors studied suggests a possible role for this marker in diagnosis.

Epithelioid sarcoma of the tongue

A case of epithelioid sarcoma in the tongue is reported. The patient, a 35 year old woman, presented with a non-ulcerated painful lesion of the tongue. Microscopically, the tumour was characterised by multiple coalescent nodules with central geographic necrosis infiltrating the lingual muscle. The tumour cells were epithelioid with abundant eosinophilic cytoplasm and atypical nuclei. Immunohistochemically, the tumour cells stained for vimentin, keratin, and epithelial membrane antigen. These morphological and immunohistochemical appearances led to the diagnosis of epithelioid sarcoma of the tongue. Seven years later, the patient died with metastatic dissemination to the scalp, lungs, and brain. No case of epithelioid sarcoma arising in the tongue has been described previously.

Epithelioid Sarcoma Presenting as a Benign Foot Ulcer

Background:

Epithelioid sarcomas are rare mesenchymal tumours that infrequently present to dermatologists. The often banal spindle and polygonal cell histology can mimic granulomas.

Objective:

Our aim is to raise the clinician's awareness of a potentially devastating malignancy that can remain unsuspected.

Method:

We present a case of an epithelioid sarcoma that was misdiagnosed as a benign foot ulcer and treated as such for nearly half a year. An uncertain histology further delayed definitive treatment. At the time of surgery, the tumour had infiltrated deeply.

Conclusion:

The often nondescript clinical and histologic nature of epithelioid sarcomas demands a high level of vigilance on the part of the clinician.

"Proximal-type" epithelioid sarcoma, a distinctive aggressive neoplasm showing rhabdoid features. Clinicopathologic, immunohistochemical, and ultrastructural study of a series

Eighteen examples of an unusual malignant soft-tissue neoplasm, the morphology of which ranged from that of "atypical" epithelioid sarcoma to that of a rhabdoid tumor or undifferentiated carcinoma (with transitional forms) are described. Patients included 11 males and seven females; their median age was 35.5 years with most patients aged 20 to 40 years. Development of a mass was the main presenting symptom. Six tumors developed in the pelvis and perineal region, four in the pubic region and vulva, three in the buttocks, one in the deep soft tissues of the left hip, one on the penis, one in left forearm, one in left axilla, and one on the occiput. Tumor size ranged from 1 to 20 cm (median, 4 cm). On microscopic examination, the tumor cells invaded the subcutaneous or deep soft tissues, had prominent epithelioid or rhabdoid features, had marked cytologic atypia, and grew in a multinodular pattern in half of the cases. Areas of necrosis were often seen. A granuloma-like pattern reminiscent of that observed in classic epithelioid sarcoma was observed in only two cases. Immunohistochemically, positivity for cytokeratin, epithelial membrane antigen, and vimentin was seen in all but one of the cases. Of 16 cases, 10 and eight tumors reacted with desmin and CD34, respectively; five of 15 reacted at least focally with smooth-muscle actin, whereas three of 13 and one of 10 reacted for HMB-45 and carcinoembryonic antigen, respectively. S-100 protein and CD31 yielded negative results. Seven tumors were investigated at the ultrastructural level, four of which showed prominent intracytoplasmic intermediate filament aggregates, often accumulating into paranuclear whorls, which is in keeping with the rhabdoid phenotype. Five tumors showed features of epithelial differentiation (i.e., tonofilament-like structures or desmosomes or both), whereas one tumor displayed features of myofibroblastic differentiation. Differential diagnoses include mainly conventional epithelioid sarcoma, extrarenal malignant rhabdoid tumor, epithelioid malignant peripheral nerve sheath tumor, melanoma, rhabdomyosarcoma, and undifferentiated carcinoma. Follow-up information on 14 patients (range, 4 months to 8 years; median, 19 months) revealed local recurrence in one case and metastatic dissemination in six patients, leading to death in five. In our opinion, the above-described neoplasms represent a usually "proximal-type" of epithelioid sarcoma. In contrast to the conventional, "distal-type" epithelioid sarcoma, the proximal variant is characterized by a predominantly large-cell, epithelioid cytomorphology, marked cytologic atypia, frequent occurrence of rhabdoid features, and lack of a granuloma-like pattern in most cases. It appears to be somewhat more aggressive (or at least metastasizes earlier) than usual epithelioid sarcoma.

