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

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.

SMARCB1/INI1Tumor Suppressor Gene Is Frequently Inactivated in Epithelioid Sarcomas

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

Proximal-type epithelioid sarcoma in a 36-year-old man: closer immunoelectron-microscopic resemblance of the tumor cells to epithelial cells than to mesenchymal cells

Proximal-type epithelioid sarcoma (PES) is a rare neoplasm. We report a case of PES that arose in the perineal subcutis of a 36-year-old Japanese man who died within 4 months of the first clinical sign, probably due to massive pulmonary metastases. In the present study, we analyzed the tumor obtained at surgery, immunohistochemically, immunoelectron-microscopically and genetically. Although the tumor cells in the patient expressed both cytokeratin and vimentin immunohistochemically, they showed epithelial characteristics immunoelectron-microscopically because they had tonofilaments constructed of cytokeratin, not vimentin. In addition, the cytokeratins expressed on the tumor were glandular-type keratins. These findings indicate that PES may be a form of carcinoma in soft tissue. To ascertain the possible origin of the tumor, we compared the tumor immunohistochemically with fetal tissues. Although notochord and fetal peritoneal mesothelium were similar to the tumor antigenically, we could not confirm the specific origin of the tumor. Furthermore, the p53-WAF1 pathway did not contribute to tumorigenesis in the patient because the tumor had no mutation in exons 5-8 of the p53 gene and was immunohistochemically positive for WAF1.

Comparative genomic hybridization in epithelioid sarcoma

BACKGROUND

Epithelioid sarcoma is a rare mesenchymal neoplasm of unknown histogenesis. Data on genome-wide surveys for chromosomal aberrations in epithelioid sarcoma are limited.

OBJECTIVES

To investigate genetic aberrations in epithelioid sarcoma.

METHODS

We analysed seven cases of epithelioid sarcoma (classic type, three cases and proximal type, four cases) by comparative genomic hybridization (CGH), and correlated findings with the results of additional immunohistochemical study.

RESULTS AND CONCLUSIONS

CGH analysis showed DNA copy number changes at one to five different genomic sites in six of seven cases (86%). The majority of the changes were gains. The most frequent gain was at 22q (six cases). Other recurrent changes include gains of 12q24-qter (four cases), 17 (four cases), and 5q32-qter (three cases). High-level homology was seen in chromosomal aberration in both types. In addition, expression of interleukin-2 receptorbeta, located in 22q, was revealed by immunohistochemical method in six cases with gain of 22q, suggesting it may play a role in epithelioid sarcoma tumorigenesis.

Angiosarcoma involving the gastrointestinal tract: a series of primary and metastatic cases

Angiosarcoma occurs very rarely in the intestinal tract as either a primary or metastatic malignancy and can present great diagnostic difficulty, especially when it displays epithelioid cytomorphology. Since only isolated case reports have been published, the purpose of this study is to more fully delineate the histopathological and clinical features from a series of 8 angiosarcomas involving the gastrointestinal tract. There were 5 male and 3 female patients whose ages ranged from 25-85 years (median 57). Presenting symptoms included intestinal bleeding, anemia and pain. Five cases involved the small bowel and 3 involved the colon/rectum. Four cases were primary to the intestinal tract, 2 patients initially presented with secondary involvement of the large bowel from occult retroperitoneal primaries, 1 patient presented with disseminated disease including small bowel involvement, and 1 case was metastatic from a breast primary. Seven cases were composed predominantly of sheets of malignant appearing epithelioid cells with subtle areas forming cleft-like spaces suggestive of vascular differentiation. Immunohistochemical studies revealed the lesional cells to be immunoreactive for CD31 (8/8), CD34 (8/8), Factor VIII (8/8), cytokeratins AE1/AE3 (7/8), cytokeratin 7 (2/8), Cam5.2/cytokeratin 8 (5/8), and cytokeratin 19 (5/8). Cytokeratin 20 was negative in all eight cases, which contrasts sharply with the characteristic positivity for cytokeratin 20 in virtually all intestinal carcinomas. One case was weakly and focally positive for EMA and all cases were negative for S-100 protein. Cytokeratin staining was variable and ranged from focal to extensive. Follow-up was available in eight cases and ranged from 1-33 months (median 12.5). Five patients died of disease, between 1 and 33 months (median 6) after diagnosis. One recently diagnosed patient is alive with disease 18 months after diagnosis, and one patient is free of disease 27 months after original diagnosis. Angiosarcomas of the gastrointestinal tract commonly display epithelioid cytomorphology, may be diffusely and strongly positive for cytokeratins and only show subtle signs of vascular differentiation, creating potential diagnostic confusion with primary or metastatic carcinoma. Given the clinically aggressive behavior of angiosarcoma, proper classification and treatment is important. Immunohistochemistry with vascular markers, CK20, and S-100 protein may be helpful in differentiating angiosarcoma from carcinoma and melanoma.

"Proximal-type" epithelioid sarcoma in a young girl

Epithelioid sarcoma is a rare, malignant soft-tissue neoplasm occurring on the distal extremities of young adults. Its histologic features consist of a proliferation of rounded to plump, spindle-shaped cells with abundant eosinophilic cytoplasm around areas of necrosis, simulating a granulomatous process. Recently a different type of epithelioid sarcoma has been described and named "proximal-type" epithelioid sarcoma. It is found mostly in the pelvic and perineal areas of young to middle-aged adults. On microscopic examination, the tumor is characterized by a proliferation of epithelioid-like cells with rhabdoid features in the absence of a granuloma-like pattern, and immunohistochemically it coexpresses vimentin, cytokeratin, epithelial membrane antigen, and CD34. As we found no report of proximal epithelioid sarcoma in the dermatologic literature, we describe an additional case in a 12-year-old girl. This type of tumor appears to be somewhat more aggressive than the classical, distal type and it should be considered in the differential diagnosis of tumors showing rhabdoid features, in particular extrarenal malignant rhabdoid tumor.

Molecular cytogenetic characterization of proximal-type epithelioid sarcoma

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

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

BACKGROUND

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

CLINICAL CASE

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

CONCLUSION

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

Epithelioid sarcoma of the penis—a rare differential diagnosis of Peyronie's disease

We report on a case of penile epithelioid sarcoma in a 29-year-old man presenting with a dorsal penile plaque that primarily was misdiagnosed as Peyronie's disease. Although the initial clinical findings of these two different entities appear similar, the consequence for the patient is severe. The only way of differentiating these disorders are histological findings. The principal microscopic characteristics of epithelioid sarcoma are the distinctive nodular arrangement, central degeneration and necrosis of the tumor cells with epithelioid appearance and eosinophilia. Immunohistochemical data (cytokeratin, epithelial membrane antigen, vimentin, CD 34, desmin) confirm the diagnosis. We conclude that in cases with slightest doubts on the diagnosis of Peyronie's disease, especially in younger men suffering from a fast-growing penile induration, a bioptic clarification of the entity should be performed to exclude a high malignant disease that can be only treated as far as it is localized by radical surgery.

