Riesenzelltumoren des Weichgewebes (mit niedrig-malignem Potenzial) in Operationsnarben

Giant cell tumor of soft tissue (GCT-ST) is a rare primary soft tissue tumor with low malignant potential. It is clinically and pathologically similar to the giant cell tumor of the bone. Two cases of GCT-ST in surgical scars are reported. Both tumors were initially regarded as tumor relapses of a leiomyosarcoma of deep soft tissue and a dermal in situ squamous cell carcinoma, respectively. The development of GCT-ST in surgical scars has not been observed previously. These findings suggest chronic inflammation and tissue repair as etiological factors in the development of GCT-ST. The period of time between initial surgical intervention and the development of the GCT-ST seems to be unusually short for the development of a “true” second neoplasm, which may underline the sometimes diffuse border between reactive “pseudosarcomatous” and neoplastic fibro-histiocytic lesions.     

Giant cell tumor of soft tissue arising in breast

Primary giant cell tumor of soft tissue (GCT-ST) arising in breast is exceedingly rare. We report a case of a 60-year-old woman with a primary breast giant cell tumor that appeared histologically identical to giant cell tumor of bone and had a clinically malignant course. The patient presented with a cystic mass of the breast, suspected on imaging to be an organizing hematoma, possibly related to previous injury. Histopathological evaluation revealed a neoplasm composed of mononuclear cells admixed with osteoclast-like giant cells resembling giant cell tumor of bone. Immunohistochemical staining was positive for CD68, smooth muscle actin, and vimentin, but was negative for a panel of epithelial and additional muscle markers. These features were most consistent with GCT-ST, an uncommon neoplasm of low malignant potential. Despite aggressive surgical treatment achieving clear surgical margins, the patient expired with pulmonary metastases within a year of her initial presentation. This case demonstrates the difficulty of predicting clinical behavior of GCT-ST of breast on the basis of histological features and depth of tumor alone. To our knowledge, this is the first case report of a GCT-ST arising in the breast associated with a fatal outcome. The distinction of this entity from other more common primary breast tumors with giant cell morphology is also emphasized.     

Giant cell tumor of soft tissue of the breast: Case report with H3F3A mutation analysis and review of the literature

Giant cell tumors of soft tissue (GCT-ST) arising in the breast are extremely rare. We report a unique case of breast GCT-ST coincident with ductal carcinoma in situ (DCIS), diagnosed with histological, immunohistochemical, and H3F3A (Histone H3.3) mutation analyses. A 59-year-old woman preoperatively diagnosed with DCIS underwent total mastectomy for a cystic mass. Histology revealed a tumor composed of mononuclear cells interspersed with numerous osteoclast-like giant cells, resembling giant cell tumor of bone (GCT-B), with apocrine DCIS in proximity to the tumor. The mononuclear and giant cells were immunoreactive for CD68 and negative for cytokeratins. Granulomatous diseases, carcinomas with giant cells, and giant cell-type sarcomas were excluded by histological and immunophenotypic features. Lack of H3F3A mutation eliminated the possibility of GCT-B metastasizing to the breast. These findings were consistent with GCT-ST of the breast. To our knowledge, this is the ninth reported case of breast GCT-ST, but the first case that accompanied DCIS or involved H3F3A mutation status investigation. For correct diagnosis of this rare tumor, it is important for pathologists to raise the possibility of GCT-ST when encountering giant cell-rich breast lesions and to exclude other differential diagnoses by combining the results of histological, immunohistochemical, and genetic analyses.     