Mitotic granuloma annulare: a clinicopathologic study of 20 cases

The finding of mitotic figures in granuloma annulare (GA) has not been emphasized in the literature. We describe 20 cases of a cellular, mitotically active variant of GA; we defined this group as cases having > or = 1 mitosis per 10 hpf. Clinically, the lesions could not be distinguished from typical, localized GA: there were 9 males and 11 females with a mean patient age of 49 +/- 15 years (mean +/- SD), compared to 45 +/- 20 years in a randomly selected control group of 60 patients with GA, and no unusual sites of predilection were noted. Histologically, a classic, palisading granuloma pattern predominated (18/20 cases). Lesions were located in the mid-dermis and tended to be more cellular than typical GA. The histiocytes comprising the lesion often had enlarged nuclei and prominent nucleoli. The number of mitoses per 10 hpf was 3.0 +/- 1.5 (range 1.0-7.2), control group 0.3 +/- 0.5; occasional atypical mitotic figures were observed. The proliferative nature of these lesions was confirmed using MIB-1 staining; the percentage of MIB-1 positive cells ranged from 5%-29% (mean 15 +/- 6%). Mitotic GA must be distinguished histologically from neoplastic processes, in particular epithelioid sarcoma. We conclude that histiocytes in clinically typical GA can exhibit an increased mitotic rate. Recognition of this variant is important in order to avoid overdiagnosis of a malignant condition.

Epithelioid sarcoma with an 18q aberration

Epithelioid sarcoma is a peculiar soft-tissue neoplasm of uncertain origin, which is characterized by an epithelioid morphology of tumor cells coexpressing epithelial (keratin) and nonepithelial (vimentin) antigens. We herein report a new cytogenetic abnormality with der(22)t(18;22)(q11;p11.2) in a case of epithelioid sarcoma that occurred in the elbow of a 75-year-old man. Histologically, the tumor demonstrated a multinodular proliferation of epithelioid cells, with positive immunostaining for keratin, epithelial membrane antigen (EMA), and vimentin. Cultured tumor cells obtained from fresh surgical materials were frozen in plastic ampules and stocked in a liquid nitrogen freezer. Six years after surgery, the cells were recovered from the freezer and utilized for both morphologic and cytogenetic analyses. These cultured cells both before and after the freezing exhibited essentially the same epithelioid morphology and immunophenotypes as those of the original tumor. A chromosome analysis, together with fluorescence in situ hybridization (FISH), demonstrated a 61-67 modal population, and a characteristic clonal abnormality with der(22)t(18;22)(q11;p11.2). Other clonal abnormalities included numerical (-3, -4, +7, -13, -14, -16, -18, +20, -22) and structural (8p+, 9p+, 12p+, i(21q)) aberrations. Some variant clones also demonstrated i(18q). Since the breakpoint at 18q11 is similar to that reported in synovial sarcoma, this finding may support the presence of a histogenetic relationship between epithelioid sarcoma and synovial sarcoma. Our study thus indicates that the storage of frozen cells is useful for both morphologic and cytogenetic analyses of soft tissue tumors.

Keratin immunoreactivity in melanoma of soft parts (clear cell sarcoma)

Seven of 24 soft tissue melanomas were shown to express keratins using antibodies CAM 5.2, LP34 and MNF116. No clinical or histological differences were seen in these seven cases when compared with the 17 keratin negative cases.

Epithelioid sarcoma of the orbit

BACKGROUND

Epithelioid sarcoma is a rare and aggressive malignancy commonly occurring in the tendon sheaths of the distal extremities of young adults. This article presents the clinical and pathologic details of two patients with epithelioid sarcoma in the orbit, the first to be reported as occurring in this location.

METHODS

The clinical history, results of physical and radiologic examination, surgical procedures, pathologic specimens, and clinical course of each patient were reviewed and recorded.

RESULTS

Biopsies were performed of the masses that were found in the superotemporal orbit of both patients. Results of pathologic examination in each patient caused considerable difficulty, and the correct diagnosis was reached only after extensive consultation. The first patient underwent wide soft tissue and bone exenteration and is alive without recurrence at 3 years. The second patient had multiple recurrences and died of recurrent and metastatic disease at 29 months.

CONCLUSIONS

Epithelioid sarcoma must be added to the differential diagnosis of orbital sarcomas. The histology is nodular with a pseudogranulomatous appearance. Based on our limited experience, epithelioid sarcoma of the orbit may have a course similar to that which occurs elsewhere in the body, requiring aggressive surgical treatment at the outset.

