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

Epithelioid sarcoma of the parotid gland of a child

Epithelioid sarcoma is a rare soft-tissue tumor that usually occurs in young adults, with a median age of 26 years. This malignancy has been divided into distal and proximal types. The latter is found in proximal body sites including the head and neck region. We present a rare case of parotid proximal-type epithelioid sarcoma in a 1-year-old male child; this is the 4th reported case in the literature and the youngest in a pediatric patient to date. The tumor showed prominent rhabdoid features by light microscopy. Immunohistochemical studies revealed positive staining to cytokeratin (AE1/AE3), epithelial membrane antigen, vimentin, and BAF47. Thus, while the tumor resembled a malignant rhabdoid tumor, the positive staining for BAF47 supported instead a diagnosis of epithelioid sarcoma, according to our current understanding of these 2 tumor types. Also, the clinical course was not the typical aggressive behavior of a rhabdoid tumor. The patient underwent radical parotidectomy without adjuvant therapy and remained disease-free at follow-up, 14 months after surgery.

Epithelioid sarcoma of the vulva in a 17-year-old pregnant woman

Epithelioid sarcoma of the vulva is an extremely rare neoplasm with aggressive behavior and poor outcome. Herein, we report a case of vulvar epithelioid sarcoma presenting in a 17-year-old very early in her pregnancy. The patient presented with an asymptomatic nodule of the right labia majora of 1-year duration. Computerized tomographic scans showed enlarged inguinal lymph nodes and numerous lung nodules. Positron emission tomography was performed and revealed no suspicious lesions for metastatic disease. The patient underwent local excision of her vulvar lesion. On the basis of morphology and extensive immunohistochemistry, the lesion was classified as epithelioid sarcoma. The patient was referred to radiation therapy and upon evaluation, she was found to be in her sixth week of gestation. The patient continued with her pregnancy and underwent a lymph node dissection, which was positive. We review the literature of only the well-documented cases extensively studied by immunohistochemical analysis. We summarize the clinical presentation, clinical impression, treatment modalities, and outcomes of these cases. On account of the rarity of this disease in the vulva, there is no clear consensus on treatment modalities, but it seems that early aggressive surgical resection is the treatment of choice, with the role of adjuvant therapy to be determined.

Epithelioid sarcoma of the neck: case report

Epithelioid sarcoma is an aggressive, malignant tumour of the soft tissue which tends to arise in proximity to large tendons and aponeuroses. We report the case of a patient presenting with an epithelioid sarcoma arising in the neck. A 56-year-old man was referred with a three-year history of a sensory disorder as well as a slowly growing mass in his right neck. The patient underwent resection of the tumour by means of a conservative neck dissection. The final diagnosis, based on the histological and immunohistochemical findings, was epithelioid sarcoma. Radiotherapy was performed after the operation. The post-operative course was uneventful, and there was no local recurrence or distant metastasis.

Epithelioid sarcoma

Epithelioid sarcomas are rare, mesenchymal tumors of unknown histogenesis and display multidirectional differentiation, which is predominantly epithelial. They have no normal cellular counterpart and differ from both synovial sarcoma and carcinoma. They account for less than 1% of all soft tissue sarcomas and are usually slow growing, with peak incidence in young adult men and occur predominantly in extremities. Histologically, they form nodules, with central necrosis surrounded by bland, polygonal cells with eosinophilic cytoplasm and peripheral spindling. They regularly express vimentin, cytokeratins, epithelial membrane antigen, and CD34, whereas staining is usually negative with S100, desmin, and FLI-1. Ultrastructurally, they display epithelial and mesenchymal features, including myofibroblastic differentiation. They manifest no specific cytogenetic findings, but several cases have displayed chromosomal abnormalities in 22q region. Clinically, they have a high recurrence rate, and up to 50% of epithelioid sarcomas metastasize. Proximal, fibroma-like, and angiomatoid variants have been described. The proximal variant (with larger cells, prominent nucleoli, and rhabdoid changes) is clinically more aggressive.

CD34-reactive tumors of the skin. An updated review of an ever-growing list of lesions

Over the past few years, a growing number of cutaneous tumors expressing CD34 is being reported. The list contains benign and malignant neoplasms as well as reactive and hamartomatous lesions of diverse lineages of differentiation, including fibroblastic, myofibroblastic, fibrohistiocytic, vascular, neural, adipocytic, smooth muscle, hematopoietic, melanocytic and epithelial. The more frequent diagnostic difficulties are found in spindle cell proliferations, mainly in those of the fibrocytic lineage. In part, this is because of the fact that in this area are, aside to well-defined entities, histologically and clinically diverse, recently reported cutaneous CD34-reactive lesions, whose definitions, limits and relationships are not completely established. The CD34 expression plays a key role in the differential diagnosis of some tumors, such as dermatofibrosarcoma protuberans, epithelioid sarcoma or pleomorphic hyalinizing angiectatic tumor of soft parts, with important therapeutic consequences. In others, as in desmoplastic trichilemmoma, it can help to resolve diagnostic problems in concrete cases. Finally, in many of the CD34-positive lesions, the diagnosis with the hematoxylin and eosin stain is straightforward. However, in all of them, the knowledge of the immunohistochemical profile contributes to our understanding of the cutaneous pathology.