Recent advances in pediatric renal neoplasia

Over the past 6 years, molecular genetic studies have significantly advanced our understanding of pediatric renal neoplasms. The cellular variant of congenital mesoblastic nephroma (but not the classic variant) has been shown to bear the same t(12;15)(p13;q25) and ETV6-NTRK3 gene fusion as infantile fibrosarcoma, a tumor with which it shares morphologic and clinical features. Rhabdoid tumor of the kidney is characterized by deletion of the hSNF5/INI1 gene, which links it to other rhabdoid tumors of infancy that arise in the soft tissue and brain. Primary renal synovial sarcomas and renal primitive neuroectodermal tumors have become accepted entities, and likely comprise a subset of what had previously been termed "adult Wilms tumor." Renal carcinomas associated with Xp11.2 translocations that result in fusions involving the TFE3 transcription factor gene have been delineated, including a distinctive neoplasm that shares the identical gene fusion as alveolar soft part sarcoma. Most recently, a distinctive type of renal neoplasm with a t(6;11)(p21;q12) has been described, and the cloning of the resulting gene fusion links it to the Xp11 translocation carcinomas. Together, these last two translocation-associated tumors represent a significant proportion of pediatric renal cell carcinomas. This review highlights each of these recent advances.

Myoepithelial tumors of soft tissue: a clinicopathologic and immunohistochemical study of 101 cases with evaluation of prognostic parameters

Myoepitheliomas and mixed tumors were only recently recognized to occur primarily in soft tissue, and only small case numbers have been described. To characterize these tumors further and to evaluate prognostic parameters, 101 myoepithelial tumors of soft tissue were retrieved from the authors' consult files. Hematoxylin and eosin sections were reexamined, immunohistochemistry was performed, and clinical details were obtained from referring physicians. Fifty-three patients were male and 48 female (mean age 38 years; range 3-83 years). Tumor size ranged from 0.7 to 20 cm (mean 4.7 cm). Most tumors arose in the extremities and limb girdles: 41 in the lower limbs, 35 in the upper limbs, 15 in the head and neck, and 10 in the trunk. Fifty-four tumors were situated in subcutis and 37 in deep soft tissue (depth unstated in 10). Most cases were grossly well circumscribed; 43 showed microscopically infiltrative margins. Histologically, most tumors were lobulated, composed of cords or nests of epithelioid, ovoid, or spindled cells with a variably reticular architecture and a chondromyxoid or collagenous/hyalinized stroma. Eight cases showed a predominantly solid proliferation of spindled or plasmacytoid cells; 17 demonstrated ductular differentiation (mixed tumors). Cartilage was present in 6 cases, 6 contained bone, and 4 others contained both. Mitoses ranged from 0 to 68 per 10 high power fields (mean 4.7 per 10 high power fields). Tumors with benign cytomorphology or mild cytologic atypia (low-grade) were classified as myoepithelioma or mixed tumor, whereas tumors with moderate to severe atypia (high-grade) were classified as myoepithelial carcinoma (epithelioid or spindled cells with vesicular or coarse chromatin, prominent, often large nucleoli, or nuclear pleomorphism) or malignant mixed tumor (cytologically malignant cartilage or bone). Sixty-one cases were myoepitheliomas or mixed tumors, and 40 were myoepithelial carcinomas or malignant mixed tumors. By immunohistochemistry, all cases with available material were reactive for epithelial markers (keratins and/or epithelial membrane antigen): 90 of 97 (93%) expressed keratins (most often AE1/AE3 or PAN-K), 84 of 97 (87%) S-100 protein, 44 of 51 (86%) calponin, 52 of 83 (63%) epithelial membrane antigen, 40 of 87 (46%) glial fibrillary acidic protein, 27 of 75 (36%) smooth muscle actin, 15 of 66 (23%) p63, and 7 of 51 (14%) desmin. Follow-up was available for 64 patients. Among 33 cases with benign or low-grade cytology (mean follow-up 36 months; range 4-168 months), 6 recurred locally (18%) and none metastasized. No clinical or histologic features correlated with recurrence. Among 31 cytologically malignant cases (mean follow-up 50 months; range 4-252 months), 13 recurred locally (42%) and 10 metastasized (32%); so far, 4 patients have died of metastatic tumor. This study expands the spectrum of myoepithelial tumors of soft tissue to include myoepithelial carcinomas and malignant mixed tumors, which pursue an aggressive clinical course. Although the majority of morphologically benign or low-grade myoepithelial neoplasms of soft tissue behave in a benign fashion, there is an approximate 20% risk for local recurrence.

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.

Identification of poorly differentiated synovial sarcoma: a comparison of clinicopathological and cytogenetic features with those of typical synovial sarcoma

AIMS

Poorly differentiated areas in synovial sarcomas (SS) are known to be associated with a poorer prognosis. The aim of our study was to describe the morphological spectrum of poorly differentiated synovial sarcomas (PDSS) and refine the criteria for their recognition.

METHODS AND RESULTS

The clinicopathological features of 28 PDSS were compared with those of 26 classic SS. Common cell types in PDSS included epithelioid, spindle and Ewing sarcoma-like small round cells. Unusual features included presence of desmoplastic small cell tumour-like areas and extraskeletal myxoid chondrosarcoma-like areas. The presence of necrosis (P = 0.002), a mitotic rate over 10/10 high-power fields (P < 0.001), a haemangiopericytomatous vascular pattern (P < 0.001) and vascular invasion (P = 0.003) were significantly associated with PDSS, while mast cells (P < 0.001), calcification (P < 0.001) and hyaline bands (P < 0.001) were significantly associated with classic SS. Poorly differentiated areas showed increased proliferative activity with Ki67. PDSS showed a tendency to be larger (P = 0.008) and to be located in proximal more than distal sites (P = 0.025). Three entirely poorly differentiated tumours were diagnosed by demonstration of the t(X;18)(p11;q11) translocation. PDSS showed additional cytogenetic abnormalities.

CONCLUSIONS

Poorly differentiated synovial sarcomas show a spectrum of histological features, which may simulate other malignant neoplasms. The diagnosis of entirely poorly differentiated synovial sarcomas requires cytogenetic analysis.

