Epithelioid sarcoma: ultrastructural similarity to nodular synovitis

Treatment and outcomes of epithelioid sarcoma of the spine

Epithelioid sarcoma (ES) is a rare soft-tissue neoplasm which is most commonly found in the extremities of young adult males. ES has a poor prognosis due to its aggressiveness as it frequently recurs locally and can undergo lymphatic metastasis to soft tissue, fascia, bone, lymph nodes, lung, and brain. The most common form is the classic-type (granuloma-like), though a more aggressive subtype known as the proximal- or axial-type has also been described. As ES of the spine is exceedingly rare, with only seven patients being reported in the literature, the outcomes of these patients is unclear. We have reviewed the literature of all existing spinal ES cases to recommend treatment strategies and report the first case of proximal-type ES in the cervical spine. Patients with spinal ES had an average age of 20.7 years, with 71.4% of cases being in males. Metastasis was common and was found in 83.3% of patients, with lung metastasis being found in 60% of these patients. Due to the high rates of local recurrence and distant metastasis, the goal of surgery remains gross total resection of all tumor and involved bony elements if feasible without significant neurological deficits. Ligation of involved nerve roots may be necessary to achieve adequate resection of the tumor mass as nerve sheaths can serve as a pathway for extension. In the cervical spine, resection of these lesions is difficult due to involvement of the vertebral arteries in addition to nerve roots, increasing the surgical risk.

Epithelioid sarcoma in the thoracic spine

Epithelioid sarcoma is a rare and highly malignant soft tissue tumor that is commonly found in the extremities and rarely in the trunk area. This malignant tumor often mimics granuloma or nodular fasciitis, which causes a delay in establishing the diagnosis. This type of cancer has a high recurrence rate. Surgical treatment requires wide radical resection. The objective of this case report is to highlight the unique location of a rare neoplasm and to illustrate the relentless course of epithelioid sarcoma despite initial radical resection. A 14-year-old boy was admitted to our facility with a soft tissue mass on the right lower thoracic spine. The large tumor mass had deeply penetrated into the muscles, infiltrated the neuroforamen of T9–T10 level, and compressed the dural sac. Immunohistological study of the biopsy was highly consistent with an epithelioid sarcoma. Wide excision of the mass, laminectomy and spine fusion with instrumentation was performed. The patient received chemotherapy and irradiation. The first recurrence of the neoplasm was seen as a contralateral metastasis 21 months after the resection. On the last follow-up, 3 years postoperatively, the patient was in a good general condition. However, further progression of the sarcoma had to be recognized. Our case encompasses multiple features that represent negative prognostic factors. Initial wide excision of the neoplasm and adjuvant therapy including chemotherapy and irradiation seem to slow down the relentless course of epithelioid sarcoma in the trunk.

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.

Vulvar epithelioid sarcoma in pregnancy

BACKGROUND

Epithelioid sarcoma is a soft tissue tumor rarely found centrally and even less commonly on the vulva. Vulvar sarcoma in pregnancy is also exceedingly rare with only five cases reported to date, none of which have been an epithelioid sarcoma.

CASE

We report a case of a 29-year-old woman presenting with a vulvar epithelioid sarcoma at 36 weeks of gestation. The patient underwent a radical resection 6 weeks postpartum followed by chemotherapy. Despite a radical hemivulvectomy and doxorubicin and ifosfamide chemotherapy, she developed pulmonary metastasis and died of tumor-related pulmonary failure secondary to her disease 612 months after diagnosis. To our knowledge this is the first case of a vulvar epithelioid sarcoma presenting during pregnancy. The English literature is reviewed and a total of 18 previous cases of vulvar epithelioid sarcoma have been reported outside of pregnancy. Insight into the biological behavior and therapeutic management of this disease is discussed.

CONCLUSION

The optimal management of vulvar epithelioid sarcoma remains to be determined. However, it would seem that early and aggressive surgical resection provides the best possibility for cure. The role of radiation and/or chemotherapy remains to be determined.

Epithelioid sarcomas. Three cases

The authors present two cases of epithelioid sarcoma of the hand and one of the foot with clinical interest. This recently described tumor (Enzinger, 1970), is relatively rare. It occurs in the hand, forearm, pretibial region and foot and affects principally young adults. It should be emphasized, and this is borne out in the literature, that this tumor may appear perfectly benign and often has a course of long duration. The difficult of clinical and especially of histologic diagnosis as well as the difficulty of determining the boundaries of extension of the tumor makes it necessary to carry out radical surgery (amputation or rarely block excision). Every author agrees that local excision is to be condemned, there being an 85% recurrence rate. Spread of the tumor is by way of the fascial planes and tendon sheaths. Lymphatic and pulmonary metastases occur particularly when there is vascular invasion.