Primary malignant giant cell tumor of bone: "dedifferentiated" giant cell tumor

Well documented examples of primary malignant giant cell tumor of bone (giant cell tumor and concurrent sarcoma arising de novo) are exceedingly rare in the literature. We report a case arising in the left ischium of a 44-yr-old man. He had no previous history of radiation therapy or multiple resections. Histologically, the tumor was a typical giant cell tumor of bone juxtaposed to a malignant fibrous histiocytoma (MFH). The juxtaposition of a high grade sarcoma (MFH) and a locally aggressive nonmalignant neoplasm such as giant cell tumor is analogous to several other tumors of bone and soft tissue in which a low grade malignant or locally aggressive tumor can be associated with MFH or fibrosarcoma de novo, namely chondrosarcoma, chordoma, liposarcoma, and well differentiated intraosseous and parosteal osteosarcoma. The presence of a high grade malignant component in each of the aforementioned neoplasms generally portends a more ominous prognosis, although this is not invariably true. Recognition of the phenomenon of "dedifferentiation" (or tumor progression) in some bone tumors and sarcomas is important to ensure appropriate treatment. Distinction from secondary malignant giant cell tumors which are usually radiation induced is also important, since the latter have a much worse prognosis than those with dedifferentiation occurring de novo.     

The Comparative Role of Immunohistochemistry and Electron Microscopy in the Identification of Myogenic Differentiation in Soft Tissue Pleomorphic Sarcomas

There is increasing evidence that histological classification of pleomorphic soft tissue sarcomas is prognostically useful, since a number of studies have provided evidence that myogenic differentiation is associated with a more aggressive clinical behavior. The aim of the current study was to analyze the role of electron microscopy in comparison with immunohistochemistry in the classification of soft tissue pleomorphic sarcomas. Thirty-nine pleomorphic sarcomas of the somatic soft tissues for which material for immunohistochemical and ultrastructural analysis was available were selected for this study. Cases were classified according to the criteria of the WHO classification of soft tissue tumors on the basis of the histologic appearance and of the results of immunohistochemical analysis, and then diagnoses were reconsidered at the light of the results of the ultrastructural analysis. The group of myogenic sarcomas included 13 leiomyosarcomas, 8 myofibrosarcomas, and 1 rhabdomyosarcoma, while the group of nonmyogenic sarcomas included 11 undifferentiated pleomorphic sarcomas/malignant fibrous histiocytomas (MFH), 4 myxofibrosarcomas, and 2 liposarcomas. Overall, there was a good concordance between immunohistochemistry and electron microscopy in recognizing myogenic differentiation in soft tissue pleomorphic sarcomas. Discrepancies included 1 case showing no immunoreactivity for muscle markers, which displayed ultrastructural features allowing reclassification as leiomyosarcoma, and 2 cases initially classified as undifferentiated pleomorphic sarcoma/MFH, which were reclassified as myofibrosarcomas after ultrastructural analysis. Ultrastructural analysis allowed the identification of pleomorphic sarcomas with myofibroblastic phenotype, a category that is not identifiable based on histologic and immunohistochemical profile. Notably, fibronexus junction was identified in tumor cells of 4 pleomorphic myofibrosarcomas, while 2 other lesions showed putative fibronexus junction structures, consisting of electron-dense straight fibrils adjacent to the cell surface, not clearly in continuity with cytoplasmic actin filaments. In conclusion, the results indicate that immunohistochemistry and electron microscopy can usefully complement each other in the classification of soft tissue pleomorphic sarcomas.     

The comparative role of immunohistochemistry and electron microscopy in the identification of myogenic differentiation in soft tissue pleomorphic sarcomas

There is increasing evidence that histological classification of pleomorphic soft tissue sarcomas is prognostically useful, since a number of studies have provided evidence that myogenic differentiation is associated with a more aggressive clinical behavior. The aim of the current study was to analyze the role of electron microscopy in comparison with immunohistochemistry in the classification of soft tissue pleomorphic sarcomas. Thirty-nine pleomorphic sarcomas of the somatic soft tissues for which material for immunohistochemical and ultrastructural analysis was available were selected for this study. Cases were classified according to the criteria of the WHO classification of soft tissue tumors on the basis of the histologic appearance and of the results of immunohistochemical analysis, and then diagnoses were reconsidered at the light of the results of the ultrastructural analysis. The group of myogenic sarcomas included 13 leiomyosarcomas, 8 myofibrosarcomas, and 1 rhabdomyosarcoma, while the group of nonmyogenic sarcomas included 11 undifferentiated pleomorphic sarcomas/malignant fibrous histiocytomas (MFH), 4 myxofibrosarcomas, and 2 liposarcomas. Overall, there was a good concordance between immunohistochemistry and electron microscopy in recognizing myogenic differentiation in soft tissue pleomorphic sarcomas. Discrepancies included 1 case showing no immunoreactivity for muscle markers, which displayed ultrastructural features allowing reclassification as leiomyosarcoma, and 2 cases initially classified as undifferentiated pleomorphic sarcoma/MFH, which were reclassified as myofibrosarcomas after ultrastructural analysis. Ultrastructural analysis allowed the identification of pleomorphic sarcomas with myofibroblastic phenotype, a category that is not identifiable based on histologic and immunohistochemical profile. Notably, fibronexus junction was identified in tumor cells of 4 pleomorphic myofibrosarcomas, while 2 other lesions showed putative fibronexus junction structures, consisting of electron-dense straight fibrils adjacent to the cell surface, not clearly in continuity with cytoplasmic actin filaments. In conclusion, the results indicate that immunohistochemistry and electron microscopy can usefully complement each other in the classification of soft tissue pleomorphic sarcomas.     

