Uterine sarcomas

A wide variety of sarcomas occur in the uterus but two subtypes - leiomyosarcoma and endometrial stromal sarcoma - account for a majority of those more routinely encountered. Using the 2003 World Health Organization classification, this review focuses on six uterine sarcomas: endometrial stromal sarcoma, undifferentiated endometrial sarcoma, leiomyosarcoma, rhabomyosarcoma, angiosarcoma and liposarcoma. The epidemiological, clinical, pathological and molecular features are presented along with therapeutic approaches. Familiarity with molecular aspects of these tumors and application of novel technologies in their assessment should be encouraged as they may provide alternate therapies resulting in improved survival for the patient. Clinical information necessary for accurate diagnosis of these lesions is emphasised. A multidisciplinary approach to management of patients with uterine sarcomas is essential for optimal management.     

Primary brain sarcomas

The authors report on 79 cases of primary brain sarcomas, correlating clinical and pathoanatomical data. In the material analyzed the group of gliosarcomas prevailed, while the smallest group were rhabdomyosarcomas. In some groups the topic predilection did not show any specific characteristics, except that there were more gliosarcomas occurring in the parietal lobe. The symptoms lasted 1-3 months before operation.     

Low-grade sarcomas with CD34-positive fibroblasts and low-grade myofibroblastic sarcomas

A subset of low-grade fibrosarcomas is composed of CD34-positive spindle cells. These include dermatofibrosarcoma, its morphologic variants, and its associated fibrosarcoma, solitary fibrous tumor, hemangiopericytoma and their malignant counterparts, and some cases of myxoinflammatory fibroblastic sarcoma. Dermatofibrosarcoma and related lesions are characterized by a t(17;22)(q22;q13) rearrangement resulting in fusion of the genes COL1A (17q21-22) and PDGFB1 (22q13). Solitary fibrous tumor displays varying cellularity and fibrosis and a peripheral hemangiopericytomatous pattern; most tumors formerly called hemangiopericytoma are now subsumed into the category of solitary fibrous tumor, although a few strictly defined examples are recognized; however, these are probably not composed of pericytes. Myofibroblastic malignancies are best identified by electron microscopy, with which varying degrees of differentiation, including the presence of fibronexus junctions, can be identified. Low-grade sarcomas showing myofibroblastic differentiation include myofibrosarcomas and inflammatory myofibroblastic tumors. Myofibrosarcomas are spindle cell neoplasms that occur in children or adults in the head and neck, trunk, and extremities as infiltrative neoplasms and that display a fascicular or fasciitis-like pattern with focal nuclear atypia and variable expression of myoid antigens. These sarcomas are prone to recurrence and a small number metastasize. Inflammatory myofibroblastic tumor (synonymous with inflammatory fibrosarcoma) is a neoplasm arising predominantly in childhood, and frequently in intraabdominal locations. It has spindle cells in fascicular, fasciitis-like and sclerosing patterns, with heavy chronic inflammation including abundant plasma cells. Many IMT have clonal chromosomal abnormalities involving 2p22-24, and fusion of the ALK gene with tropomyosin 3 (TPM3-ALK) or tropomyosin 4 (TPM4-ALK) is found in a subset.     

Molecular testing of sarcomas

Connective tissue tumours, particularly sarcomas, are rare and present as a variety of histological subtypes with diverse management protocols and have varied prognoses. Many of these tumours have specific cancer driver genetic alterations that can be leveraged for diagnostic purposes. For practical purposes, these tumours can be categorised as harbouring genetic alterations including chromosomal rearrangements, gene amplifications, single nucleotide substitutions, and complex genetic abnormalities. Herein we discuss different tumour subtypes with their associated genetic abnormalities that may be used in clinical practice, when interpreted in the context of the relevant clinical, histological and radiological information.The benefits of large scale sequencing studies of sarcoma are leading to new insights into sarcoma development and are providing a biological rationale for personalised medicine. Genomic profiling and other “omic” studies will likely play a fundamental part in the development of new diagnostic and predictive biomarkers in the near future.     