Epithelioid sarcoma

Epithelioid sarcoma is a malignant soft tissue tumor characterized by its propensity to occur in the distal extremities as a nodular lesion and its slow and asymptomatic growth. Microscopically, the diagnosis is difficult. Therefore the interval between onset of symptoms and diagnosis averages one to three years. 10 years survival after onset are not uncommon whatever the treatment chosen. Having to treat such a tumor of a hand, 8 years after onset, we decided a local radical excision by micro-surgery instead of amputation or mutilating excision. Long standing clinical follow-up will add valuable information as to the cure of the upper extremity.

Epithelioid sarcoma of the spine: a case report

STUDY DESIGN

This case report illustrates a patient presenting with sciatica and diagnosed with epithelioid sarcoma involving the spine.

OBJECTIVES

The treatment of this patient involved multiple mass resections and decompressions of the spinal canal. Radio- and chemotherapy were applied once a clear diagnosis was obtained.

SUMMARY OF BACKGROUND DATA

Epithelioid sarcoma is a rare tumor mainly arising in the extremities. Confusion with a benign inflammatory process are possible. Treatment after histologic diagnosis involves wide resection. To our knowledge, this report represents the first case of epithelioid sarcoma involving the spine.

METHODS

After initial discectomy, recurrent scarring and mass formation required multiple decompression procedures and fusion. The initial pathology revealed inflammatory reaction on fibrosis. In a later procedure, the histologic diagnosis of epithelioid sarcoma was made. Radiotherapy and chemotherapy were begun immediately.

RESULTS

Despite aggressive resections, radiotherapy, and chemotherapy, the patient died 3 months after the last surgical procedure.

CONCLUSION

Spinal epithelioid sarcoma can be mistaken for a benign inflammatory process. After a histologic diagnosis, aggressive wide resection is necessary. Multiple recurrences are documented with this tumor in other sites. Prognosis in trunk involvement is less favorable than involvement of the extremities. The role of adjuvant radio- and chemotherapy is unclear for spinal involvement.

Morphological characterization of a new human epithelioid sarcoma cell line, ES020488, in vitro and in vivo

A new human epithelioid sarcoma cell line (ES020488) was established from a cutaneous metastasis in 26-year-old man, and was morphologically characterized in vitro and in vivo by comparison with the original tumor. The ES020488 cells showed a male karyotype ranging from 39 to 83 chromosomes, with various abnormalities but no specific pattern. The cells were round, polygonal or spindle-shaped with abundant cytoplasm and round nuclei containing prominent nucleoli; they proliferated in a sheet-like pattern. Tumors transplanted into nude mice revealed essentially the same features as the original tumor. Both in vitro and in vivo, the cells immunohistochemically expressed vimentin, cytokeratin, and EMA, but not desmin and S-100 protein. Ultrastructural study revealed irregular or round nuclei containing abundant euchromatin and prominent nucleoli, many intermediate filaments running irregularly or around the nucleus, and a number of filopodia-like processes. ES020488 cells were thus proven to retain and exhibit the unique morphological characteristics of an epithelioid sarcoma both in vitro and in vivo. These cells are possibly derived from synovioblastic mesenchyme.

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.

The fibroma-like variant of epithelioid sarcoma

Five cases of a previously undescribed variant of epithelioid sarcoma are presented. This variant differs from the usual lesion in its absence of the typical necrobiotic nodular epithelioid pattern. It is instead composed of deceptively bland fibrohistiocytic and myoid cells arranged in a fibroma-like or dermatofibroma-like pattern with an affinity for osseous involvement. The clinical presentation, ultrastructural features, and presence of vimentin and low molecular weight keratin within the tumor cells justifies their designation as an epithelioid sarcoma variant.

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.

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.

Soft tissue sarcomas

Soft tissue sarcomas in infants and children differ from those in adults in clinical presentation, histology, and response to therapy. For rhabdomyosarcoma, the most common sarcoma in children, each primary site has special characteristics that affect both treatment programs and survival rates. Some results are so good, from the standpoint of survival data, that studies are now in progress to evaluate means of reducing treatment morbidity. Other ongoing studies focus on improved protocols for metastatic or recurrent rhabdomyosarcoma. Results thus far in the IRS trials have proven the value of cooperative clinical trials in the management of patients with this disease.

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.

