Epithelioid sarcoma in children and adolescents. An immunohistochemical study

Classic Type of Epithelioid Sarcoma of the Distal Upper Extremity: Clinical and Oncological Characteristics

BACKGROUND

The classic type of epithelioid sarcoma (ES) is a rare, aggressive soft tissue neoplasm that most commonly affects the distal upper extremities of young patients. This study aimed to assess clinical features and provide a long-term report of the oncological outcome.

METHODS

We retrospectively analyzed our clinical database for patients with ES of the distal upper extremities.

RESULTS

Twenty-three patients with ES of the distal upper extremity were treated surgically between January 1990 and August 2018. ES affected most commonly the palmar side of young patients. The most common site affected by a sarcoma was the wrist in 47.8% of cases, followed by metacarpals and fingers with 34.8% and 17.4%, respectively. Most of the patients were treated according to the protocols of interdisciplinary tumor boards with multimodal therapy. A local recurrence was observed in 7 patients (30.4%). The 5 - and 10-year recurrence-free survival was 80.4% (95% confidence interval [CI]: 68.6-76.8) and 60.9% (95% CI: 53.5-68.3), respectively. The 5- and 10-years disease-specific survival was 89.9% (95% CI: 87-92.8) and 61.9% (95% CI: 56.5-67.3), respectively. Five patients (21.7%) had metastasis in regional lymph nodes.

CONCLUSION

The classic type of ES represents a group of high-grade sarcomas, which affect the dominantly distal upper extremity. Specific clinical, diagnostic, and oncological characteristics make it difficult to diagnose and therapy. Wide tumor resection as a part of multimodal therapy remains a more viable and common treatment option for patients with ES on distal extremities. High rates of lymph node metastasis are typical for ES.

Distal-type epitheloid sarcoma mimicking a wart in a child: A diagnosis not to be missed

Epithelioid sarcoma is a rare soft-tissue tumor that occurs mainly in children and young adults. It typically presents as a subcutaneous or deep dermal mass in distal extremities. Due to its benign-appearing clinical presentation, infrequent occurrence, and histologic similarities with other pathologies, the diagnosis of epithelioid sarcoma in its early stages can be extremely difficult and can be easily confused with benign lesions such as warts or foreign body granuloma. In this paper, we report the case of a 12-year-old boy with a distal-type epithelioid sarcoma of the hand and wish to emphasize the difficulties of diagnosing this potentially lethal tumor both clinically and histologically.

Prognostic Value of Relevant Clinicopathologic Variables in Epithelioid Sarcoma: A Multi-Institutional Retrospective Study of 44 Patients

Background

Epithelioid sarcoma (ES) is an extremely rare soft tissue sarcoma. Recently, the proximal variant has been reported to be a more aggressive subtype; however, as most reports of ES have involved small case series, the actual prognostic implications remain unclear. We investigated the clinicopathological features of patients with ES to identify the prognostic factors that influence survival.

Methods

We retrospectively analyzed the clinicopathological features of 44 patients with ES who had been treated at our institutions between 1991 and 2011. Among these patients, 26 were diagnosed histologically as having classic-type ES, whereas the remaining 18 had proximal-type ES. Thirty-three of the patients, all without distant metastases, underwent curative surgery, and the remaining 11 with distant metastases (M1) received palliative treatment.

Results

The proximal subtype was significantly correlated with a proximal tumor location, distant metastases at presentation, presence of rhabdoid cells, a higher tumor grade, and vascular invasion. The overall survival (OS) rate at 5 years for the 44 patients was 45 %. A superficial tumor location and lymph node metastases (N1) at presentation were independently predictive of local recurrence-free survival (LRFS), and N1 and M1 tumors were independently predictive of distant metastasis-free survival and OS, respectively. The proximal subtype was associated with unfavorable LRFS and OS, although not to a statistically significant degree.

Conclusions

Proximal-type ES has significantly more aggressive clinicopathological features than classic-type ES, and lymph node or distant metastasis has the most critical impact on prognosis.