Osteosarcomas and Ewing's sarcomas

Summary Primary malignant bone tumors, osteosarcomas (9 cases), and Ewing's sarcomas (10 cases) were examined for their reactivities with monoclonal and polyclonal antibodies against filamentous proteins and cell membrane determinants of the lymphoid and macrophage marker series. The reactivity of antibodies was studied on snap-frozen tissue probes by using a triple layer immunoperoxidase method. Osteosarcomas were positive for vimentin and, in part, for HLA-DR. Other types of intermediate-sized filaments were not detected in tumour cells. In a small number of cases (2/9) tumour cells were reactive with antibodies of the macrophage series (Leu M2).In Ewing's sarcomas, vimentin and HLA-DR was also demonstrated. It was particularly interesting that Leu M2 staining was found in the majority of cases (8/10). The staining pattern supports the assumption that this peculiar tumour is of mesenchymal (monocyte/macrophage) histogenesis.It was evident from the present study that, in primary osteogenic tumors, none of the examined tumour markers were as distinctive as they are for bone metastases. Nevertheless, the reactivity of Ewing's sarcoma cells with monoclonal antibodies of the Leu M2 type throws some highlights on the, as yet, obscure histogenesis of the neoplasm and may be of diagnostic value in conjunction with the known light and electron microscope features of the tumour.The study was supported by a grant of the Deutsche Forschungsgemeinschaft (Lo 285/2-2)     

Microarray analysis of sarcomas

Microarrays began to be used to study gene expression profiles in the mid-1990s, but it was only after 2000 that serious attempts have been made to apply this technology to investigate sarcomas. Microarray technologies provide a comprehensive survey of active molecular pathways and potential molecular targets for diagnosis and treatment, but are challenging to use because of issues of specimen collection, cost, and complexities in experimental design and data analysis. As a discovery-based technique, microarray analyses are most valuable when framed around specific gaps in our knowledge of tumor etiology and progression, challenges in differential diagnosis, and pressing therapeutic needs. To date, microarray analyses of sarcomas support their division into molecularly defined and molecularly heterogeneous categories, and have provided useful diagnostic markers for entities such as gastrointestinal stromal tumors, synovial sarcoma, and dermatofibrosarcoma protuberans. Signatures predicting outcome and response to therapy have been published for Ewing sarcoma and osteosarcoma, and receptor tyrosine kinase expression patterns have suggested novel therapeutic approaches which may be applied to several types of sarcoma. Nevertheless, results need to be interpreted in the context of histopathology and validated by complementary technologies and/or other research groups.     

Myofibroblasts in soft tissue sarcomas

Summary A series of 129 soft tissue sarcomas was examined ultrastructurally to determine in which neoplasms and to what extent myofibroblasts could be demonstrated. Twenty cases of fibromatosis and fasciitis served as controls.Myofibroblasts were identified in all 30 cases of malignant fibrous histiocytoma and all 4 cases of well-differentiated sclerosing liposarcoma. Though most numerous in areas of desmoplasia, in no instance did myofibroblasts constitute the dominant cellular constituent of either neoplasm. Myofibroblasts were identified with lesser frequency and in smaller numbers in fibrosarcoma, synovial sarcoma, malignant hemangiopericytoma and neuroblastoma. None were observed in a wide assortment of diverse sarcomas in which desmoplasia was not a feature. In comparison each lesion judged by light microscopy to represent either fibromatosis or fasciitis was composed principally of myofibroblasts.The demonstration of abundant myofibroblasts within a soft tissue lesion which has been subjected to wide sampling strongly suggests a benign proliferative process as opposed to a malignant neoplasm. It is hypothesized that myofibroblasts observed within collagenized regions of soft tissue sarcomas may constitute an expression of host response to neoplasia.     