Cellular junctions in a spectrum of human malignant tumors

Cellular junctions in tumors are often considered a hallmark of epithelial differentiation. However, junctions are also seen in tumors having a different differentiation. This observation prompted us to study cellular junctions in malignant nonepithelial tumors. We found a variety of cellular junctions in such tumors, although the majority were poorly formed. This observation is of importance for diagnostic purposes. We have also tried to clarify the nomenclature of cellular junctions as applied in tumor diagnosis by proposing a systematic categorization of terms in everyday use by pathologists and by referring more extensively to the term paired subplasmalemmal densities (PSD) for non-well-formed junctions.

Epithelioid sarcoma in children and adolescents. An immunohistochemical study

Six cases of epithelioid sarcoma were studied by conventional light microscopy and immunohistochemistry. The six cases account for 1.4% of the 417 cases of soft tissue sarcoma collected at the Paediatric Tumor Registry, Kiel. The average age of the five male and one female patient was 10.8 years (median: 13 years). Particular clinical findings included the location of the tumours; three were found in the pelvis, two in the head and neck, and one in the hand. Four patients are living without disease, and one patient died of disease three years after diagnosis. Histologically, four of the six tumours revealed multinucleated giant cells. Immunohistochemically using a panel of mono- and polyclonal antibodies all cases stained positively for vimentin, cytokeratin, epithelial membrane antigen (EMA), and human milk fat globulin (HMFG-2). Five cases were positive for neuron specific enolase (NSE), and three stained positively for protein S-100. A positive reaction for alpha-1-antichymotrypsin was noted in two cases. These immunohistochemical findings attest to the multidirectional differentiating capabilities of epithelioid sarcoma and support the concept of derivation from a multipotent mesenchymal stem cell.

Epithelioid sarcoma of penis

A case of epithelioid sarcoma of the penis in a thirty-two-year-old man is presented. It had been present for two and one-half years as a small nodule on the ventral aspect at the base of the penis that eventually grew to large dimensions causing pain and extreme dysuria. A local resection was done; however, when tumor recurred, penectomy was undertaken followed by an incomplete course of radiotherapy. Fifteen months after surgery the patient was free of local recurrence but was in poor condition with metastases to regional and distant lymph nodes, lungs, and scalp--a pattern of spread characteristic of these tumors. This is a typical example of epithelioid sarcoma clinically, histologically, and ultrastructurally, despite the rare location.

A unified hypothesis for the histogenesis of the soft tissue sarcomas of unknown origin

At the present time there is still a group of soft tissue sarcomas with an unknown origin. These occur most frequently in the extremities and include the following sarcomas: clear cell, alveolar, synovial, epithelioid, chordoid and small round cell. Most of the studies directed to find their histogenesis are based on finding similarities between normal embryonic or mature tissues of the tenosynovial region and these tumors at the ultrastructural and immunohistochemical level searching for specific markers. In this sense, the results are confusing and the common or different cells responsible for these sarcomas have not yet been isolated. In the present hypothesis it is proposed that the common progenitor of these malignancies is an ectomesenchymal derived tissue related to the tendons, aponeuroses, synovia and menisci called chondroid tissue or pseudocartilage; the evolutionary reasons that support this hypothesis are also discussed here. This also emphasizes the possibility that these sarcomas originate in phylogenetic mature remains and not in the reactivation of embryological cellular groups (Cohnheim's theory).

Distribution of collagen type IV in soft tissue tumors. An immunohistochemical study

The distribution of collagen type IV, one of the major constituents of basement membrane, was studied immunohistologically in a series of 103 soft tissue tumors including those of peripheral nerve origin, smooth muscle origin, striated muscle origin, fibrous tissue origin, fibrohistiocytic origin, adipose tissue origin, synovial tissue origin, and blood vessel origin, paragangliomas, alveolar soft part sarcomas, granular cell tumors, and epithelioid sarcomas. Intensely positive staining for collagen type IV was observed in neurilemomas, neurofibromas, malignant schwannomas, and blood vessel tumors. Weakly to moderately positive staining was seen in leiomyomas, angiomyomas, and leiomyosarcomas. In contrast, synovial, fibroblastic and fibrohistiocytic tumors, benign or malignant, were negative. In paragangliomas, granular cell tumors, and alveolar soft part sarcomas, positive staining was evident surrounding nests or clusters of tumor cells. In all tumors, staining for collagen type IV clearly illustrated the vascular pattern.