Epithelioid sarcoma in childhood: An immunohistochemical, electron microscopic, and clinicopathologic study of 11 cases under 15 years of age and review of the literature

Epithelioid sarcoma in a rare tumor and most of the cases occur in young adults. It is rare in childhood. We have been able to obtain data and histologic material for 11 patients with this disease. The primary sites were head and neck in three patients, inguinal region in one, and extremities in seven. The age range of the patients was 12 weeks to 13 years. There was a preponderance of males over females with a ratio of 1.75. The tumors presented with a typical nodular necrotizing pattern. In three cases giant osteoclast-like cells were present. The immunohistochemistry and electron microscopy showed features consistent with previous observations on epithelioid sarcomas. In one case islands of small dark cells noted on light microscopy were surrounded by basal lamina on electron microscopy. The cells inside the nests were undifferentiated. Six tumors studied by flow cytometry were in DNA diploid range. On follow-up, five children are alive and well 2 to 7 years after treatment. Three children died of tumor progression with metastases to lymph nodes and lungs. One child had been diagnosed only recently, and in one the disease has run a protractive course with multiple recurrences. The behavior of these epithelioid sarcomas in children is similar to that seen in adults, the prognosis being dependent on radical tumor surgery preventing recurrent disease. Long-term follow-up is necessary because the tumor may recur many years after the primary tumor was removed.

Epithelioid monophasic synovial sarcoma

A 47-year-old man presented with a soft tissue mass of the distal right thigh near the knee. The tumor was highly vascular with epithelioid tumor cells growing in a peritheliomatous pattern, suggesting a soft tissue glomus tumor. Yet many tumor cells contained hemosiderin pigment and formed papillary structures suggestive of pigmented villonodular synovitis. Tumor cells were cytologically bland, and there was minimal mitotic activity. The tumor cells were strongly immunoreactive for cytokeratin, however, and contained true desmosomes, gland lumina, microvilli, tonofilaments, and well-developed basal lamina. These findings plus the absence perinuclear aggregates of intermediate filaments rule out malignant rhabdoid tumor and epithelioid sarcoma. Also, magnetic resonance imaging revealed no other lesions to suggest metastatic carcinoma. Thus this tumor appears to be a predominantly epithelioid form of monophasic synovial sarcoma. Recognition of this variant of synovial sarcoma is important for prognostication and therapeutic decision making because some studies indicate that this variant of synovial sarcoma follows a relatively benign clinical course.

DNA flow cytometry of epithelioid sarcoma

DNA ploidy of paraffin-embedded tissue from 11 patients with epithelioid sarcoma and 20 control specimens (granuloma annulare and sarcoid) was studied. DNA aneuploidy was found in 64% of the epithelioid sarcomas and in none of the control samples. Aneuploidy did not correlate with necrosis, vascular invasion, or mitotic rate. There was also no association of aneuploidy with adverse outcome.

Keratin and carcinoembryonic antigen (CEA) in human melanoma cells

Human melanomas are known to contain vimentin intermediate filaments but there has been some dispute about their expression of cytokeratins. The cytoplasm of human M21 melanoma cells maintained in culture reacted with a rabbit anti-keratin antibody and two monoclonal anti-keratin antibodies AE1 and AE2. Cells derived directly from subcutaneous xenografts of M21 melanoma in nude mice, however, failed to express cytokeratins. The presence of keratin filaments in cultured M21 cells was confirmed by electronmicroscopic and immuno-electronmicroscopic examinations of cell extracts. Polyacrylamide gel electrophoresis (PAGE), revealed 46 KD keratin proteins in cultured M21 cells. Small amounts of these low molecular weight keratins were detected by PAGE in M21 melanoma xenografts even though immunofluorescence and immunoperoxidase assays failed to demonstrate keratin at the light microscopic level. Immunofluorescence revealed keratin and carcinoembryonic antigen (hitherto undetected in human melanomas) first on the 9th day of culture of xenograft-derived M21 cells. The appearance of keratin and CEA in M21 melanoma cells in vitro was not affected by inhibition of cellular proliferation or as a result of exposure to methotrexate or adriamycin. However, adriamycin altered the cytoplasmic distribution of keratin.

Epithelioid sarcoma: an electron-microscopic, immunohistochemical and DNA flow cytometric analysis

Eight epithelioid sarcomas (ES) were studied by electron microscopy, immunohistochemistry, and DNA flow cytometry. Ultrastructurally, the tumour cells showed desmosome-like intercellular junctions and numerous microvilli, in addition to whorled arrangements of intermediate filaments. Tumour cells were positive for epithelial membrane antigen, cytokeratin, and vimentin, and negative for carcinoembryonic antigen and desmin. All seven cases examined by flow cytometry showed diploid or hyperploid (near diploid) DNA content. This seems to correspond to the relatively long clinical course and low-grade malignant nature of ES. Although the histogenesis of ES is still uncertain, the results of this study suggest that it is a tumour of primitive mesenchymal cells with the capacity to show epithelial differentiation.