Soft tissue tumors of uncertain origin

Many soft tissue tumors of childhood lack obvious differentiation toward a defined mesenchymal tissue type or have a phenotype that does not correspond to any defined normal tissue. These challenging tumors are currently regarded as neoplasms of uncertain differentiation. Nonetheless, there have been great strides in the understanding of their pathologic and genetic features and biologic underpinnings. The application of new genetic information to the pathologic diagnosis among this group of tumors is an emerging area in diagnostic pediatric pathology. This article reviews the clinicopathologic features of tumors of uncertain and/or miscellaneous origin, with an emphasis on the unique aspects of these neoplasms in children and adolescents, use of diagnostic adjuncts, and differential diagnosis.

Proximal-type epithelioid sarcoma of the vulva with INI1 diagnostic utility

Proximal epithelioid sarcoma (PES) is an extremely uncommon neoplasm of the vulva with an aggressive behavior. Recently, these authors experienced a case of proximal-type ES in a 41-year-old woman who was admitted for a rapidly growing mass in the right mons pubis. An about-1-cm-sized mass was initially noticed one and a half years earlier. The excised mass, however, was 8 cm in greatest dimension and was relatively well circumscribed. The cut surface was trabeculated, with multifocal hemorrhages and necroses. Microscopically, the tumor consisted of epithelioid rhabdoid cells with vesicular nuclei, large prominent nucleoli, and cytoplasmic eosinophilic globules comparted by thin, fibrous septae. The main differential diagnoses included PES, other sarcomas with epithelioid cells, malignant melanoma, and sarcomatoid carcinoma. The tumor cells were diffusely positive for vimentin and EMA; focally positive for cytokeratin; and negative for CK5/6, CD34, S-100 protein, desmin, and myogenin. INI1 (hSNF5/SMARCB1, a member of the SW1/SNF chromatin remodeling complex located on chromosome 22q11.2) staining clearly showed loss of expression in the tumor cells. Recent studies reported that some ESs also showed INI1 inactivation, as characteristically seen in malignant rhabdoid tumors of infancy. Reported herein is the diagnostic utility of INI-1 on PES and the possible relationship between PES and malignant rhabdoid tumor of the soft tissue, besides a collective review of the reported cases of PES of the vulva and of the current case.

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.

Application of immunohistochemistry to soft tissue neoplasms

CONTEXT

Soft tissue tumors are composed of numerous and complex diagnostic entities. Because of this complexity and the recognition of an intermediate malignancy category including some tumors with a deceptively bland histologic appearance, soft tissue tumors may represent a major diagnostic challenge to the general practicing pathologist.

OBJECTIVE

To correctly diagnose soft tissue tumors with the ancillary use of immunohistochemistry.

DATA SOURCES

Review of the current literature with emphasis on those tumors for which immunohistochemistry has proven to be particularly useful.

CONCLUSIONS

Immunohistochemistry plays an important role in the diagnosis of soft tissue tumors. One of its major utilities is to correctly identify a tumor as being of mesenchymal or nonmesenchymal origin. Once mesenchymal origin has been established, histologic subtyping according to specific cell lineage may be achieved with the use of lineage-specific markers. Tumors of uncertain cell lineage and tumors with primitive small round cell morphology are often characterized by a unique immunohistochemical phenotype. In this group of tumors, immunohistochemistry is most widely applied and is of greatest value. Despite the rapid development of molecular genetic techniques, immunohistochemistry still remains the most important diagnostic tool in the diagnosis of soft tissue tumors aside from recognition of morphologic features and clinical correlation.

Epithelioid sarcoma arising on the forearm of a 6-year-old boy: case report and review of the literature

Epithelioid sarcoma is a rare malignant tumor that occurs mainly in young adults and most frequently involves the distal portion of the upper extremities. The tumor is particularly rare in children and more frequently involves the head and neck; only one case involving the forearm has been reported in a child under 10 years of age, and he was treated with amputation. We report the case of a 6-year-old boy with an epithelioid sarcoma of the forearm whose initial management had been inappropriate. The patient was ultimately treated with limb sparing surgery. Two years later, no local recurrence was evident but pleural metastases were detected.