CD31 staining in epithelioid sarcoma

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

Epithelioid sarcoma of the uterine cervix

BACKGROUND

Epithelioid sarcoma is a rare, yet aggressive soft tissue neoplasm that has not previously been reported to originate in the cervix.

CASE

A 29-year-old woman was seen in consultation at our institution after having been diagnosed with a poorly differentiated carcinoma of the cervix, which was treated with radiation and chemotherapy. Examination of the original biopsy material with additional studies led to a diagnosis of epithelioid sarcoma of the cervix.

CONCLUSION

Epithelioid sarcoma can occur in the cervix and should be included in the differential diagnosis of cervical neoplasms. Additional cases are needed to develop optimum treatment strategies and predict prognosis.

Neuroendocrine carcinomas of the pancreas with 'Rhabdoid' features

Neuroendocrine carcinomas of the pancreas are rare neoplasms whose morphologic features generally mirror those seen in neuroendocrine tumors in other organs. Rarely, however, they may display unusual morphologic appearances that can introduce difficulties for diagnosis. We report four cases of primary neuroendocrine carcinomas of the pancreas (islet cell tumors) that were characterized by prominent "rhabdoid" features of the tumor cells. The lesions occurred in two men and two women 37-79 years of age who presented with symptoms of biliary obstruction and epigastric pain; one patient had recurrent gastric ulcers and an elevated gastrin level. The tumors were located in the head and tail of the pancreas and measured 2.5-4.5 cm in greatest diameter. Histologic examination revealed sheets of monotonous tumor cells with uniform round nuclei showing dispersed chromatin and containing abundant densely eosinophilic cytoplasmic inclusions that displaced the nuclei toward the periphery. In all cases, the rhabdoid elements appeared to merge with areas showing a more conventional neuroendocrine morphology. Immunohistochemical studies in all cases showed strong cytoplasmic positivity of the rhabdoid tumor cells for chromogranin, synaptophysin, and cytokeratin. Recognition of this unusual morphologic appearance is of importance to avoid mistaking these lesions for other types of malignant neoplasm.

Renal cell carcinoma with rhabdoid features: an aggressive neoplasm

AIMS

Only a few reports on renal cell carcinoma with rhabdoid features have been published. This study was performed to investigate the clinicopathological characteristics of renal cell carcinomas with rhabdoid features.

METHODS AND RESULTS

Among 253 cases of renal cell carcinoma in adults, eight cases with rhabdoid features were detected. Rhabdoid areas ranged from 10% to 90% of each of the cases. Seven of the eight cases were TNM stage III or IV, and four of the eight cases died within 8 months of surgery. Immunohistochemically, the rhabdoid areas were positive for CAM 5.2 (4/8), AE1/AE3 (6/8), epithelial membrane antigen (6/8) and vimentin (8/8), and negative for myogenetic markers (0/8). The mean MIB-1 labelling index in the rhabdoid areas was higher than that in the definite carcinomatous areas. Ultrastructurally, perinuclear whorls of intermediate filaments were demonstrated in three of the eight cases using paraffin-embedded blocks.

CONCLUSIONS

The rhabdoid areas in renal cell carcinoma have histological, immunohistochemical and ultrastructural similarities to malignant rhabdoid tumours. Renal cell carcinoma with rhabdoid features is a highly aggressive neoplasm and its malignant behaviour may be due to the high cell-proliferative activity of the rhabdoid areas. Rhabdoid features in renal cell carcinoma may represent the endpoint of clonal evolution of renal cell carcinoma (especially in clear cell type cases).

Radiologic manifestations of proximal-type epithelioid sarcoma of the soft tissues

OBJECTIVE

Our study was conducted to summarize the clinical and radiologic presentations and imaging features of proximal-type epithelioid sarcoma, a rare aggressive soft-tissue sarcoma, in 16 patients.

CONCLUSION

The chest wall, inguinal region, thigh, and perineum were the most common sites of the disease. Tumors exhibited multilobulated contours in 87.5% of the patients, which may be suggestive of this tumor type. Nodal involvement was identified on CT and MR imaging and confirmed pathologically in 62.5% of the patients. Although CT or MR findings are nonspecific, proximal-type epithelioid sarcoma shows a multinodular configuration and admixes with regional lymph node metastasis on imaging studies.

Angiosarcoma arising in hemangioma/vascular malformation: report of four cases and review of the literature

Malignant change in a benign vascular tumor is exceedingly rare, and there have been only five previously reported convincing cases. Four new cases of angiosarcoma (AS) arising in a hemangioma/vascular malformation (HVM) are described. All patients were in the 6th or 7th decade of life (two female, two male). Development of an enlarging deep-seated mass was the main presenting symptom. MRI disclosed the presence of two separate soft tissue masses in both thighs in one patient. No patient had a history of prior radiotherapy at the same site. Preoperative duration, known in three cases, ranged from 1 to 24 months (median 12 months). Three tumors were located in the lower extremities (thigh and buttock), one in the retroperitoneum, and one in the parotid region. Three patients were treated by marginal excision; in one case only a biopsy was performed. Radiotherapy/chemotherapy was given in all cases. Two patients were disease free 2 and 14 months after surgery and two developed metastases. Grossly, the tumors were described as frankly hemorrhagic masses or as firm, whitish areas with hemorrhagic nodules and were centered in skeletal muscle in three cases. Size ranged between 2.2 cm and 8 cm (median 4.3 cm). Histologically, all the tumors had two distinct components. In three cases the benign and the malignant components were variably intermixed, whereas in one case the HVM was mainly located at the edge of the malignant tumor. The benign component showed features of an arteriovenous hemangioma (three cases) or intramuscular capillary hemangioma. AS showed epithelioid morphology in three cases and a well-differentiated dissecting pattern in one case. An imperceptible transition between the two components was noted in two cases. The two anatomically separate masses excised from one patient appeared almost identical. All cases were positive for at least two endothelial markers (CD31, CD34, VWF) and negative for the epithelial markers (EMA, AE1/AE3, Pan-keratin). Possible mechanisms for this exceptional phenomenon are discussed.