Epithelioid sarcoma in a dog

A tumour in an 11-year-old male crossbred Fox Terrier, showing the clinical and pathological features of epithelioid sarcoma in man is reported. Clinical aspects, location, peculiar pattern of spread and evolution, together with histopathological and immunohistological findings of this rare tumour simulating a granuloma are described. Controversial histogenesis is discussed.

Epithelioid sarcoma: clinical and histologic characteristics

Epithelioid sarcoma is a slow-growing sarcoma that typically occurs on an upper extremity of young men. It commonly arises as a deep soft tissue, subcutaneous, or as a dermal, woody, hard nodule.

Rhabdoid tumors of soft tissues: a clinicopathologic study of 26 cases enrolled on the Intergroup Rhabdomyosarcoma Study

Twenty-six cases of malignant soft tissue tumors with features similar to renal rhabdoid tumors were identified among approximately 3,000 childhood sarcomas entered on Intergroup Rhabdomyosarcoma Studies I-III. The tumors consisted of polygonal cells with vesicular nuclei and prominent nucleoli and cytoplasmic intermediate filament inclusions as identified by electron microscopy and immunohistochemistry. The growth pattern was predominantly solid or solid-trabecular. Immunohistochemistry showed vimentin, wide spectrum keratin, and epithelial membrane antigen to be the most consistent antigenic phenotypes. Eleven patients were infants less than 1 year of age. The tumors affected predominantly soft tissues of proximal extremities, trunk, and retroperitoneum/pelvis/abdomen. Nineteen patients died within 1 to 82 months (median, 6 months) from the start of treatment. Five patients have survived the disease for 2 to 13 years. When compared with the survival analysis of 991 Intergroup Rhabdomyosarcoma Study II patients, it was obvious that this group of tumors fares very poorly (P less than .001). The tumor belongs to the group of soft tissue neoplasms showing mesenchymal and subtle epithelial differentiation, similar to epithelioid sarcoma. Because of its identifiable histology, site and age distribution, and poor outcome, it warrants a status as an independent entity.

Epithelioid sarcoma mimicking angiosarcoma: the value of immunohistochemistry in the differential diagnosis

Epithelioid sarcoma (ES) is a rare malignant tumour of young adults, usually presenting as a skin ulcer or subcutaneous nodule in the distal portion of the upper limb. Multiple recurrences and late metastases are typical, leading to fatality in a third to one-half of all cases. The slow evolution of the tumour is one reason for its delayed recognition. The other is its frequent histological misinterpretation, in particular, as a peculiar granulomatous reaction. In our case, the primary tumour presented a variant morphological pattern so closely mimicking a cavernous angiosarcoma as to mislead several reputable opinions. Later recurrences and metastases were typical of ES, while a focal angiomatoid pattern was maintained. The morphology and immunoreactivity to a wide spectrum of tumour markers is compared with that of six file cases of classical ES. Retrospectively, all neoplastic lesions in our patient were ES. In young adults, lesions of the upper extremity, even when angiomatoid or haemorrhagic, should raise a suspicion of ES. Once epithelioid sarcoma is suspected, the differential diagnosis can be elucidated on immunohistochemical grounds. Early diagnosis provides the best opportunity for radical surgery at a stage when the tumour has not spread locally or disseminated systemically.

The immunoperoxidase localization of tumour markers in ovarian cancer: the value of CEA, EMA, cytokeratin and DD9

Primary tumours from 40 patients with epithelial ovarian cancer, treated at St Thomas's Hospital over a 10-year period, were studied for the immunocytochemical expression of the following tumour markers in formalin-fixed paraffin embedded material: carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), cytokeratin (CAM 5.2), and DD9. An indirect immunoperoxidase staining technique was used. All of the tumours were positive for EMA and CAM 5.2, and 30% of them were positive for both CEA and DD9. The absence of CEA and DD9 may be of value in differentiating between metastatic abdominal adenocarcinomas of ovarian origin and those of gastrointestinal origin, but no indication of prognosis was obtained using these epithelial markers. The strong and widespread staining of all the tumours for EMA suggests that this may be a useful marker for detecting metastatic or recurrent disease by immunoscintigraphy.

Primary epithelioid sarcoma of the hard palate. A case report

A case of primary epithelioid sarcoma of the hard palate is described with no evidence of metastases. Review of the literature revealed no other reported cases of epithelioid sarcoma at this site. The patient, a 20-year-old male negro, returned with 2 local recurrences after initial excision but with no evidence of metastases. He remains well with no evidence of disease at present. This report records a unique primary site for this tumour, and illustrates the diagnostic difficulties, both clinical and histological, which this tumour may present.