Epithelioid sarcoma: a clinicopathologic and immunohistochemical analysis of 106 cases from the French sarcoma group

Epithelioid sarcoma (ES) is rare with a poor prognosis and for which a loss of INI1 expression has been recently reported. We report a study of 106 cases with clinical, histologic, and immunohistochemical data, including INI1 expression, and follow-up data. Of the 106 cases, 70 were the conventional subtype and 36 the large cell subtype. INI1 was negative in 86 cases (81.1%): 57 (81%) of 70 conventional and 29 (81%) of 36 large cell subtypes. Treatment modalities were available for 76 and follow-up for 80 patients. Of the 80 patients, 43 (54%) experienced metastasis and 25 (31%) died of the disease. Univariate analysis indicated that tumor size and mitotic index were significant for metastasis-free survival, whereas proximal location, tumor size, tumor multifocality, and mitotic index were significant for overall survival. Loss of expression of INI1 is frequent in the conventional and large cell subtypes of ES and can be used as a diagnostic marker, but it has no prognostic impact.

A case of epithelioid sarcoma arising in the vulva

Epithelioid sarcoma of vulva is extremely rare. Only 20 cases have been reported in the literature so far. Early diagnosis is difficult because of its benign appearance as a painless subcutaneous nodule. Therefore treatment can be delayed, although epithelioid sarcoma requires prompt surgery. We report a case of epithelioid sarcoma that occurred in the left vulva with a brief review of literature.

Myxoid Epithelioid Sarcoma: Clinicopathologic Analysis of 2 Cases

In the nearly 4 decades since its original delineation as a distinct clinicopathologic entity, several morphologic variations of epithelioid sarcoma have been described. Proximal, angiomatoid, and fibroma-like variants have been reported, as have cases displaying significant hyalinization, calcification, and/or ossification. Furthermore, it has long been recognized that epithelioid sarcoma may display focal myxoid change. Herein, the authors describe 2 examples of epithelioid sarcoma that displayed diffuse myxoid change. Both cases were otherwise typical, both morphologically and immunophenotypically, of epithelioid sarcoma. The tumors in both cases were localized, and the patients were treated with wide local excision followed by adjuvant radiotherapy. The patients are free of disease recurrence after 25 and 37 months of follow-up. Differential considerations that may arise because of the composite of morphologic and immunophenotypic findings noted in these cases are discussed, especially if encountered in a small biopsy. These cases further expand the morphologic spectrum of epithelioid sarcoma.

Magnetic resonance imaging findings of vulvar epithelioid sarcoma

We describe here a case of vulvar epithelioid sarcoma. Epithelioid sarcoma is a malignant appendicular skin tumor that is rarely of vulvar origin. Magnetic resonance imaging (MRI) revealed a solid mass with an ulcer-like lesion and multilobulated contour. To our knowledge, this is the first case of vulvar epithelioid sarcoma described in the MRI literature.

Renal medullary carcinoma: rhabdoid features and the absence of INI1 expression as markers of aggressive behavior

Renal medullary carcinoma is a rare, well-recognized highly aggressive tumor of varied histopathology, which occurs in young patients with sickle cell trait or disease. Rhabdoid elements, occasionally seen in high-grade renal tumors including renal medullary carcinoma, possibly represent a pathologic marker of aggressive behavior. INI1 (hSNF5/SMARCB1/BAF47) is a highly conserved factor in the ATP-dependent chromatin-modifying complex. Loss of this factor in mice results in aggressive rhabdoid tumors or lymphomas. In humans, the loss of INI1 expression has been reported in pediatric renal rhabdoid tumors, central nervous system atypical teratoid/rhabdoid tumors and epithelioid sarcomas, a possible primary soft tissue rhabdoid tumor. This study compares five renal medullary carcinomas with 10 high-grade renal cell carcinomas (five with rhabdoid features), two urothelial carcinomas and two pediatric renal rhabdoid tumors. All five renal medullary carcinomas, irrespective of histopathology, showed complete loss of INI1 expression similar to that seen in pediatric renal rhabdoid tumors. In contrast, all renal cell carcinomas or urothelial carcinomas, including those with histological rhabdoid features, expressed INI1. Clinically, all five of the patients with renal medullary carcinoma and the two patients with rhabdoid tumors presented with extra-renal metastases at the time of diagnosis. This study demonstrates that renal medullary carcinoma and renal rhabdoid tumor share a common molecular/genetic alteration, which is closely linked to their aggressive biological behavior. However, the absence of INI1 expression is not necessarily predictive of rhabdoid histopathology but remains associated with aggressive behavior in renal medullary carcinoma.

Epithelioid sarcoma: the University of Washington experience

BACKGROUND

Epithelioid sarcoma is a rare sarcoma with a high local recurrence rate that frequently metastasizes to lymph nodes. We reviewed our experience with adjuvant therapy in patients with this disease.