Cytologic features of alveolar soft part sarcoma: report of three cases

Alveolar soft part sarcoma (ASPS) is a rare, high-grade, epithelial-like sarcoma that shows characteristic histopathologic findings. Although a chromosomal anomaly that seems specific has been recently described, its diagnosis is based on histologic and ultrastructural features. The tumor shows no specific immunohistologic findings. Cytologic features of three cases of ASPS are presented. Preoperative fine-needle aspiration (FNA) of the primary soft tissue tumor was performed in two cases. In another two, mediastinal and pulmonary and subcutaneous metastatic lesions were aspirated. In all cases the cytologic image was identical with numerous, dissociated, large neoplastic cells with round-to-plasmocytoid morphology. Cytoplasmic fragility and granularity with abundant, atypical, naked nuclei were present. In one case, FNA material was available for ultrastructural studies. It disclosed the characteristic cytoplasmic crystalline structures. A specific cytologic diagnosis of ASPS was given in all cases. In conclusion, ASPS is a rare neoplastic entity that shows a characteristic cytologic image. When accompanied by an adequate clinical context it permits specific preoperative recognition. While immunocytologic studies are helpful to exclude other neoplasms, ultrastructure may result in an exact diagnosis.

Rhabdoid epithelioid leiomyosarcoma of the uterine corpus: a case report and literature review

A case of epithelioid leiomyosarcoma of the uterus with rhabdoid phenotype and early rhabdomyoblastic differentiation is described. A 72-year-old woman with a 5-week history of increased abdominal girth was found to have a large pelvic mass. The uterus revealed a large intramyometrial and left adnexal necrotic tumor that had spread to the small bowel mesentery and to the anterior abdominal peritoneum. The tumor was an epithelioid leiomyosarcoma with rhabdoid phenotype and focal early rhabdomyoblastic differentiation, as confirmed by immunohistochemical and ultrastructural techniques. Also called composite extrarenal rhabdoid tumor (CERT), this lesion should be differentiated from malignant mixed müllerian tumor, rhabdomyosarcoma, endometrial stromal sarcoma, and pure rhabdoid tumors of the uterus. The recognition of a rhabdoid phenotype is of clinical importance since these tumors are prone to be aggressive.

Lipoblastoma-like tumour of the vulva: report of three cases of a distinctive mesenchymal neoplasm of adipocytic differentiation

AIMS

We sought to delineate and describe three cases of a distinctive mesenchymal neoplasm of the vulva showing adipocytic differentiation and affecting young patients.

METHODS AND RESULTS

In three patients between 13 and 38 years of age, the vulvar tumours had well-circumscribed borders and ranged in size from 35 to 100 mm. Histologically, they were well circumscribed and lobulated. The lobules were separated by thin fibroconnective tissue septa and were composed of slender spindle cells showing slightly eosinophilic cytoplasm with indistinct boundaries, uniform nuclei with finely granular chromatin, and no nucleoli. The cells were embedded in a richly myxoid stroma. The background in all three tumours was a 'chicken-wire', capillary vascular network resembling that seen in myxoid liposarcomas. Two tumours had scattered signet-ring-type lipoblasts and the third a large number of such lipoblasts. Clusters of mature adipocytes were entrapped in the tumours. None had mitotic figures, necrosis, or pleomorphism. The neoplastic cells stained positively for vimentin and were negative for other immunohistochemical markers. Treatment for all three tumours was enucleation alone. After follow-up of 10 years, 7 years, and 1 year, all patients are well with no evidence of disease.

CONCLUSIONS

The benign behaviour of these neoplasms militates against the diagnosis of liposarcoma. We believe these are benign lesions of adipocytic differentiation akin to infantile lipoblastomas.

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.

Primary epithelioid sarcoma of the dura: case report

OBJECTIVE AND IMPORTANCE

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

CLINICAL PRESENTATION

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

INTERVENTION

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

CONCLUSION

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

Epithelioid sarcoma: results of conservative surgery and radiotherapy

PURPOSE

To determine the outcome and prognostic factors for patients with localized epithelioid sarcoma treated with conservative surgery and radiotherapy (RT).

METHODS AND MATERIALS

The medical records of 24 patients with nonmetastatic epithelioid sarcoma treated with conservative surgery and RT were reviewed. Preoperative RT was given to 3 patients (median 46.4 Gy) and postoperative RT to 21 patients (median 64.5 Gy). A local (limb-sparing) surgical procedure was performed in all patients.

RESULTS

At a median follow-up of 131 months, 14 patients had relapsed and 13 patients had died. The actuarial overall and disease-free survival rate at 10 years was 50% and 37%, respectively. Local, nodal, and metastatic failure occurred in 7, 4, and 10 patients, respectively, yielding a 10-year actuarial local, nodal, and metastatic control rate of 63%, 81%, and 56%, respectively. Univariate analysis revealed that size < or =5 cm and extremity location were favorable prognostic factors for overall, disease-free, and metastasis-free survival. The actuarial 5-year overall, disease-free, and metastasis-free survival rate was 79% vs. 25% (p = 0.002), 51% vs. 13% (p = 0.03), and 79% vs. 13% (p <0.001), respectively, for lesion size < or =5 vs. > 5 cm. The actuarial 5-year overall, disease-free, and metastasis-free survival rate was 77% vs. 39% (p = 0.002), 56% vs. 0% (p = 0.01), and 78% vs. 17% (p = 0.01), respectively, for extremity vs. nonextremity location. Multivariate analysis of the factors correlating with the overall, disease-free, and metastasis-free survival confirmed the favorable prognostic significance of small lesion size. The prognostic significance of extremity location on univariate analysis was explained by an imbalance in the mean tumor sizes.

CONCLUSIONS

Epithelioid sarcoma is an aggressive soft-tissue sarcoma, with high rates of local and distant relapse. Local control with conservative surgery and RT compares favorably to published surgical series. The poor outcome for tumors > or =5 cm in size emphasizes the need for effective systemic therapy.

Fine-needle aspiration of epithelioid sarcoma: cytology findings in nine cases

BACKGROUND

Epithelioid sarcoma is a rare tumor with characteristic morphologic and immunohistochemical features. It can be confused histologically and cytologically with a variety of benign and malignant lesions, including a granulomatous process, synovial sarcoma, melanoma, squamous cell carcinoma, and adenocarcinoma. The objective of this study was to define the cytologic features of this rare tumor.

METHODS

The cytologic features of nine histologically confirmed epithelioid sarcomas were analyzed. The criteria evaluated included cell size and shape, cell borders, cluster organization, cytoplasmic characteristics, nuclear and nucleolar features, and background characteristics.

RESULTS

In most cases, single, dispersed cells represented the predominant pattern, with only a few small clusters present. The cells were mostly round with interspersed spindle cells and mild to moderate pleomorphism. The nuclei were large and eccentrically located, with a plasmacytoid appearance. A pale zone in the perinuclear area was evident in three of nine cases. Well-defined cell borders with intercellular spaces between malignant cells were observed in eight cases. In three cases, a granuloma-like structure was identified. In two cases, the cells were mostly spindle and showed greater cellular pleomorphism.