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.

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.

Primary giant cell tumor of soft tissue

BACKGROUND

Primary giant cell tumor of soft tissue, also known as soft tissue giant cell tumor of low malignant potential, is a rare soft tissue tumor located in both superficial and deep soft tissue. Histologically, these lesions bear a close resemblance to their bony counterparts, giant cell tumor of bone, with round to spindle-shaped cells intimately admixed with uniformly scattered osteoclast-like multinucleated giant cells. In 1989 in the dermatology literature, two malignant giant cell tumors of soft parts were described that filled the dermis and extended into the subcutaneous tissue.

METHODS

The authors report the rare occurrence of a giant cell tumor of soft tissue occurring primarily in the dermis that lacks overtly malignant features and clinically was thought to be an epidermal inclusion cyst.

RESULTS

Light microscopy revealed a non-encapsulated cellular dermal tumor containing numerous osteoclast-like giant cells. Cytologic atypia was minimal and the mitotic count averaged 2-3/10 HPF. The histologic differential diagnosis is also discussed.

CONCLUSION

Giant cell tumor of soft tissue is a rare neoplasm of the skin, however, recognition of this tumor is important due to its behavior as a low-grade malignancy.

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.

Proximal-type epithelioid sarcoma in the pelvic soft tissues

A case of proximal-type epithelioid sarcoma arising in the pelvic soft tissues of a 46-year-old man is presented. The tumor showed a predominantly epithelioid component with rhabdoid features, cord-like arrangement, small nests, abundant eosinophilic cytoplasm containing intracytoplasmic, paranuclear, hyaline-like globules, large vesicular nuclei, and prominent nucleoli. There were foci with alveolar arrangement and a spindle-cell proliferation. The tumor cells were positive for cytokeratin CAM5.2, vimentin, epithelial membrane antigen, and CD34. Flow cytometry showed a diploid DNA content with high S-phase fraction. The patient had pelvic lymph-node metastases. He died of the disease 5 months after diagnosis. It is important to include proximal-type epithelioid sarcoma in the differential diagnosis of pelvic tumors.

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.

"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.

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 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. Flow cytometric study of DNA content and regional DNA heterogeneity

The DNA content and regional DNA heterogeneity in correlation with clinicopathologic parameters and patient survival were investigated in epithelioid sarcoma. Such neoplasms preponderantly manifest diploid DNA content and a remarkably stable intratumoral and intertumoral DNA content. Small tumor size (less than 5.0 cm) and low S-phase fraction (less than 5%) were significant prognostic factors in this study. Ploidy status, mitotic rate, age, and postsurgical treatment were not significantly correlated with survival.

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.

Extrarenal primitive malignant tumor with rhabdoid features: fine-needle aspiration cytology, immunocytochemistry, and electron microscopy of a case

We describe a malignant pelvic tumor with rhabdoid-like features that arose in the sacroiliac region of a 15-year-old girl. Fine-needle aspiration (FNA) cytology showed large cells with glassy cytoplasm, globular hyaline cytoplasmic inclusions, and prominent nucleoli. Immunocytochemical methods applied to FNA material revealed immunoreactivity for cytokeratin, epithelial membrane antigen, and vimentin; the cells failed to react with antibodies to desmin. This distinct appearance and phenotype was most consistent with a diagnosis of extrarenal malignant rhabdoid tumor. Electron microscopy confirmed this interpretation, showing whorled filamentous aggregates in the cytoplasm of the tumor cells.

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.