METHODS

Between 1990 and 2003, we treated 11 patients with epithelioid sarcoma. Patient, tumor, and treatment characteristics were analyzed, and effect of treatment on survival was evaluated by the Kaplan-Meier method.

RESULTS

Nine men and 2 women were treated. Tumors presented on the trunk, the upper extremities, and the lower extremities. Five patients developed nodal disease. All patients underwent surgery for the primary tumor, and 7 patients had nodal evaluation. Ten patients underwent adjuvant chemotherapy, and 9 underwent radiotherapy. Recurrence developed in 9 patients. Five-year disease-free and overall survival rates were 46% and 65%, respectively. Chemotherapy and radiation therapy did not impact disease-free survival.

CONCLUSIONS

Although surgery remains the primary treatment modality, multi-institutional trials are needed to develop more effective adjuvant therapy for patients with epithelioid sarcoma.

Myoepithelial carcinoma of soft tissue in children: an aggressive neoplasm analyzed in a series of 29 cases

Primary myoepithelial tumors of soft tissue are uncommon, and criteria for malignancy among these neoplasms have only recently been established. Of 51 myoepithelial carcinomas of soft tissue in the literature, 11 occurred in children, 7 of which were included in a previous series of myoepithelial tumors from our group. We have collected an additional 22 cases of myoepithelial carcinoma of soft tissue in the pediatric population, and we describe the detailed clinicopathologic features of all 29 cases herein. There were 15 girls and 14 boys; age at diagnosis ranged from newborn to 17 years (median, 9 y). Sites included extremities (14 cases), trunk (6 cases), viscera (5 cases: 3 mediastinal, 1 retroperitoneal, and 1 intracardiac), and head/neck (4 cases). Histologically, the tumors were heterogeneous, with epithelioid, clear, spindle and/or plasmacytoid cells forming nests, cords or solid sheets in a myxoid or hyalinized stroma. Epithelioid cells predominated in the majority of cases (27 of 29; 93%) and in 10 cases (34%), tumor cells focally had scant cytoplasm with round cell morphology. The mitotic rate ranged from <1 to 68 per 10 high power fields (median, 8), and tumor necrosis was present in 14 cases. At least 1 broad-spectrum cytokeratin was positive in all tumors [CAM5.2 in 17 of 18 (94%), AE1/AE3 in 15 of 20 (75%), and PAN-K in 14 of 21 (67%)], and EMA was positive in 19 of 29 cases (66%). Either S100 or GFAP was positive in all but 4 cases [S100 in 21 of 29 (72%) and GFAP in 15 of 28 (54%)]. Clinical follow-up in 23 cases revealed that 9 patients had local recurrences (53% of the 17 patients who underwent complete excision with negative margins); 12 (52%) developed metastases; and 10 (43%) have died of disease so far, at a median interval of 9 months after diagnosis. Despite the relative rarity of carcinomas in the pediatric population, myoepithelial carcinoma seems to be disproportionately common among children and often has an aggressive clinical course.

Human chorionic gonadotrophin producing epithelioid sarcoma metastatic to the placenta

Pregnancy complicated by sarcoma is a rare event, and metastasis to the placenta is exceptionally rare. Of reported malignancies involving the products of conception, only 8% are sarcomas. We report the first case of placental metastasis of an epithelioid sarcoma, an uncommon malignancy which most frequently affects young adults. In addition to the typical histological features and immunophenotypic profile expected of epithelioid sarcoma, this tumor also expressed human chorionic gonadotrophin (HCG). Although uncharacteristic, the production of HCG has been previously reported in other nontrophoblastic tumors. It may have contributed to the pathogenesis of the tumor metastatic to the placenta in this case.

Epithelioid sarcoma: prognostic factors and survival in a series of patients treated at a single institution

BACKGROUND

Epithelioid sarcoma (ES) is a rare subtype of soft-tissue sarcoma of unknown histogenesis. Typically, it occurs superficially as single/multiple nodules (nodular ES), or in deeper tissues as a mass. The correlation between initial presentation and clinical outcome was investigated.

METHODS

Fifty-four consecutive patients surgically treated at a single referral center were retrospectively reviewed. Thirty-six patients presented with a primary and 18 with a recurrent tumor. Potential prognostic clinicopathological variables, including macroscopic features at first presentation, were tested by univariable and multivariable analysis with respect to overall (OS), metastasis-free (MFS), and local recurrence-free survival (LRFS).

RESULTS

The 10-year OS was 61.8% for the whole series. Thirty patients relapsed; in detail, local and distant failure occurred in 14 (25.9%) and 24 (44.4%) patients, respectively. The lymph node involvement rate was 16/54 (29.6%). In both the whole series and the subset of patient with primary ES, single localized tumor correlated with increased OS at multivariable analysis; occurrence of nodal involvement during postoperative follow-up correlated to worse OS and MFS. Nodular ES was an independent predictor of worse LRFS. In univariable analysis, nodular ES was associated with smaller tumor size, distal limb locations, earlier classification of malignant tumor (TNM) stage, and higher amputation rate. A statistical difference in the pattern of failure between nodular and mass ES was found.