The Comparative Role of Immunohistochemistry and Electron Microscopy in the Identification of Myogenic Differentiation in Soft Tissue Pleomorphic Sarcomas

There is increasing evidence that histological classification of pleomorphic soft tissue sarcomas is prognostically useful, since a number of studies have provided evidence that myogenic differentiation is associated with a more aggressive clinical behavior. The aim of the current study was to analyze the role of electron microscopy in comparison with immunohistochemistry in the classification of soft tissue pleomorphic sarcomas. Thirty-nine pleomorphic sarcomas of the somatic soft tissues for which material for immunohistochemical and ultrastructural analysis was available were selected for this study. Cases were classified according to the criteria of the WHO classification of soft tissue tumors on the basis of the histologic appearance and of the results of immunohistochemical analysis, and then diagnoses were reconsidered at the light of the results of the ultrastructural analysis. The group of myogenic sarcomas included 13 leiomyosarcomas, 8 myofibrosarcomas, and 1 rhabdomyosarcoma, while the group of nonmyogenic sarcomas included 11 undifferentiated pleomorphic sarcomas/malignant fibrous histiocytomas (MFH), 4 myxofibrosarcomas, and 2 liposarcomas. Overall, there was a good concordance between immunohistochemistry and electron microscopy in recognizing myogenic differentiation in soft tissue pleomorphic sarcomas. Discrepancies included 1 case showing no immunoreactivity for muscle markers, which displayed ultrastructural features allowing reclassification as leiomyosarcoma, and 2 cases initially classified as undifferentiated pleomorphic sarcoma/MFH, which were reclassified as myofibrosarcomas after ultrastructural analysis. Ultrastructural analysis allowed the identification of pleomorphic sarcomas with myofibroblastic phenotype, a category that is not identifiable based on histologic and immunohistochemical profile. Notably, fibronexus junction was identified in tumor cells of 4 pleomorphic myofibrosarcomas, while 2 other lesions showed putative fibronexus junction structures, consisting of electron-dense straight fibrils adjacent to the cell surface, not clearly in continuity with cytoplasmic actin filaments. In conclusion, the results indicate that immunohistochemistry and electron microscopy can usefully complement each other in the classification of soft tissue pleomorphic sarcomas.     

Expression of Met/hepatocyte growth factor receptor gene and malignant behavior of musculoskeletal tumors.

Overexpression of the hepatocyte growth factor receptor (Met/HGF receptor), a transmembrane tyrosine kinase encoded by the met proto-oncogene, has been associated with tumor progression in different human carcinomas. More recently, the Met/HGF receptor has also been described in tumor cell lines of mesenchymal origin, suggesting the existence of an autocrine loop that may contribute to the pathogenesis of sarcomas. In this study, we analyzed the expression of Met/HGF receptor by Western blotting and immunohistochemistry in frozen samples of 87 primary tumors of bone and soft tissues. Among benign tumors, overexpression was consistently found only in giant-cell tumor, a locally aggressive lesion that may also, although rarely, spread to the lung. Among malignant lesions, the presence of the Met/HGF receptor was detected in a relevant percentage of primaries and in almost all of the recurrences. The highest levels of Met/HGF receptor were found in osteosarcoma, a highly aggressive tumor that typically permeates the host bone and rapidly expands to the soft tissues. On the contrary, only low levels of Met/HGF receptor were found in chondrosarcoma, a slowly growing tumor that usually expands without massive destruction of the surrounding structures. These data indicate an association of Met/HGF expression with local aggressiveness in human mesenchymal tumors. The finding of Met/HGF receptor overexpression in all of the osteosarcomas suggests a role for the met proto-oncogene in the pathogenesis of this tumor.     