Pediatric-type sarcomas in adult patients

Sarcomas included in the broad group of small round-cell tumors (SRCT) and some non-SRCT lesions that typically are seen in pediatric-age patients can rarely occur in adults. However, there are differences in the anatomic sites that are involved and the prognosis in these two patient groups. The diagnosis of pediatric-type sarcomas in adults is often challenging because of the unusual contextual clinical setting and morphologic features. Immunohistochemical studies have greatly facilitated this process. Moreover, limited biomolecular studies that have been conducted have demonstrated comparable cytogenetic alterations in adults and children with pediatric-type tumors. They also have raised interesting questions concerning possible biological bases for differences in clinical behavior in the two cohorts. This review focuses on the morphological, immunohistochemical, and molecular characteristics of childhood-type sarcomas that affect adults, with emphasis on possible pitfalls in differential diagnosis.     

Nucleolar organizer regions in uterine sarcomas

Summary Nucleolar organizer regions demonstrable by silver staining technique (AgNORs) are loops of nucleolar DNA transcribing to ribosomal RNA. This report quantifies AgNORs in normal endometrium and myometrium, and in leiomyomas and homologous sarcomas of the uterus. The mean AgNOR number in leiomyosarcomas was significantly higher than that in normal myometrium and that in leiomyomas, whereas no significant difference was observed between normal myometrium and leiomyomas. The mean AgNOR count in low-grade endometrial stromal sarcomas was significantly higher than that in normal endometrial stroma, and significantly lower than that in the high-grade variant of the same tumour. The epithelial component of malignant mixed müllerian tumours exhibited a significantly higher mean AgNOR number than normal endometrial epithelium, and the stromal component of these tumours showed a significantly higher mean AgNOR count than normal endometrial stroma and normal myometrium, respectively. The AgNOR count was significantly correlated with the mitotic rate in leiomyosarcomas, in high-grade endometrial stromal sarcomas, and in the epithelial and mesenchymal portions of mixed müllerian tumours, whereas no statistically significant correlation was observed in low-grade endometrial stromal sarcomas. Increased AgNOR counts have been reported for some kinds of malignant tumours in various organs, compared with normal tissues and benign tumours. This study demonstrates a similar increase when homologous uterine sarcomas are compared with histogenetically related normal and neoplastic tissues. AgNOR counting might be a useful adjunct in the classification and grading of uterine tumours.     

Primary cutaneous sarcomas showing rhabdomyoblastic differentiation

Rhabdomyosarcoma is a rare soft tissue neoplasm most commonly encountered in childhood and adolescence which has a predilection for the head and neck area, the genito-urinary tract and the extremities. Primary cutaneous presentation is extremely unusual and has been rarely reported in the literature. Herein, we describe two cases of rhabdomyosarcoma arising in the dermis of a 9-year-old girl and an 86-year-old man. Clinically, the tumours presented as solitary plaque-like or nodular lesions confined to the skin of the nose and chest wall, respectively. Histologically, the tumour in the first patient corresponded to an embryonal rhabdomyosarcoma. The tumour recurred locally four times, and in the last recurrence, showed features resembling those of malignant 'triton' tumour with fascicles of S-100 protein-positive spindle cells admixed with the rhabdomyoblastic components. The tumour in the second patient corresponded to the solid variant of alveolar rhabdomyosarcoma. Immunohisto-chemical studies in both tumours showed positive labelling for muscle-specific actin, desmin and vimentin. Ultrastructural examination in one case showed clusters of intermediate filaments in the cytoplasm recapitulating abortive sarcomeric structures consistent with rhabdomyoblastic differentiation. Both patients developed repeated recurrences over a period of 2–4 years despite adequate surgical excision, and the second patient had an axillary lymph node metastasis. Primary cutaneous rhabdomyosarcoma should be considered in the evaluation of small 'blue cell' tumours or undifferentiated malignant neoplasms of the skin, and appropriate immunohistochemical studies in conjuction with electron microscopy should be employed for proper evaluation of such lesions.