CONCLUSIONS

Primary tumor macroscopic features seem to correlate to different local aggressiveness and failure patterns. Better prognosis is associated with single localized disease stage and no occurrence of locoregional spread.

Immunohistochemistry of INI1 expression: a new tool for old challenges in CNS and soft tissue pathology

Immunohistochemical staining for INI1 (BAF47) expression has been recently described. Loss of expression of INI1 as detected by immunohistochemical staining correlates with deletion and mutations of the INI1 gene in patients with malignant rhabdoid tumors and central nervous system atypical teratoid/rhabdoid tumors and as such is a sensitive and specific marker for these tumors. Loss of INI1 expression may rarely be encountered in other tumor types. This article reviews the utility of immunohistochemical staining for INI1 expression.

Primary epithelioid sarcoma of the oesophagus

Epithelioid sarcoma is a rare soft tissue tumour presenting two main variants: the 'classical' distal type and the more recently described proximal type. The latter is distinguished from the former by occurrence in elderly patients, more axial and deep location, prominent atypical and pleomorphic appearance and eventually aggressive clinical behaviour with poor outcome. To date, only few perivisceral epithelioid sarcomas have been described, and they are mainly related to the colon and bladder in pelvic and perineal sites. We report a hitherto undescribed epithelioid sarcoma of the distal oesophagus and discuss the relevance of molecular cytogenetics.

Soft Tissue Tumors of the Hand. 2. Malignant

Soft tissue tumors of the hand arise from skin, subcutaneous tissue, tendons, nerve, and blood vessels. Many of these lesions occur on other parts of the body; however, the hand remains a unique site because these tumors have symptoms, appearances, treatments, and prognoses that may be quite different than when on other parts of the body. Their characteristics and the severity of symptoms vary markedly depending on the exact location, size, and type of tumor-and many of these tumors can have multiple forms of presentation. Two articles are intended to provide an overview of benign (previous article) and malignant tumors (this article) of the hand. The rarer and more deleterious tumors are discussed in detail while the common tumors and epidermal lesions with which practitioners are familiar are briefly overviewed. At the completion of these review articles, participants should be able to identify and diagnose various benign and malignant hand tumors as well as understand the accepted current treatment of these growths.

Proximal-type epithelioid sarcoma--a rare, aggressive subtype of epithelioid sarcoma presenting as a recurrent perineal mass in a middle-aged male

BACKGROUND

Epithelioid sarcoma (ES) is an uncommon soft tissue sarcoma. Lately, subtypes of ES, including proximal-type ES have been recognized, with relatively few reports on such cases.

CASE PRESENTATION

A 47-year-old male presented with a perineal soft tissue mass that was excised elsewhere and the biopsy was submitted for a review diagnosis. On histology, a multi nodular tumor was seen comprising sheets of oval to polygonal cells with moderate amount of cytoplasm. Interspersed were larger, rhabdoid cells with abundant eosinophilic cytoplasm and prominent nucleoli. Focal necrosis was noted. A wide panel of immunohistochemical (IHC) markers was performed to rule out a range of differential diagnoses, including a poorly differentiated carcinoma, a melanoma and a variety of sarcomas with epithelioid differentiation. On IHC, the tumor cells showed a polyphenotypic expression, including positivity for epithelial markers i.e cytokeratin (CK), CK7, EMA and mesenchymal markers like vimentin and CD 34. Desmin was focally positive. CK20, CEA, S-100, HMB-45, SMA, LCA and CD31 were negative. A diagnosis of a proximal-type ES was formed. Six moths later, despite adjuvant chemo and radiotherapy (CT and RT), the patient continued to have the lesion and was referred again. In addition to the earlier histological features, sections from the persistent tumor mass showed an increased number of larger cells along with multinucleated tumor giant cells.

CONCLUSION

The value of identifying this uncommon tumor from a list of differential diagnoses is in view of its aggressive behavior, as seen in our case. A wide excision with clear margins is imperative with options of post-operative CT/RT in individual cases during a close follow-up.

Renal cell carcinoma with rhabdoid features: an aggressive neoplasm with overexpression of p53

CONTEXT

Adult renal cell carcinoma (RCC) with rhabdoid features is a recently recognized morphologic variant of kidney carcinoma. To date, only very few studies have been published on this subject and p53 was not previously studied.

OBJECTIVE

To evaluate clinical attributes, morphology, and immunohistochemistry in RCC with rhabdoid component.

DESIGN

Reviewing a consecutive series of 310 RCCs, we identified 14 cases of RCC with rhabdoid features. All cases were reviewed and subjected to detailed clinical and pathologic studies with immunohistochemical evaluation of p53.