Genomic characteristics of soft tissue sarcomas

Studies on the molecular mechanisms behind soft tissue sarcoma development have disclosed that these malignancies are as genetically heterogeneous as they are clinically and morphologically diverse. Much of the genetic information on soft tissue sarcomas is still limited to the genomic level, as detected by chromosome banding analysis or comparative genomic hybridization. Based on the results of such studies, soft tissue sarcomas may be broadly dichotomized into one group, accounting for approximately 20% of the cases, characterized by specific balanced translocations, and one group typically showing massive chromosomal rearrangements leading to recurrent, but non-specific, structural and numerical rearrangements. As summarized in this review, the genomic characterization of soft tissue sarcomas has not only provided cell biologists with decisive information on the parts of the genome that may harbor genes that are essential for tumor development but also given the clinicians involved in the management of these patients a valuable diagnostic tool.     

Uterine stromal neoplasms: a clinicopathologic and DNA flow cytometric correlation

Twenty-five uterine stromal neoplasms (five stromal nodules and 12 low-grade and eight high-grade stromal sarcomas) were studied to determine the correlation between clinicopathologic features, flow cytometric tumor DNA content and proliferative fraction, and patient outcome. Fifteen of the 20 sarcomas (five of them high grade) were confined to the uterus (stages I and II); the other five (two low grade and three high grade) extended outside the uterus (stages III and IV). Stromal nodules and low-grade sarcomas manifested diploid DNA content and low proliferative index. All stromal nodules and the majority of low-grade sarcomas pursued a benign clinical course. Two cases of low-grade sarcoma ran a malignant course; both patients had high-stage disease. Three of the high-grade sarcomas were diploid and five were aneuploid. All eight neoplasms demonstrated high proliferative index and seven ran a malignant course (four of five were stage I and three of three were stage IV). Three high-grade stage I tumors had a low mitotic rate but a high proliferative index and ran an aggressive course. All high-stage sarcomas were clinically aggressive, irrespective of their histologic classification or DNA characteristics. The proliferative index by flow cytometry may offer an objective adjunct in predicting the aggressive potential of a subset in low-stage neoplasms.     

Malignant hemangiopericytoma and other sarcomas with hemangiopericytoma-like pattern

This clinicopathologic study concerns 19 cases of malignant hemangiopericytoma among 755 cases of soft tissue sarcomas. The age of the patients ranged from 18 to 76 years, with a median of 43 years. Tumors occurred on the trunk in 8, lower extremities in 5, the head in 3, and the retroperitoneum in 3. According to follow-up information, nine of the 19 patients had died. Histologically the tumor was characterized by its homogeneous vascular pattern, its uniform cell population and a wide range of cellular anaplasia. After extensive sampling of the tumors, a comparative light microscopy revealed differences in diagnostic histology between malignant hemangiopericytoma and other soft tissue sarcomas with a hemangiopericytoma-like vascular pattern. The frequency of appearance of such pericytoma pattern in different soft tissue sarcomas was as follows: 4/4 cases (100%) in extraskeletal mesenchymal chondrosarcoma, 11/14 (79%) in infantile fibrosarcoma, 27/45 (60%) in synovial sarcoma, 62/201 (30%) in malignant fibrous histiocytoma, 9/37 (25%) in malignant schwannoma and 6/72 (8%) in liposarcoma.     