CONCLUSION

Epithelioid sarcoma is an uncommon tumor with a wide range of differential diagnoses, especially in cytology specimens. Awareness of its existence and knowledge of its cytologic features are important for a correct diagnosis.

Fine-needle aspiration cytology of "proximal-type" epithelioid sarcoma

The cytologic and immunocytologic findings in a case of recurrent "proximal-type" epithelioid sarcoma (ES) of the vulva are presented. This is a recently described neoplasm that differs clinically and morphologically from conventional ES. Cytologic smears showed a dissociated population of large, atypical neoplastic cells with bi- and multinucleated cells, abundant cytoplasm, and rhabdoid-like morphology. Due to its different clinical management it must be differentiated from metastatic carcinoma and melanoma. From a practical perspective, its differentiation from other epithelial-like sarcomas is less important. In conclusion the cytopathologic findings of "proximal-type" ES show a good correlation with histopathology, permitting the diagnosis of recurrences and metastases. When accompanied by adequate clinical information and ancillary studies, a specific preoperative recognition seems possible.

Expression of Fli-1, a nuclear transcription factor, distinguishes vascular neoplasms from potential mimics

Fli-1 protein, a member of the ETS family of DNAbinding transcription factors, is involved in cellular proliferation and tumorigenesis. Approximately 90% of Ewing's sarcoma/primitive neuroectodermal tumors (ES/PNET) have a specific translocation, t(11;22)(q24;q12), which results in fusion of EWS to Fli-1, and production of an EWS-Fli-1 fusion protein. We have recently shown that immunohistochemistry for the carboxy terminal of Fli-1 protein is sensitive and highly specific for the diagnosis of ES/PNET. In our earlier study we noted that among normal tissues only endothelial cells and small lymphocytes expressed Fli-1. Fli-1 expression in vascular neoplasms has not been previously studied. Formalin-fixed paraffin-embedded tissue from 54 vascular tumors and 75 nonvascular tumors were immunostained for Fli-1 (1:120, Sc 356, Santa Cruz Biotechnology, Santa Cruz, CA), after steam heat-induced epitope retrieval. Only cases with >10% of cells showing nuclear staining were accepted as positive. Cases without positive internal controls (endothelium and small lymphocytes) were not scored. Positive internal controls were present in 122 of 129 cases (95%). One vascular tumor (Kaposi's sarcoma) and 7 nonvascular tumors (2 epithelioid sarcomas and 5 carcinomas) without internal controls were not scored. Fli-1 was expressed by 50 of 53 vascular tumors scored (94%), including 20 of 22 angiosarcomas, 11 of 12 hemangioendotheliomas, 7 of 7 hemangiomas, and 12 of 12 Kaposi's sarcomas. In contrast, Fli-1 expression was absent in the 68 nonvascular tumors scored (0 of 68), including 16 sarcomas, 7 melanomas, and 45 carcinomas. The results of this study strongly suggest a role for Fli-1 as a novel marker of both benign and malignant vascular tumors. The sensitivity (94%) and specificity (100%) of Fli-1 with regards to the cases evaluated in this study equal or exceed those of the established vascular markers, CD31, CD34, and von Willebrand factor. As the first nuclear, rather than cytoplasmic or membranous marker of endothelium, Fli-1 immunostaining also generally lacks cytoplasmic staining artifacts that are the result of endogenous peroxidases or biotin.

Primary epithelioid sarcoma of the vulva

A case of a 31-year-old woman with epithelioid sarcoma of the vulva which metastasized to the regional lymph node 8 years after onset of the disease is reported here. The patient first noticed a painless subcutaneous mass of 5 mm in diameter in the right labium majus at age of 21. This was excised locally at age 23, but recurred 17 months later. Although local excision was again performed, the tumor recurred and continued to enlarge very slowly. At this stage, based on the pathology of both the initial and second tumors, the diagnosis was of a benign inflammatory process. However, local recurrence and inguinal lymph node swelling occurred at age 29, and biopsy was taken. The pathology report indicated benign granulomatous changes. The slides were reconsidered and re-interpreted as epithelioid sarcoma, whereupon radical vulvectomy was performed at age 31. Vulvar epithelioid sarcoma with inguinal lymph node metastasis was first diagnosed at that time. Epithelioid sarcoma of the vulva is an exceedingly rare tumor, and only 15 cases have been reported thus far in the literature. Early diagnosis and curative treatment of this tumor may be problematic for gynecologists because of its rarity and therefore little-known characteristic clinical behavior and histology. Radical vulvectomy or extensive local excision with inguinal lymphadenectomy at the time of diagnosis is recommended as the treatment of choice.

Rhabdoid papillary meningioma

We have studied an uncommon case of rhabdoid papillary meningioma in a 15-year-old boy with a dura-based mass arising in the left posterior fossa. The patient exhibited prominent extracranial extension during the past 6 years, consisting of a mixture of both perivascular pseudopapillary growth and rhabdoid cytologic features of neoplastic meningothelial cells. The meningothelial features were evidenced by the focal whorl formation of tumor cells, coexpression of epithelial membrane antigen and vimentin, and ultrastructural findings of interdigitated cytoplasmic process and intercellular junction. However, the regional and histologic resemblances to ependymoma were further complicated by unexpected focal expression of glial fibrillary acidic protein, neurofilament, and alpha-smooth muscle actin of the tumor cells. The rhabdoid morphology was characterized by sheets of tumor cells with eccentric nuclei and abundant eosinophilic cytoplasm with often recognizable intracytoplasmic hyaline inclusions. These inclusions revealed ultrastructural paranuclear whorls of intermediate filaments, ruling out the other forms of intracytoplasmic eosinophilic inclusions resembling rhabdoid morphology. Diagnosis of an unusual rhabdoid papillary meningioma with aggressive behavior is resoluble by immunohistochemical and ultrastructural analyses.