RESULTS

All tumors were clear RCCs with rhabdoid component representing from 5% to 50% of the tumor volume. Rhabdoid cells were large with a central eosinophilic intracytoplasmic inclusion and an eccentric atypical nucleus. Tumor necrosis was common (13/14) and sometimes extensive. Nine of 14 tumors were staged pT3, 4 of 14 were pT2, and only 1 tumor was pT1. On immunohistochemistry, rhabdoid cells were positive for vimentin (14/ 14), epithelial membrane antigen (11/14), and cytokeratin (9/14). Desmin and smooth muscle actin were always negative. p53 was positive in 10 of 14 tumors in the rhabdoid areas (5%-50% of tumor cells stained) but only in 5 of 14 cases in usual clear renal cell areas. In the follow-up, 10 of 14 patients developed metastases and 6 of 14 died of the disease. The median of survival was 8 months.

CONCLUSIONS

We showed that RCC with rhabdoid features is a very aggressive neoplasm with a poor prognosis. We observed an overexpression of p53 in the rhabdoid component that may be implicated in the tumor dedifferentiation.

Proximal-type epithelioid sarcoma of the perineum: Calling attention of urologists

A subcutaneous mass in the perineum of a middle-aged man was excised and pathologically diagnosed at first as 'undifferentiated carcinoma' of unknown origin, which recurred 2 years later without any metastasis. Further histological evaluation ultimately established a correct diagnosis of 'proximal-type epithelioid sarcoma', a variant of rare epithelioid sarcoma. This type of tumor may confuse pathologists because its histological characteristics resemble undifferentiated carcinoma or malignant rhabdoid tumor. Frequent immunoreactivity of CD34, in addition to expression of keratins, epithelial membrane antigen and vimentin, provides strong support for the diagnosis of this rare neoplasm. Urologists should be aware that this sarcoma commonly occurs in the genital regions.

[Soft tissue non lymphoid malignant round cell tumors in childhood and adolescence: morphological, immunophenotypic, and molecular features of diagnosis]

Soft tissue non lymphoid malignant round cell tumors observed in children and adolescents are rare and are very different from adult tumors. They are often undifferentiated and distinctive key morphologic features are often lacking, but, on the other hand, specific recurrent genetic alterations, mostly translocations, are distinctive. Immunohistochemical features are also important for the diagnosis, and there is sometimes a strong correlation between the presence or the absence of an immunoreactivity for a specific protein and the presence of a specific genetic alteration. Finally, careful morphologic histological examination and immunohistochemical features will lead to a diagnosis which will be often confirmed by cytogenetics (translocations) or molecular techniques (fusion transcripts, deletion, mutation).

Proximal-type epithelioid sarcoma with elevated serum CA 125: report of a case with CA 125 immunoreactivity

Proximal-type epithelioid sarcoma is a recently described rare soft tissue neoplasm. It is commonly found in the pelvic, perineal, and genital areas in middle-aged or older adults, as compared with the classic type of epithelioid sarcoma, which arises in the distal portion of the extremities in adolescents and young adults. Proximal-type epithelioid sarcoma has a more aggressive clinical behavior than the classic type of epithelioid sarcoma. Proximal-type epithelioid sarcoma is histologically characterized by a diffuse proliferation of epithelioid cells with prominent rhabdoid feature. Recently, a few cases have been reported of epithelioid sarcoma with elevated serum CA 125 level and CA 125 immunoreactivity in neoplastic cells. These cases raise the possibility that serum CA 125 and CA 125 immunoreactivity could be a useful tumor marker for diagnosing and monitoring epithelioid sarcoma. We describe a case of proximal-type epithelioid sarcoma with elevated serum CA 125 level (up to 3395 U/mL [reference range, <35 U/mL]) in a 12-year-old girl who presented with a huge pelvic mass measuring 12 cm in greatest dimension. The serum CA 125 level dropped to 452 U/mL after a debulking operation of the mass. Immunostaining for CA 125 demonstrated a positive immunoreactivity in the neoplastic cells. She received one cycle of chemotherapy and died of the disease 2 months after diagnosis. This case represented a rare example of proximal-type epithelioid sarcoma with elevated serum CA 125 and immunoreactivity for CA 125 in the tumor cells. Based on the previous reported cases and the current case, serum CA 125 as well as immunohistochemical stain for CA 125 may be a useful tumor marker of proximal-type epithelioid sarcoma.

Prognostic significance of dysadherin expression in epithelioid sarcoma and its diagnostic utility in distinguishing epithelioid sarcoma from malignant rhabdoid tumor