Undifferentiated and poorly differentiated carcinoma

Undifferentiated (anaplastic) thyroid carcinoma is a highly aggressive neoplasm which may simulate microscopically a variety of soft tissue sarcomas. The three major subtypes are spindle cell, giant cell, and squamoid. Electron microscopic examination and immunocytochemical stain for cytokeratin are the most useful special techniques to document the epithelial nature of the tumor. Undifferentiated small-cell carcinoma is a term to be discarded. Nearly all tumors so designated in the past are malignant lymphomas, small-cell variants of medullary carcinomas, or poorly differentiated (insular) carcinomas. Poorly differentiated (insular) carcinoma is a thyroid malignant tumor characterized by the formation of solid nests and small follicles, a monotonous growth of small cells of follicular derivation, mitotic activity, necrosis, and peritheliomatous formation. Immunocytochemically, it is negative for calcitonin and positive for thyroglobulin. It is a clinically aggressive neoplasm, which metastasizes to both regional lymph nodes and distant organs. It is probably analogous to the tumor described by Langhans in 1907 as "wuchernde Struma."     

DNA hypermethylation status of multiple genes in soft tissue sarcomas.

The aberrant methylation of promoter CpG islands is known to be a major inactivation mechanism of tumor-related genes. To determine the clinicopathological significance of gene promoter methylation in soft tissue sarcomas, we examined the promoter methylation status of 10 tumor-related genes in 65 soft tissue sarcomas and 19 adjacent non-neoplastic tissues by methylation-specific PCR. The methylation frequencies of tumor-related genes tested in soft tissue sarcomas were 17 (26%) for RASSF1A, 11 (17%) for DAP kinase, 10 (15%) for MGMT, nine (14%) for GSTP1, eight (12%) for PTEN, six (9%) for p16 and hMLH1, five (8%) for hMSH2, two (3%) for p14, and one (2%) for RB. Promoter methylation of these genes was not recognized in non-neoplastic tissues. All those cases of soft tissue sarcoma that had MGMT methylation, with the exception of one case of malignant peripheral nerve sheath tumor, showed large tumor size (> or = 10 cm) or recurrence. Moreover, eight of 10 cases with MGMT methylation revealed high American Joint Committee on Cancer stage. Seven of 10 cases (70%) with MGMT methylation showed a loss of MGMT expression by immunohistochemistry. In addition, MGMT methylation status had a statistically significant correlation with a loss of MGMT expression (P=0.014). In conclusion, although methylation of tumor-related genes was a relatively rare event in soft tissue sarcomas, methylation was tumor-specific. Of 10 tumor-related genes, cases with MGMT methylation had a tendency to be aggressive behavior. Moreover, MGMT methylation was closely associated with a loss of MGMT expression. Although our findings need to be extending to a large series, promoter methylation of tumor-related genes is likely to have an association with the pathogenesis of soft tissue sarcomas. Furthermore, MGMT methylation may be associated with tumor aggressiveness and the inactivation of MGMT gene.     

Ultrastructural studies in the preoperative cytologic diagnosis of soft tissue tumors

A consecutive series of 100 patients operated on for lesions that were assumed to be soft tissue tumors, all of whom had been the subject of fine-needle aspiration in the preoperative investigation, is described. A correlative study of smears and the light- and electron-microscopic findings of embedded fine-needle aspirates and the histopathology of the surgical specimens was performed. Eighty of the lesions were found to be genuine soft tissue tumors, of which 51 were sarcomas. The other 20 cases were either metastatic carcinoma, malignant melanoma, or malignant lymphoma. The embedding technique produced additional light-microscopic information about tissue structure and growth pattern, and electron-microscopic information about tissue and cell differentiation of importance to the diagnosis. In the case of certain types of soft tissue tumor, such as lipoma, neurilemmoma, liposarcoma, and malignant fibrous histiocytoma, and for well-differentiated metastatic carcinoma and pigmented malignant melanoma, the diagnosis may be strongly suggested by the appearance of the smears; the embedding technique serves to further support the diagnosis. In the case of small round-cell malignancies, the ultrastructural examination proved to be of special value, ie, in the distinction of rhabdomyosarcoma, poorly differentiated metastatic small cell carcinoma and malignant melanoma, and occasional cases of malignant lymphoma. Spindle cell sarcomas, such as leiomyosarcoma when well differentiated, biphasic synovial sarcoma when it includes glandular structures, and malignant hemangiopericytoma, could be recognized ultrastructurally, although electron-microscopy generally failed to reach a definite diagnosis as to the subtype in most cases of poorly differentiated spindle-cell sarcoma.     