Cytokeratin expression in epithelioid vascular neoplasms

Seven epithelioid and eight non-epithelioid vascular tumors were studied by the avidin-biotin-peroxidase method for the presence of endothelial- and epithelial-associated markers, using Ulex europaeus agglutinin-1 (UEA-1) lectin, and antibodies directed against factor VIII-related antigen, (FVIII-RA), vimentin, keratin, carcinoembryonic antigen, and epithelial membrane antigen. The cases included four epithelioid hemangiomas, two epithelioid hemangioendotheliomas (EHE), one epithelioid angiosarcoma (EAS), four common non-epithelioid capillary hemangiomas, and four non-epithelioid angiosarcomas. Staining for FVIII-RA, UEA-1, and vimentin were observed in all cases. The EAS showed staining for keratin in formalin-fixed, paraffin-embedded sections and in frozen sections. Staining for keratin was also observed in frozen sections of one EHE. Both keratin-positive vascular tumors were confirmed with electron microscopy. Carcinoembryonic antigen and epithelial membrane antigen stains were negative in all cases. Our results show that the epithelioid vascular tumors EHE and EAS, in addition to staining for the endothelial markers and vimentin, may also express the epithelial marker keratin. This is important since these tumors may closely resemble carcinomas by routine light microscopy. This study further underscores the importance of using a broad panel of immunohistochemical markers in the diagnostic workup of soft-tissue neoplasms.

Multidirectional differentiation in a newly established human epithelioid sarcoma cell line (GRU-1) with co-expression of vimentin, cytokeratins and neurofilament proteins

A new permanent cell line (GRU-1) derived from the lymph-node metastasis of a human epithelioid sarcoma was established in tissue culture. Immunohistochemically, the original tumor had exhibited an intriguing potential for multidirectional differentiation with features of mesenchymal, epithelial and neural differentiation, evidenced by the co-expression of vimentin, cytokeratins and neurofilament proteins, respectively. This capability for multidirectional differentiation was fully preserved in the cultured cells. GRU-1 tumor cells proved to be uniformly positive for vimentin and a considerable proportion of the tumor cells exhibited a positive reaction for cytokeratins and neurofilament proteins. The neural markers neuron-specific enolase (NSE) and synaptophysin were observed in a small proportion of GRU-1 cells. Ultrastructurally, GRU-1 cells showed desmoplastic activity in vitro, being enmeshed by collagen fibrils. DNA distribution, as studied by flow cytophotometry, revealed DNA-diploidy (DNA index = 1) and a G0/G1-proportion of 70.5%. After heterotransplantation in nude mice, GRU-1 tumor cells expressed vimentin and cytokeratin only, whereas the neural markers could not be further demonstrated.

Prolonged pyrexia and lung metastases. A rare presentation of an occult epithelioid sarcoma

A 31-year-old patient presenting with fever of unknown origin, night sweats and weight loss, associated later with pulmonary nodules, is described. Multiple invasive diagnostic procedures, including exploratory laparotomy and open-lung biopsy, suggested a benign inflammatory granulomatous disease. Metastatic epithelioid sarcoma was ultimately diagnosed after biopsy of an enlarging groin mass. Epithelioid sarcoma should be considered in the differential diagnosis of prolonged fever, associated with granulomas of obscure etiology.

Glial fibrillary acidic protein and keratin expression by benign and malignant nerve sheath tumors

Formalin-fixed, paraffin-embedded sections of 59 ultrastructurally confirmed nerve sheath tumors (NSTs) that included 27 benign schwannomas, five neurofibromas, and 27 malignant schwannomas were studied by the avidin-biotin-peroxidase complex method using antibodies directed against glial fibrillary acidic protein (GFAP), keratin, S-100 protein, vimentin, and desmin. GFAP was expressed by 33% of the benign schwannomas, 40% of the neurofibromas, and 7% of the malignant schwannomas. Keratin was expressed by 7% of the benign schwannomas and 4% of the malignant schwannomas. S-100 protein was expressed by 100% of the benign NSTs and by 40% of the malignant schwannomas. Vimentin was observed in 100% of the benign NSTs and in 85% of the malignant schwannomas. None of the cases stained for desmin. GFAP and cytokeratin expression could not be predicted on the basis of tumor light microscopy or ultrastructure. These findings are of practical importance in routine surgical pathology, particularly with respect to the differential diagnosis of gliomas located in the central nervous system and in immunohistochemical studies of peripherally located, poorly differentiated neoplasms.