Dysadherin is a cancer-associated cell membrane glycoprotein, which downregulates E-cadherin and promotes metastasis. We studied the clinicopathological features in 72 cases of epithelioid sarcoma and in six cases of malignant rhabdoid tumor, and also assessed the immunohistochemical expression of dysadherin, E-cadherin and MIB-1 in epithelioid sarcoma and malignant rhabdoid tumor cases. In addition, we compared dysadherin mRNA expression between epithelioid sarcoma and malignant rhabdoid tumor cell lines, using RT-PCR and real-time quantitative RT-PCR analysis. Immunohistochemical dysadherin expression was more frequently observed in proximal-type epithelioid sarcoma (71%) in comparison with distal-type epithelioid sarcoma (36%) (P = 0.037). Furthermore, seven proximal-type epithelioid sarcoma cases mimicking malignant rhabdoid tumor (histologically classified as the large cell type, accompanied by frequent rhabdoid cells and located in deep soft tissue) were all positive for dysadherin (100%), whereas dysadherin expression was not detected at all in any of the true six malignant rhabdoid tumors (0%). Cell lines established from proximal-type epithelioid sarcoma revealed significantly higher levels of dysadherin mRNA expression, compared with the levels seen in malignant rhabdoid tumor cell lines by real-time quantitative RT-PCR (P = 0.0433). Epithelioid sarcoma patients with dysadherin expression survived for a significantly shorter time than those without dysadherin expression (P = 0.001). In multivariate analysis, dysadherin immunopositivity (P = 0.0004) was one of the two independent adverse prognostic factors. We conclude that dysadherin expression in epithelioid sarcoma is a significant poor prognostic factor and that it is a powerful diagnostic marker for distinguishing epithelioid sarcoma, including the proximal-type epithelioid sarcoma, from malignant rhabdoid tumor. In epithelioid sarcoma, especially in proximal-type epithelioid sarcoma, increased cell disadhesion and motility by dysadherin plays an important role to acquire aggressive biological behavior. However, in malignant rhabdoid tumor, cell growth cycle that is regulated by hSNF5/INI1 gene seems to be critical to lethal biological behavior rather than dysadherin.

Extrarenal rhabdoid tumors of soft tissue: Clinicopathological and molecular genetic review and distinction from other soft-tissue sarcomas with rhabdoid features

Malignant rhabdoid tumor (MRT) of the soft tissue is a rare and highly aggressive tumor that occurs in infancy or childhood. It predominantly involves a deep axial location such as the neck or paraspinal region. Microscopically, the tumor is composed of a diffuse proliferation of rounded or polygonal cells with eccentric nuclei, prominent nucleoli and glassy eosinophilic cytoplasm containing hyaline-like inclusion bodies, arranged in sheets and nests. These characteristic 'rhabdoid cells' are also present in certain soft-tissue sarcomas such as synovial sarcoma, extraskeletal myxoid chondrosarcoma and leiomyosarcoma. The existence of rhabdoid cells in these other sarcomas is correlated with a worse prognosis for the patients. Cytogenetic and molecular analyses have shown abnormalities in the long arm of chromosome 22 and alteration of the hSNF5/INI1 (SMARCB1) gene in renal, extrarenal and intracranial MRT. This gene alteration has been considered to be a specific molecular event in MRT, but a recent study has also demonstrated frequent alteration of this gene in proximal-type epithelioid sarcoma (ES). Both MRT of soft tissue and proximal-type ES show immunoreactivity for vimentin, cytokeratin and epithelial membrane antigen. The tumor cells of proximal-type ES are also occasionally positive for CD34 and beta-catenin, whereas MRT of soft tissue has no immunoreaction for these markers. Detailed clinicopathological and immunohistochemical evaluations are necessary to distinguish MRT of soft tissue from proximal-type ES, because these tumors demonstrated a similar morphology and the same gene alteration.

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.

Incidental Retrovesical “Proximal-Type” Epithelioid Sarcoma: Pitfall of Diagnosis

The article aims at presenting an uncommon case of retrovesically located “proximal-type” epithelioid sarcoma, incidentally found as a retrovesical mass during prostatectomy for benign prostatic hyperplasia. Clinical, pathological and immunohistochemical data are presented. More specifically, two transrectal ultrasounds (TRUS) revealed a prostate gland enhancement and no evidence of other pelvic masses. This case report underlines that the retrovesical location of this neoplasm may mislead from a correct clinical diagnosis.

Mesothelioma with rhabdoid features: an ultrastructural and immunohistochemical study of 10 cases

Mesotheliomas with rhabdoid morphology are rare and only two individual case reports have been documented in the literature. This author reports a series of 10 cases of mesotheliomas with rhabdoid features, nine of which originated in the pleura and one in the peritoneum. Eight of the patients were men and two were women. Six patients had a history of asbestos exposure. Histologically, seven of the mesotheliomas were epithelioid, two sarcomatoid, and one biphasic. The proportion of the rhabdoid cells seen in these cases constituted 15-75% of the individual tumors. Cytoplasmic staining in the rhabdoid cells was seen for pan-keratin and vimentin in all 10 cases, for keratin 7 in eight of eight, for calretinin in nine of 10, and for keratin 5/6 in seven of nine. Nuclear positivity for WT1 was observed in the rhabdoid cells of four of seven cases and membranous reactivity for mesothelin in four of six, and for podoplanin in two of six. Only one case showed desmin positivity in sparse cells in the nonrhabdoid component of the tumor. All of the cases were negative for CEA, MOC-31, TAG-72, CD15, CD34, bcl2, muscle-specific actin, and TTF-1. Ultrastructural studies revealed paranuclear collections of intermediate filaments, but no evidence of rhabdomyoblastic differentiation was seen. The mean survival of five of the six patients for whom this information was available was 3.8 months. The remaining patient had a survival time of 1 year. It is important for pathologists to be aware that mesotheliomas can present rhabdoid features, not only because they can be confused with other malignancies that can exhibit a similar morphology, but also because of their apparently unusually aggressive behavior. The value of immunohistochemistry and electron microscopy in the differential diagnosis of these tumors is discussed.