Proximal-type epithelioid sarcoma: a clinicopathologic study of 20 cases

We studied the clinicopathologic and immunohistochemical features of 20 cases of proximal-type epithelioid sarcoma to identify prognostic factors. The 20 patients ranged in age from 13 to 80 years (mean, 40 y); 12 patients were male and 8 were female. The tumors presented as deep soft-tissue or subcutaneous masses on the inguinal region in five, the thigh in four, the vulva in three, the axilla in three, and one each in the flank, chest wall, back, hip and perineum. The tumors ranged from 2 to 16 cm at their greatest diameter (mean: 7.8 cm). Histologically, 12 tumors (60%) were classified as the large-cell subtype, characterized by sheets of large cells with prominent nucleoli resembling poorly differentiated carcinoma, and a frequent rhabdoid phenotype, six (30%) were classified as the conventional subtype, and two (10%) as the angiomatoid subtype. The numbers of tumors exhibiting immunoreactivity for various markers were: vimentin (20 cytokeratin (20 [100%]); epithelial membrane antigen (17 [85%]); CD34 (9 [45%]); CD99 (5 [25%]); muscle markers, either desmin or alpha-smooth muscle actin (3 [15%]), other markers such as S-100 protein, neurofilament, neuron-specific enolase, synaptophysin and CD56 (12 [60%]); and p53 (16 [80%]). Fourteen lesions (70%) exhibited an MIB-1 index of 30% or more and, by a system of histologic grading using the MIB-1 score, 16 tumors (80%) were classified as high-grade (Grade 3). Thirteen patients (65%) developed local recurrence and 15 (75%) had metastases, primarily to the lymph nodes. At the last follow-up, 13 patients (65%) had died of their disease. A large tumor size and early metastasis were independently associated with a poor outcome. We conclude that proximal-type epithelioid sarcomas are rare, undifferentiated soft-tissue sarcomas of adults, with epithelioid features and a frequent rhabdoid phenotype. These tumors, when arising in proximal locations, have a much worse prognosis than those arising in distal locations.

Expression of intercellular adhesion molecules in epithelioid sarcoma and malignant rhabdoid tumor

We clinicopathologically evaluated 31 cases of epithelioid sarcoma (ES; 25 'classical' type and six 'proximal variant' type) and six cases of malignant rhabdoid tumor (MRT; three extrarenal and three renal). We also did immunohistochemical studies on 12 classical and three proximal variant cases of ES, and six cases of MRT, to clarify the differences in biological behavior in these tumors. E-cadherin, beta-catenin and CD34 expression was evaluated. We also carried out mutational analysis of exon 3 of the beta-catenin gene by polymerase chain reaction-single-strand conformation polymorphism analysis. In ES, the 5- and 10-year survival rates were 71.1 and 55.3%, respectively. A high mitotic rate (>15/10 high-power fields) was significantly correlated with a poor overall survival rate in ES (P = 0.0248). E-cadherin expression was observed in nine cases (69.2%) of ES and in four cases (66.7%) of MRT. Most of these tumors showed aberrant E-cadherin expression. Seven cases (46.7%) of ES were positive for CD34, although none of the cases of MRT were CD34 positive. Eleven cases (73.3%) of ES were positive for beta-catenin, which was localized to the cellular membrane, whereas all of the cases of MRT were beta-catenin negative. Mutational analysis for the beta-catenin gene was done in nine cases of ES and six cases of MRT, however, genetic alteration was not found. From our results, we conclude that beta-catenin membranous expression could be a useful marker for distinguishing ES, including the proximal variant, from MRT.

Pleomorphic liposarcoma of a young woman following radiotherapy for epithelioid sarcoma

A case of a metachronous epithelioid sarcoma and pleomorphic liposarcoma in a young woman is described. The first tumor was an epithelioid sarcoma (ES) with focal rhabdoid features localised in the left calf while the second lesion developed seven years later in the same region was diagnosed as pleomorphic liposarcoma resembling myxofibrosarcoma ( myxoid variant of malignant fibrous histiocytoma ) predominantly composed of moderately differentiated spindle cells. Multiple foci of uni- and plurivacuolated lipoblasts were seen. Following the resection of ES the patient received 57 Gy radiation to the region, therefore we regarded the second tumor as a radiation induced liposarcoma. A further interesting feature of this case is that the development of pleomorphic liposarcoma preceded by 6 months the solitary right parabronchial metastasis of ES and after 4 months of metastasectomy a third tumor developed at the site of the first lesion. This tumor showed dedifferentiation toward pleomorphic malignant fibrous histiocytoma. Our case represents a unique case of postirradiation liposarcoma developed on the base of ES.

h-Caldesmon expression effectively distinguishes endometrial stromal tumors from uterine smooth muscle tumors

Distinction of endometrial stromal neoplasms from cellular smooth muscle tumors of the uterus is sometimes difficult. Immunohistochemistry is often not helpful because muscle actins and desmin are expressed in both neoplasms. This study's goal was to determine whether h-caldesmon, a smooth muscle-specific isoform of a calcium, calmodulin, and actin binding protein, could effectively distinguish endometrial stromal tumors from uterine smooth muscle tumors. The authors analyzed immunohistochemical expression in 24 endometrial stromal neoplasms (21 sarcomas and three nodules), 29 leiomyosarcomas, 32 leiomyomas (10 "usual," 14 cellular leiomyoma, and eight "highly cellular" types), 40 myometria, and 25 endometria. h-Caldesmon was diffusely positive in all myometria, leiomyomata, and leiomyosarcomas. Of note, 16 leiomyosarcomas (55%) were positive for h-caldesmon in more than 50% of tumor cells. In five "highly cellular" leiomyomas, h-caldesmon expression was markedly decreased or absent in areas morphologically resembling endometrial stromal tumors, raising the possibility that these tumors may be mixed smooth muscle-endometrial stromal neoplasms. In contrast, h-caldesmon expression was absent in all endometria and endometrial stromal neoplasms apart from accompanying small vessels. Desmin was diffusely positive in all myometria and leiomyomata. The fraction of cells expressing desmin was greater than that of h-caldesmon in only 10% of leiomyosarcomas. Focal desmin expression was also present in eight of 25 (32%) endometria and 12 of 24 (50%) endometrial stromal neoplasms. h-Caldesmon appears to be a more sensitive and specific marker of smooth muscle differentiation in the uterus than desmin and may be a useful tool for distinguishing and classifying uterine mesenchymal tumors.

Mesenchymal tumors and tumor-like lesions of the female genital tract: a selective review with emphasis on recently described entities

The diverse mesenchymal tumors and tumor-like lesions that occur within the female genital tract include a number of lesions that have only been recently characterized and others about which there is new information. In this group are the aggressive angiomyxoma, angiomyofibroblastoma, and cellular angiofibroma. Criteria for the distinction of these lesions are reviewed, as are the pathologic features of prognostic significance in assessing smooth muscle tumors of the vulva. The diagnostic problems that the epithelioid variant of smooth muscle tumors, both benign and malignant, may pose when they occur in various areas of the genital tract are discussed, particularly with regard to problems encountered in the ovary, a site where the diagnosis often is not considered. Recent information expanding the morphologic spectrum of fibroepithelial polyps of the genital tract is presented, and important non-neoplastic entities, including nodular fasciitis and the postoperative spindle cell nodule, are reviewed. Mesenchymal tumors of the various types seen in the soft tissues may be encountered anywhere in the female genital tract and have been the subject of particular recent interest in the ovary; issues relevant to differential diagnosis are reviewed.