Functional limb salvage with multimodality treatment in epithelioid sarcoma of the hand: a report of two cases

Two cases of epithelioid sarcoma in the hand are reported. The first presented as a space-occupying lesion causing carpal tunnel syndrome, which has not been previously reported. The second case presented with a tumor in the palm that was initially misdiagnosed as a benign tumor and was treated inadequately and recurred. With treatment consisting of surgical excision, adjuvant local radiotherapy, and pulsed systemic chemotherapy combined with early detection and aggressive treatment of distant metastases, both patients have functional hands without local recurrence. They are presently free of obvious disease and remain under close observation at short follow-up of 6 and 4 years, respectively.

Immunohistochemistry of soft tissue tumours: a review

The diagnosis and classification of soft tissue sarcomas can pose difficult problems for the histopathologist. Many sarcomas are too poorly differentiated to exhibit morphological features specific enough to define their histogenesis. Using the immunoperoxidase technique with commercially available antisera as a routine adjunct to other diagnostic aids, it is possible to arrive at more accurate diagnoses on which treatment protocols can be based. In addition a better understanding of mesenchymal neoplasms and their origins can be obtained by functional immunohistochemical studies.

Epithelioid sarcoma of the vulva. Evidence suggesting a more aggressive behavior than extra-genital epithelioid sarcoma

The authors describe two cases of epithelioid sarcoma of the vulva and summarize the clinical and pathologic experience with this vulvar neoplasm. Findings indicate that epithelioid sarcoma of the vulva usually occurs in the labia majora of young women, but may occur in later life. Clinically it may mimic a Bartholin's duct cyst, thus leading to inadequate treatment. Pathologic findings are characterized by sheets and nests of acidophilic, polygonal cells. Follow-up study suggests that vulvar epithelioid sarcoma behaves more aggressively than extragenital epithelioid sarcoma. Four of five patients died of metastatic sarcoma. The courses of three patients were quite rapid, whereas a fourth patient had multiple recurrences over a long period, which is typical of extragenital epithelioid sarcoma. Complete initial excision is important. All patients with local recurrence died with distant metastases. Vascular invasion also indicates a poor outcome.

Epithelioid sarcoma: a tumour of myofibroblasts

A case of epithelioid sarcoma of scalp has been studied by light and electron microscopy, histochemistry and immunocytochemistry. The results suggest that epithelioid sarcoma is a tumour of myofibroblasts. The epithelioid appearance results from gross and disordered accumulation of cytoplasmic intermediate filaments (10 nm diameter), possibly of desmin type, producing the misleading light microscopical resemblance to epithelioid histiocytes and biphasic pattern of synovial sarcoma. The cause of the filament accumulation is unknown but it may represent a degenerative change leading to necrosis, a characteristic feature of epithelioid sarcoma.

Epithelioid sarcoma. Enzyme histochemical and ultrastructural study

A case of epithelioid sarcoma was studied by electron microscopy and by light and electron microscopic enzyme histochemistry comparing with several control soft tissues. In addition to previously reported ultrastructural features, such as abundant 10 nm cytoplasmic filaments, desmosome-like cell junctions and small cystic spaces surrounded by filopodia or microvilli of the tumor cells, we encountered 10 nm cytoplasmic filaments showing electron dense condensation with a concentrically oriented or whorled pattern and a finger-print-like arrangement and 5'-nucleotidase activity of tumor cell membrane. Among the control soft tissues, 5'-nucleotidase activity was found only in synovial and endothelial cells. Both tumor and synovial cells showed no activity of adenosine triphosphatase, while marked activity of the enzyme was found in endothelial cells. These results support the concept that epithelioid sarcoma is derived from mesenchymal cells undergoing differentiation toward synovial cells during neoplastic transformation.

Monophasic synovial sarcoma, epithelioid sarcoma and chordoid sarcoma: ultrastructural evidence for a common histogenesis, despite light microscopic diversity

Ultrastructural examination of six rare sarcomas--four monophasic spindle cell tumours, one epithelioid sarcoma, one chordoid sarcoma--has revealed marked similarities at the electron microscopic level despite widely divergent light microscopic appearances. These features consisted of: 1 the presence of two cell types, viz. a clear cell and a cell resembling the fibroblast; 2 pseudoglandular spaces with projecting microvilli or filopodia, and with related tight junctions; 3 an amorphous intercellular ground substance with focal condensation into recognizable basement membrane. The findings suggest a common maturation of these diverse tumours to synovial-like tissue, and support the proposal of Hajdu Shiu & Fortner (1977) that these be considered variants of synovial sarcoma. Published ultrastructural studies of synovial, epithelioid and chordoid sarcoma are reviewed in the light of these findings. The ultrastructural differentiation of synovial sarcoma from extraskeletal myxoid chondrosarcoma, chordoma and the spectrum of malignant spindle cell tumours is discussed.