Epithelioid sarcoma in children and adolescents

BACKGROUND

Epithelioid sarcoma (ES) is an uncommon malignant soft tissue tumor. To the authors' knowledge, little information is available to date concerning its clinical features and management in children and adolescents, particularly with regard to the recently described proximal-type variant. The current study concerns 30 patients age<18 years who were enrolled in the Italian Soft Tissue Sarcoma Committee protocols.

METHODS

Histopathologic specimens, clinical data, and treatment modalities were reviewed for the current analysis. Nineteen patients had classic ES and 11 had proximal-type ES. Surgery was the mainstay of treatment; radiotherapy was given to six patients considered to be at risk of local disease recurrence due to incomplete resection, and chemotherapy was administered to eight patients.

RESULTS

With a median follow-up of 66 months, the 5-year event-free survival (EFS) and overall survival (OS) rates were 61.7% and 92.4%, respectively, but the OS rate dropped to 86.9% and 72.4%, respectively, at 10 years and 15 years. Local disease recurrence was the major cause of treatment failure. The most significant finding influencing both EFS and OS was tumor site, with a tumor location in the extremities predicting a favorable outcome. Initially unfavorable clinical findings and a worse outcome were associated with the proximal-type variant of ES. A response to chemotherapy was noted in three of the seven patients with measurable disease.

CONCLUSIONS

The current study confirms some typical features of ES (i.e., the peculiar superficial distal location [i.e., the hand, fingers], indolent growth, and a tendency to recur locally). The current study data do not clearly confirm the strong tendency for the lymph node involvement described in adult ES patients. Further studies are needed to better define the clinical behavior and biology of the proximal-type variant of ES.

Cutaneous extrarenal rhabdoid tumor with myogenic differentiation

BACKGROUND

The rhabdoid phenotype is characterized by large epithelioid cells with abundant eosinophilic cytoplasm and paranuclear inclusions of intermediate filaments. Although originally described in tumors from pediatric kidneys, the rhabdoid phenotype has since been described in a variety of patient ages and extrarenal sites. Extraordinarily, the rhabdoid phenotype has emerged in cutaneous neoplasms, either as a pure extrarenal rhabdoid tumor or a composite phenotype coupled with another malignancy. Regardless of the clinical setting, the rhabdoid phenotype is uniformly associated with aggressive biological behavior. We report the findings from a rare and very aggressive primary extrarenal rhabdoid tumor of the skin with myogenic differentiation.

CASE REPORT

A 53-year-old woman presented with an ulcerated nodule on her right medial calf and ipsilateral inguinal lymphadenopathy. Histological examination of the skin nodule as well as cytologic examination of a lymph node disclosed the characteristic rhabdoid phenotype. Electron microscopy demonstrated paranuclear globules of intermediate filaments; special stains suggested an underlying myogenic histogenesis. The patient was aggressively treated with chemotherapy but ultimately died of her disease 8 months after presentation.

CONCLUSIONS

The rhabdoid phenotype is rarely seen in cutaneous neoplasms, but when present, portends a poor prognosis adding particular importance to its recognition.

Epithelioid sarcoma: Still an only surgically curable disease

BACKGROUND

Epithelioid sarcoma is a rare soft tissue sarcoma with a known high propensity for locoregional recurrence and distant metastases. The clinical behavior and prognostic factors that influence the survival of patients with epithelioid sarcoma were studied.

METHODS

Twenty-three patients, including 16 men (70%) and 7 women (30%), who were treated for epithelioid sarcoma between 1979-2003 at the University Medical Center Groningen and Radboud University Nijmegen Medical Center, were reviewed retrospectively. The median age at diagnosis was 22 years (range, 1-54 years). At the time of diagnosis, 11 patients (48%) had metastases. Six patients with distant metastasis and 1 patient with an unresectable tumor received palliative treatment (30%). The remaining 16 patients underwent surgical treatment of local disease (11 patients) or locoregional disease (5 patients). Five patients in that group received isolated limb perfusion with tumor necrosis factor and melphalan.

RESULTS

The 5-year and 10-year disease-free survival rates for all patients were 34% and 17%, respectively; for the 16 patients who received curative treatment, both rates were 56%. In the latter group, 8 patients developed local recurrence (50%) after a median follow-up of 4 months (range, 1-14 months). Nine patients were disease free after a median follow-up of 50 months (range, 6-290 months). Tumor size >5 cm (P < .0026) at diagnosis and local recurrence (P < .0008) were significant predictors of survival.

CONCLUSIONS

The prognosis for patients with epithelioid sarcoma is poor, because a substantial number of patients present with extensive disease, lymph node metastases, and/or distant metastases. Treatment consists of radical surgical excision of the tumor and, if indicated, therapeutic lymph node dissection. In patients who have large tumors, isolated limb perfusion may be useful.