Epithelioid sarcoma

Epithelioid sarcomas are histogenetically and often biologically peculiar soft tissue malignancies that may be either primary or metastatic in the head and neck. The sarcomas have high recurrence and metastatic rates and a sometimes torpid course but nonetheless poor survival.

Epithelioid sarcoma or malignant rhabdoid tumor of soft tissue? Epithelioid immunophenotype and rhabdoid karyotype

Two children and one young adult with extremity sarcomas demonstrating an aggressive clinical behavior are described. Histologically, all three tumors displayed features compatible with a deep-seated epithelioid sarcoma or with a malignant rhabdoid tumor of soft tissue. Immunohistologically, both vimentin and epithelial antigens were demonstrated; however, no desmin was detectable. In all three cases, the DNA profile was diploid. In one case, a trisomy of chromosome 2 was found in the tumor cells, a phenomenon also observed in embryonal rhabdomyosarcomas. It is concluded that, although the immunohistologic findings support the epithelioid character of the tumors, this chromosomal finding suggests a relationship with rhabdomyosarcomas and justifies the designation of rhabdoid.

Malignant rhabdoid tumor. A morphological and flow cytometric study

Sixteen cases of malignant rhabdoid tumor (MRT) were studied by conventional light microscopy, immunohistochemistry, electron microscopy and flow cytometry. The age of the 16 patients varied from two months to 25.9 years. There were 11 males and five females. Eleven tumors were located in the kidney. The remaining five were found in the chest wall (n = 2) and the head and neck (n = 3). Particular histopathological findings included myxoid, pseudoalveolar and hyalinized areas. By immunohistochemistry, 15/15 cases stained positively for vimentin, 9/14 for cytokeratin, 6/15 for desmin, 9/14 for epithelial membrane antigen (EMA), 10/14 for neuron specific enolase (NSE) and 10/15 for protein S-100. Stains for neurofilaments, myoglobin and Ulex europaeus aggl. I (UEA I) were negative. The characteristic finding by electron microscopy in three cases were large numbers of intermediate filaments arranged either randomly or in concentric whorls. None of the 11 cases studied revealed aneuploid DNA stem lines as determined by flow cytometry. Of the 16 patients 12 died, one is living with disease and three are living without evidence of disease. Postoperative treatment consisted of chemotherapy, in some cases combined with radiotherapy. Two patients developed a medulloblastoma in addition to a renal and extrarenal MRT, respectively. Our findings demonstrate that MRT may present more histopathological patterns than hitherto recognized. In addition, they show that MRT may express a wide range of antigenic "markers", similar to epithelioid sarcoma with which it may be confused on cytological grounds. Despite aggressive postoperative chemotherapy prognosis is still poor.

Epithelioid sarcoma in children and adolescents: a report of four cases

Epithelioid sarcoma is an uncommon soft tissue tumor, most prevalent in the extremities of young adults. Youth has been described as a favorable prognostic factor. We describe four patients (two children aged 10 years and two adolescents aged 18 years) with extremity epithelioid sarcoma. Both 10-year-old children had rapid disease evolution and died 3 and 6 months after the diagnosis was made. Both tumors were strict diploid at DNA flow cytometry, but one had an abnormal karyotype (trisomy 2). Both adolescents are disease-free 18 months and 18 years after combined treatment consisting of local resection, regional lymph node dissection, and isolated regional perfusion with cytostatic agents.

Epithelioid sarcoma: the spectrum of ultrastructural differentiation in seven immunohistochemically defined cases

Seven epithelioid sarcomas were examined by light and electron microscopy and by immunohistochemical methods for the presence of vimentin and the epithelial markers keratin and epithelial membrane antigen. All the tumors displayed vimentin and both epithelial markers. Electron microscopy showed a spectrum of cellular differentiation from primitive fibrohistiocytic cells to epithelial-type cells with junctions, microvilli, and tonofilaments. Spindle cells showed myofibroblastic and fibroblastic differentiation. Epithelioid sarcoma appears to be a tumor of primitive cells with the potential for mesenchymal and epithelial differentiation, like some embryonic tumors.