Poorly differentiated follicular thyroid carcinoma with rhabdoid phenotype: a clinicopathologic, immunohistochemical and electron microscopic study of two cases

Poorly differentiated thyroid carcinomas with follicular cell phenotype are not well defined. Different diagnostic criteria have been employed for these tumors, including solid growth, nodular, trabecular, and insular patterns. Cytologic features, such as a predominance of tall and columnar cells, have been considered to be diagnostic of poorly differentiated carcinoma. However, there is no agreement among surgical pathologists regarding morphologic criteria for poorly differentiated thyroid carcinoma. We report two unique thyroid neoplasms that we interpreted as poorly differentiated follicular carcinomas. Nodular, trabecular, and sheetlike patterns predominated in both tumors. They were composed of cells that were focally immunoreactive for thyroglobulin and had large vesicular nuclei with prominent nucleoli. A variable number of cells showed rhabdoid phenotype. The rhabdoid inclusions did not stain for thyroglobulin but contained whorls of intermediate filaments that were vimentin positive. There were foci of necrosis and numerous mitotic figures. Both patients were adults and died with multiple pulmonary metastases. The presence of rhabdoid cells in poorly differentiated follicular carcinomas broadens the spectrum of tumors with rhabdoid phenotype. More cases are needed to determine whether the rhabdoid phenotype is a marker for poorly differentiated follicular carcinoma as well as an independent adverse prognostic factor.

Cytokeratin subunits of inclusion bodies in rhabdoid cells: immunohistochemical and clinicopathological study of malignant rhabdoid tumor and epithelioid sarcoma

Extrarenal malignant rhabdoid tumor (MRT), which is recognized as being histologically similar to renal MRT, is characterized by the presence of "rhabdoid cell" (RC) and a highly aggressive biological behavior. Recently it has been proposed that "proximal variant" of epithelioid sarcoma (ES), whose morphology is similar to that of MRT, actually has a more aggressive clinical course than classical type ES. Detailed immunohistochemical analysis of cytokeratin (CK) subunits was performed in 3 cases of extrarenal MRT, 3 cases of renal MRT, and 11 cases of ES comprising 2 "proximal variants" and 9 classical types. Renal and extrarenal MRTs showed positive immunoreactivity for both CK8 and CK18. Classical type ESs were diffusely positive, not only for CK8 and CK18, but also for other cytokeratin subunits including CK4, 6, 10, 13, 16, 17, and "high-molecular-weight" CKs (CK1, 5, 10, and 14). On the other hand, proximal ES revealed limited immunohistochemical reactivity for cytokeratins, compared with classical ES. In conclusion, the inclusion bodies of RCs show immunoreactivity confined to CK8, CK18, and vimentin. Furthermore, ES has additional CK expressions, while proximal ES possesses characteristics intermediate between those of classical ES and those of external MRT.

Malignant rhabdoid tumor of the vulva: case report and review of the literature with emphasis on clinical management and outcome

BACKGROUND

Malignant extrarenal rhabdoid tumors (ERTs) of the vulva are rare but aggressive neoplasms. We describe the eighth reported case and the first to have long-term survival despite initial rapid recurrence.

CASE

A 40-year-old woman presented with a painless lump on the mons pubis. It was excised and revealed an ERT. One month later, the tumor had regrown. A wide local excision and superficial right groin node dissection was performed. Local recurrence was noted 11 months after the initial excision and was treated by wide excision and radiotherapy. She is without evidence of disease 61 months after initial presentation.

CONCLUSION

A review of previously reported cases of ERT reveals that the median survival is 9 months. Local recurrences are common and the appearance of distant metastases is almost invariably rapidly fatal. Chemotherapy and radiotherapy do not appear to be effective in controlling disease. Initial surgical extirpation may offer the best chance of cure.

Common chromosome aberrations in the proximal type of epithelioid sarcoma

A new case of the proximal type of epithelioid sarcoma with a complex karyotype 70-98 <4N>,XX,-X,-X,+5,i(5)(q10),+7,del(7)(q31),i(8)(q10)x3 approximately 4,del(12)(p13),der(18)ins(18:?) (q11;?)del(18)(p11). ish der(18)ins(18;X)del(18)(p11)(wcp18+,wcpX+),+20,+20,dmin [cp9] is described. Both, dual-color FISH using probes specific for OATLI1/OATL2 genes and RT-PCR analysis excluded the presence of t(X;18), typical for synovial sarcoma. Our case together with the previously published ones suggest that the presence of i(8)(q10), losses of 12p and 18p together with the gain of chromosome 20 may represent a common cytogenetic aberrations in the proximal type of epithelioid sarcoma.

Rhabdoid features in leiomyosarcoma of soft tissue: with special reference to aggressive behavior

The presence of rhabdoid cells has been reported in various types of malignant neoplasms and has been determined to be a predictor of aggressive behavior of neoplasms regardless of tumor histogenesis. One hundred and thirteen cases of leiomyosarcoma, selected from 1800 soft tissue sarcomas, were reviewed on hematoxylin and eosin sections, and immunohistochemical staining when available, and seven cases with rhabdoid features were retrieved. Clinicopathologic differences were analyzed to compare between cases with rhabdoid features and those without rhabdoid features. In the seven cases with rhabdoid features, two were intra-abdominal, and the others arose in external soft tissues including muscle, subcutis, and cutis. Patient age ranged from 33 to 84 years, three were female, and four were male. Tumor size ranged from 3 to 22 cm. Clinical evidence showed no differences from those cases without rhabdoid features. Histologically, one of the abdominal cases was epithelioid leiomyosarcoma. Two of the 7 cases were better subclassified as pleomorphic leiomyosarcoma, in which rhabdoid cells are diffusely scattered. In cases other than those with pleomorphic leiomyosarcomas, foci of anaplastic areas were observed, and collections of rhabdoid cells were present in those areas. Immunohistochemical examination of the cases confirmed myogenic differentiation, and showed rhabdoid cells being positive for vimentin and desmin in the inclusion bodies, and diffusely so for muscle actin in the cytoplasm. After dividing all the cases of leiomyosarcoma by their location, prognostic analysis was performed. Leiomyosarcoma of external soft tissue with rhabdoid cells showed a tendency for poorer prognoses than cases without rhabdoid features. On the contrary, retroperitoneal cases did not. This study indicates that rhabdoid features are associated with aggressive biological behavior in leiomyosarcoma of the external soft tissue.