Proximal-Type Epithelioid Sarcoma: Report of Two Cases in the Perineum

The authors report two cases of perineal proximal-type epithelioid sarcoma in middle-aged men, age 51 and 43 years old. Both tumors were located in the right side. In the first patient a 7.5-cm, well-encapsulated tumor was completely excised. The second patient was a referral case with incomplete excision, but the computed tomography scan and magnetic resonance imaging showed a 14-cm nonencapsulated tumor involving the soft tissues of the inner thigh and perineum, as well as metastasis in right inguinal and retroperitoneal lymph nodes. Both neoplasms had a predominant solid pattern alternating with occasional discohesive areas. Both were composed of large oval to polygonal cells with vesicular nuclei, conspicuous nucleoli, and amphophilic to eosinophilic cytoplasm. Rhabdoid phenotype was identified in the second case only. The first neoplasm displayed 15% necrosis, 7 mitoses per 10 high-power field, focal vascular invasion, and no extracapsular invasion. The other exhibited 60% necrosis, 12 mitoses per 10 high-power fields, extensive vascular invasion, no distinct capsule, and invasion of the surrounding fatty tissue. Both were positive for vimentin, cytokeratin, epithelial membrane antigen, and CD34. Muscle-specific actin was negative in the first case and focally positive in the second. CD56 was positive in the second case and negative in the first case. Desmin, CD45, CD30, factor VIII, CD31, S100, HMB45, calretinin, and synaptophysin were negative in both. Since proximal-type epithelioid sarcoma can be confused with a number of other soft tissue tumors with epithelioid and/or rhabdoid features, the authors emphasize the immunohistochemical differential diagnosis.

Rhabdoid tumor of the thyroid gland: a variant of anaplastic carcinoma

Rhabdoid tumor of the thyroid gland is a very rare neoplasm, characterized by significant metastatic potential. All of the 6 cases reported in the recent literature had poor outcomes. We report an additional case involving, to our knowledge, the oldest patient reported so far. A 67-year-old woman had a nodular goiter for all of her adult life and presented with a rapidly growing mass in the right lobe. Histologic examination showed a highly cellular neoplasm with a solid infiltrative growth pattern. Extracapsular invasion was evident. Rhabdoid cells were large, with abundant cytoplasm, eosinophilic inclusions, and eccentric nuclei containing distinct nucleoli. Immunohistochemistry identified vimentin, sarcomeric actin, myoglobin, and cytokeratin expression in the tumor cells; they were negative for desmin, thyroglobulin, and calcitonin. Scattered follicles with nuclear features of papillary thyroid carcinoma were detected; these cells were immunoreactive for thyroglobulin and TTF-1. Reverse transcriptase polymerase chain reaction using specific primers for RET/PTC1 and RET/PTC3 fusion genes identified a RET/PTC3 gene rearrangement in the rhabdoid tumor. Despite radiotherapy, the neoplasm rapidly progressed, with massive local and mediastinal metastasis leading to death 5 months after presentation. The hypothesis that rhabdoid tumor is a variant of anaplastic thyroid carcinoma is supported by the identification of a RET/PTC gene rearrangement, a feature of carcinomas of follicular cell derivation.

Immunohistochemical analysis of a muscle ankyrin-repeat protein, Arpp, in paraffin-embedded tumors: evaluation of Arpp as a tumor marker for rhabdomyosarcoma

Arpp, a protein including an ankyrin-repeat, P EST motif, and p roline-rich region, is a recently identified protein that is exclusively expressed in striated muscles. This study comprehensively analyzed its expression among soft tissue sarcomas of various histological types and evaluated its potential use for the differential diagnosis of rhabdomyosarcoma (RMS). Formalin-fixed, paraffin-embedded tissues, including 37 RMS cases, 88 non-RMS sarcomas, and 38 carcinomas, were analyzed for Arpp expression. Arpp was detected in 33 (89.2%) of 37 RMS cases by immunohistochemistry. Western blot analysis revealed expression of Arpp in all RMS cases tested. High expression of Arpp was generally associated with morphological evidence of skeletal muscle differentiation of tumor cells. In contrast, Arpp displayed 6.3% (8/126) positivity among the non-RMS tumors. Focal or weak expression was seen in malignant fibrous histiocytoma (2/27), synovial sarcoma (1/11), Ewing sarcoma (1/5), and epithelioid sarcoma (3/5), whereas one epithelioid sarcoma displayed strong expression for Arpp. A comparative analysis of the Arpp profile with that of myogenic markers in RMS revealed that the sensitivity of Arpp (89.2%) was higher than that of myoglobin (59.6%) and comparable with that of myogenin (88.2%), MyoD (80.6%), muscle-specific actin (83.8%), and desmin (89.2%). These results suggested that Arpp is sensitive to and specific for RMS. Thus, we proposed that Arpp is a novel skeletal muscle-specific marker, which is useful for differential diagnosis of RMS.