Early distant metastases from epithelioid sarcoma of the hand

The authors describe a patient with epithelioid sarcoma in whom the presenting lesion was cervical lymph node metastasis. This proved to be a difficult diagnostic problem, until the occult primary tumor was discovered in the ipsilateral hand. A cerebral metastasis became evident early in the course of the disease. The authors believe this to be the first case reported in whom the presenting lesion was a nonregional metastasis. The rapid clinical progression of this patient's malignancy is of interest and illustrates the need for early intervention in patients with an epithelioid sarcoma, since the clinical course is not always indolent.

Chordoid sarcoma: ultrastructural evidence supporting a synovial origin

A case of chordoid sarcoma which presented as a painful mass on the dorsum of the right hand in a 72-year-old man was studied by light and electron microscopy. The tumor was composed of lobules separated by thin connective-tissue bands. At the periphery of the lobules, the cells were epithelioid in appearacne and there were numerous nests of clear cells. From the periphery, stellate and spindle shaped cells were radially oriented and formed a loose cobweb arrangement in an abundant loose ground substance. Distinctive ultrastructural features included pseudoacinar formation, microvilli, long cytoplasmic filopodia (often with complex interdigitations), numerous desmosomes, partial basal lamina, scanty endoplasmic reticula, and numerous intracytoplasmic filaments 80--100 A in width. We believe these ultrastructural features indicate a synovial origin of this uncommon neoplasm.

Epithelioid sarcoma and synovial sarcoma in the same knee

A patient who had had a synovial sarcoma removed from the soft tissues adjacent to his knee subsequently developed an epithelioid sarcoma on the opposite side of the same joint. The epithelioid sarcoma metastasized to lymph nodes, invaded blood vessels and produced death 16 years after it was first discovered. The unique association of these two tumors may be an interesting coincidence or may have some relevance to the histogenesis of epithelioid sarcoma.

Epithelioid sarcoma of penis

A rare case of an epithelioid sarcoma of the penis arising as a superficial plaque in the glans and causing pain on erection is reported. This tumor is characterized by a slow growth and infiltrative pattern with a high propensity for local recurrence. Proper treatment is wide local excision.

Epithelioid sarcoma: an analysis of 22 cases indicating the prognostic significance of vascular invasion and regional lymph node metastasis

Twenty-two cases of epithelioid sarcoma seen and/or treated at Memorial Hospital are presented. With the exception of one tumor which occurred in the neck, all the sarcomas arose in the upper (15 cases) or lower extremities (6 cases). Ten originated in the hand. At the time of initial treatment, 14/22 patients were between 20 and 40 years of age. The tumor most commonly presented as a nodular lesion and involved dermis, subcutaneous tissue, fascia and tendons, and when it recurred (13 cases) it tended to grow proximally along tendons and fascial planes. Of special interest was the finding of vascular invasion in surgical specimens removed from 5 patients. Four of these represented recurrent tumor, and in two cases the vascular invasion was massive. Two of these patients also demonstrated tumor emboli in pulmonary vessels and cardiac involvement at autopsy. Metastasis to regional lymph nodes occurred in eight cases (42%). Follow-up ranging from 2 to 34 years (average of 8 years) was obtained for 19 cases (86%). Eleven patients are alive with disease or died as a result of their sarcoma (58% of the follow-up group). Adverse prognostic factors included recurrence after initial local excision, vascular invasion and lymph node metastasis. All of the patients with intravenous extension of tumor and 6 of 8 patients with lymph node involvement died with pulmonary metastases. Our data suggest that cure may best be achieved by amputation or by an exceptionally wide en bloc excision as early as possible, depending upon the location and extent of the original tumor.

Malignant synovioma: electron microscopical findings in three patients and review of the literature

Ultrastructural findings in three malignant synoviomas are described. Two typical "biphasic" tumours contained "epithelial" cells possessing filopodia or microvilli, specialised cell attachment and a basal lamina, and smaller "stromal" cells showing transitions to fibroblasts. In one case, the microvilli included fibrils resembling those in epithelial cells of the intestine and renal tubules. The third tumour was mainly spindle-celled with little epithelial differentiation and no clear division into cell types, but intracytoplasmic microfibrils were conspicuous, forming ovoid masses. The tumour cells differ a good deal from normal human synovial cells but some of the features of the neoplasm are found in inflamed human synovium and in normal synovial membranes of other species. The cytoplasmic fibrils in the third case are similar to those reported by others in epithelioid sarcoma, a tumour that may be of related origin to synovioma; however, the phenomenon may be merely degenerative.