Renal cell carcinoma with rhabdoid features

Neoplasms with rhabdoid features have been reported at many anatomic sites. In the kidney, rhabdoid tumors are typically found in children, whereas only rare examples have been reported in adults. Little is known of renal cell carcinomas (RCCs) that exhibit rhabdoid features. The objective of this study was to determine the incidence of RCC with rhabdoid attributes and characterize the histologic, immunophenotypic, and ultrastructural features by retrospective analysis of 480 consecutively identified cases of RCC in radical nephrectomy specimens. Immunohistochemical evaluation was performed in cases with rhabdoid foci using a panel of antibodies to pancytokeratin (pan-CK), CK7, CK20, epithelial membrane antigen (EMA), S-100 protein, desmin, vimentin, neuron-specific enolase (NSE), muscle-specific actin (MSA), smooth muscle actin (SMA), human melanoma, black-45 (HMB-45), and glial fibrillary acidic protein (GFAP). Electron microscopy was also performed in selected cases. The presence and extent of rhabdoid foci in relation to pathologic stage and grade were assessed. Twenty-three of 480 cases of RCC (4.7%) exhibited rhabdoid features. The 23 patients were all adults with a mean age of 61.8 years (age range, 33-84 yrs). Fifteen of the patients were men and eight were women. Histologically, the rhabdoid foci were typified by sheets and clusters of variably cohesive, large epithelioid cells with vesicular and often eccentric nuclei, prominent nucleoli, and large, paranuclear intracytoplasmic hyaline globules (inclusions). The presence of these rhabdoid features was related to high histologic Fuhrman grade of the nonrhabdoid carcinoma component, with an incidence of 0 of 84 grade I cases, eight of 300 grade 2 cases (2.6%), six of 70 grade 3 cases (8.9%), and nine of 26 grade 4 cases (34.6%; p = 3 x 10(-9)). The rhabdoid foci were all high grade. The presence of rhabdoid foci was also found in higher stage carcinomas. A total of 52% (12 of 23) of RCC cases with rhabdoid features exhibited extrarenal extension compared with 28% (24 of 92) of contemporary RCCs without rhabdoid features (p = 0.03). The size of the rhabdoid component ranged from 1 mm to more than 2 cm and comprised 1% to 50% of the renal mass. Immunoreactivity for vimentin (100%), NSE (79%), and panCK (56%) was present in the majority of cases. Substantial percentages of cases were immunopositive for EMA (47%) and S-100 protein (37%), with minimal to no immunohistochemical reactivity for CK7 (5%), SMA (5%), CK20 (0%), desmin (0%), MSA (0%), HMB-45 (0%), and GFAP (O%). A distinctive globular, paranuclear reaction pattern was found for the cytokeratin, EMA, and vimentin immunostains. Ultrastructurally, the rhabdoid cells had paranuclear intermediate filament aggregates or paranuclear condensation of organelles, often associated with peripheral vacuolization. Adult RCCs may harbor a rhabdoid component, and these neoplasms can be regarded as "composite" tumors. Rhabdoid elements are important to identify because of their high-grade nature, and association with high stage. Adult RCC with rhabdoid elements should be distinguished from pure rhabdoid tumors of kidney, in light of their clinicopathologic differences. Rhabdoid differentiation in adult renal cell carcinoma may represent clonal divergence and/ or evolution, and emergence of a particularly aggressive element.

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

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

Aspiration cytopathology of epithelioid angiosarcoma

BACKGROUND

Epithelioid angiosarcoma (EA) is an uncommon neoplasm readily mistaken for carcinoma. In contrast to the histopathology of this tumor, the cytopathology as obtained using fine-needle aspiration (FNA) biopsy has rarely been described.

METHODS

Three patients with histologically and immunohistochemically proven EA each underwent FNA using standard technique before surgical resection.

RESULTS

Aspirate smears were obtained from 3 males (ages 47, 63, and 15 years) each of whom presented with a solitary palpable soft tissue mass, 1 from the left calf and 2 from the right popliteal region. No patient had a history of malignancy or had been exposed to prior radiation therapy. Smears were relatively hypocellular due to the dilutional effects of abundant blood. Cells were scattered on slides primarily in a single cell dissociated pattern; small aggregates were present in a fraction of the slides. Malignant cells generally monotonous in size and averaging three to four times the dimension of a mature lymphocyte had a rounded so-called epithelioid configuration. Cells possessed primarily rounded, single nuclei often eccentrically placed, with some anisokaryosis, and smooth nuclear borders. Binucleated cells with mirror-image nuclei were much less frequent, and cells with three or four nuclei were even more scarce. Cells contained large single nucleoli or more often multiple misshapen smaller nucleoli. Cytoplasm was abundant and finely granular in virtually all cells. In some, the cytoplasm acquired a central spheric density thus producing a "rhabdoid" appearance that was only seen with air-dried Diff-Quik (Fisher Scientific, Biochemical Sciences, Inc., Swedesboro, NJ) stained smears. Mitoses were readily found. Immunostaining of the cell block in one case permitted a specific diagnosis of EA before subsequent surgical excision.

CONCLUSIONS

Epithelioid angiosarcoma may display a rhabdoid morphology in FNA biopsy smears, and this cytopathology can closely mimic that of nonsmall carcinoma, malignant melanoma, and other epithelioid types of soft tissue tumors. Immunophenotyping is essential for definitive diagnosis. Cancer (Cancer Cytopathol)

Epithelioid sarcoma of the penis: a case report and review of the literature

A rare case of epithelioid sarcoma (ES) of the penis is presented. The patient, a 35-year-old man, was initially treated as having Peyronie's disease, but the subsequent appearance of a subcutaneous nodule displayed a 'distal-type' ES. At immunohistochemical phenotypification, the tumor was positive for vimentin, cytokeratins and epithelial membrane antigen (EMA), as well as for some other multidirectional antibodies, including a membranous reaction for CD99. The review of 11 similar cases so far reported in the literature led to the conclusion that the clinicopathological characteristics of penile ES are basically the same as those of tumors in more classical locations: the age at diagnosis ranged from 23 to 43 years, the interval between first manifestations and diagnosis averaged 37 months (delayed diagnosis being common because of the slow growth rate and the harmless appearance of the lesion), the typical sign was a superficial nodule or mass, usually accompanied (better preceded) by urethral stenosis, dysuria and erectile disturbances. Total or partial penectomy was the treatment of choice in most patients, but lack of adequate follow up did not permit any definitive conclusion to be reached regarding its efficacy.