Aggressive angiomyxoma presenting as polyp of uterine cavity

Aggressive angiomyxoma is a distinctive, locally aggressive tumor associated with a high risk of local recurrences that lacks metastatic potential. This tumor occurs mostly in the soft tissues of the pelvis and the perineum of adult women. It may rarely occur at less common sites, such as the vagina, urinary bladder, and soft tissue of the perineum and the perianal region in men, particularly the scrotum. We report a case of aggressive angiomyxoma presenting as an endometrial uterine polyp. To the best of our knowledge, the primary location of aggressive angiomyxoma within the uterine cavity has never been described. Immunohistochemical and ultrastructural findings support the conclusion that the progenitor cell displays myofibroblastic and fibroblastic features, with a capacity for smooth muscle differentiation.     

Aquaporin-1 and -5 are involved in the invasion and proliferation of soft tissue sarcomas

Background and aim

Recent studies of several carcinomas have reported that aquaporin possesses novel oncogenic properties. The aim of this study was to clarify the involvement of aquaporin-1 and ?5 in the proliferation, invasion and metastasis of soft tissue sarcomas.

Sklerosierendes epitheloides Fibrosarkom

The sclerosing epithelioid fibrosarcoma (SEF), defined as an entity by Meis-Kindblom et al. in 1995 [15] is now considered to be a variant of fibrosing fibrosarcomas. It is a rare tumor with an intermediate malignant potential leading to local recurrences in one third and to metastases in about 40% of the cases. We report six cases of this entity. At the time of diagnosis two patients of our series already showed metastases in the lungs. The tumors were located in the deep soft tissue and measured between 2.5 and 17 cm. The histology is characterized by small epithelioid cells that are arranged individually or in cords and nests and set typically in a hyaline sclerotic matrix. By immunohistochemistry, all cases were vimentin positive, however EMA positive cells are also possible. The differential diagnosis includes metastases of carcinoma, benign and malignant soft tissue tumors. The distinction of SEF from fibromatosis, fibrous histiocytomas, ossifying fibromyxoid tumors, clear cell sarcomas, epithelioid sarcomas, synovial sarcomas and extraskeletal osteosarcomas is discussed.     

HLA-DR (Ia-like) reactivity in tumors of bone and soft tissue: an immunohistochemical comparison of monoclonal antibodies LN3 and LK8D3 in routinely processed specimens.

Recent studies of Class II histocompatibility antigen expression in bone and soft tissue sarcomas have suggested that malignant fibrous histiocytoma (MFH) may express HLA-DR, whereas histologically similar pleomorphic, epithelioid, and spindle cell malignant neoplasms generally do not. To test whether these observations are reproducible in the differential diagnosis of soft tissue sarcomas, anti-HLA-DR antibodies LK8D3 and LN3 were applied to formalin-fixed, paraffin-embedded sections of MFH, neurofibrosarcoma (NFS), leiomyosarcoma (LMS), synovial sarcoma (SS), fibrosarcoma (FS), angiosarcoma (AS), Kaposi's sarcoma (KS), chondrosarcoma (ChS), "dedifferentiated" chondrosarcoma (DChS), osteosarcoma (OS), epithelioid sarcoma (ES), and clear cell sarcoma (CCS; malignant melanoma of soft parts). The only consistent difference in Class II antigen expression was seen in the group of neoplasms composed of large polygonal cells. Among the latter lesions, four of six clear cell sarcomas were labeled by LK8D3 or LN3, but none of 12 epithelioid sarcomas were reactive. Otherwise, a diversity of tumors in other morphologic categories expressed Class II antigens, with no clear diagnostic patterns. These results may be of use in the diagnostic separation of large cell epithelioid tumors of soft tissue, but neither LN3 nor LK8D3 appears to be helpful in the identification of other sarcomas.