Ultrastructural heterogeneity in malignant fibrous histiocytoma of soft tissue

Five soft tissue sarcomas with histological features of malignant fibrous histiocytoma were selected to illustrate their ultrastructural heterogeneity. One case displayed the mixture of fibroblastic and histiocytic cells characteristic of the majority of malignant fibrous histiocytomas. In 1 case the tumor was composed entirely of primitive mesenchymal cells. The other 3 cases showed lipogenic, neurogenic, and "granular-cell" differentiation, respectively. These findings emphasize the important role of electron microscopy in the precise diagnosis and classification of malignant fibrous histiocytoma.     

FU-3 monoclonal antibody: a specific marker for malignant fibrous histiocytoma? An analysis of 32 malignant soft tissue and bone sarcomas

An immunohistochemical study on frozen sections was carried out on 51 malignant tumours of soft tissue and bone using the FU-3 monoclonal antibody. This antibody is claimed to be specific for malignant fibrous histiocytoma (MFH) and liposarcoma and for normal and tumour cells located in perivascular fields. The results show a lack of specificity in MFH staining: several malignant tumours such as synovial sarcoma, fibrosarcoma, rhabdomyosarcoma, osteogenic sarcoma, and including an anaplastic malignant melanoma, presented positive staining somewhat similar to that found in MFH. The value of this antibody in the differential diagnosis of MFH is doubtful. It might be useful to recognize a common pathway of terminal differentiation expressed by several pleomorphic sarcomatous neoplasms.This paper was presented in a short form at the XIX International Congress of the International Academy of Pathology, Madrid (18–23 October 1992).     

Reassessment and clinicopathological prognostic factors of malignant fibrous histiocytoma of soft parts

Recently, the category of malignant fibrous histiocytoma (MFH) has been under discussion and new entities resembling MFH have appeared. To clarify the recent situation regarding MFH, we reassessed previously diagnosed MFH cases in accordance with the most up-to-date diagnostic criteria, which included allied tumors. We carefully reassessed 428 cases that had been diagnosed in our institute during the past 28 years. Moreover, we searched for clinicopathological prognostic factors among the cases that were finally diagnosed as MFH. Among the 428 cases, 138 cases had their diagnoses changed. The revised cases included 78 leiomyosarcomas (57%; ordinary leiomyosarcoma, 45 cases; pleomorphic leiomyosarcoma, 23 cases; myxoid leiomyosarcoma, 10 cases), 12 liposarcomas (9%; pleomorphic liposarcoma, 11 cases; dedifferentiated liposarcoma, one case), seven dermatofibrosarcoma protuberans (5%), six unclassified sarcomas (4%), five primary or metastatic carcinomas (4%), four low-grade fibromyxoid sarcomas (3%), four inflammatory myofibroblastic tumors (3%), three rhabdomyosarcomas (2%), three malignant peripheral nerve sheath tumors (2%), three acral myxoinflammatory fibroblastic sarcomas (2%) and two atypical fibroxanthomas (1.5%). Among the 1974 soft tissue sarcomas registered in our institute, MFH (428 cases) had been the most common sarcoma, followed by liposarcoma, leiomyosarcoma and rhabdomyosarcoma. However, after reassessment, leiomyosarcoma proved to be the most common soft tissue sarcoma (322 cases), followed by 290 MFH, 273 liposarcomas and 202 rhabdomyosarcomas. Among these 290 cases finally diagnosed as MFH, survival data were available in 189 cases. Tumor location in the abdominal cavity, the retroperitoneum or the head and neck (P = 0.0024), tumor size of 5 cm or more (P < 0.0001), deep tumor location (P < 0.0001), high histological grade (grade 3) based on the French Federation of Cancer Centers' grading system (P = 0.0007), and high stage (stage III or IV) based on the American Joint Committee on Cancer (AJCC) staging system (P < 0.0001) were significantly worse prognostic factors by univariate analysis. In multivariate analysis, deep tumor location and high AJCC stage were independent adverse prognostic factors. We conclude that leiomyosarcoma is the most important differential diagnosis for MFH, especially pleomorphic leiomyosarcoma from storiform-pleomorphic type and myxoid leiomyosarcoma from myxoid type. Tumor depth and AJCC stage are the most important predictive prognostic factors in MFH.     

Characterization of human soft tissue sarcomas in nude mice. Evidence for histogenic properties of malignant fibrous histiocytomas.

Twenty-two human sarcomas were grafted subcutaneously into nude mice. Twelve tumors grew successfully. Nine of these 12 tumors had an aneuploid DNA content, whereas only 1 of 10 nonsuccessful tumors was aneuploid. The 12 sarcomas included two leiomyosarcomas, two malignant schwannomas, one synovial sarcoma, and seven malignant fibrous histiocytomas (MFHs). With light and electron microscopic and immunolabeling studies the original and xenografted tumors (the latter for at least two generations) were histopathologically compared. The xenografted leiomyosarcomas showed ultrastructurally a more pronounced leiomyodifferentiation, and one of the malignant schwannomas a more pronounced schwannian differentiation. The second malignant schwannoma and the synovial sarcoma, however, remained unchanged. Five storiform pleomorphic MFHs expressed features that were not observed in the original tumors. Tumor cells of three of these xenografted sarcomas showed leiomyogenic differentiation (filamentous densities, pinocytotic vescicles, and desmin immunoreactivity), whereas cells of the two others demonstrated schwannian differentiation (long cytoplasmic processes, basal lamina). A xenografted myxoid MFH and a pleomorphic MFH gave rise to pleomorphic sarcomas composed of undifferentiated cells. It appeared that under transplantation conditions tumor cells of storiform pleomorphic MFH can differentiate into various directions.     

Malignant soft tissue tumors (malignant fibrous histiocytoma, pleomorphic liposarcoma, and pleomorphic rhabdomyosarcoma): an electron microscopic study.

A comparative ultrastructural analysis of malignant soft tissue tumors (malignant fibrous histiocytoma, pleomorphic liposarcoma, and pleomorphic rhabdomyosarcoma) revealed similar ultrastructural features in this group of tumors. However, by electron microscopy these tumors can be differentiated on the basis of cytoplasmic and extracytoplasmic features (myosin filaments, lipid droplets, and perinuclear intermediate filaments, for example). This is even true of less well differentiated tumors and tumor cells. These findings support and amplify the concept of a common histogenesis for tumors of mesenchymal origin. Paradoxical features observed by light microscopy warrant further study by electron microscopy if the correct diagnosis is to be made in atypical cases, such as apparent malignant fibrous histiocytoma with cross striations.     

CD44 expression in soft tissue sarcomas

Recent studies have shown that expression of alternatively splicing variants of CD44 is correlated with prognosis for several kinds of malignant tumors. However, little is known about the expression of CD44 standard and variant isoforms in soft tissue sarcomas. In this study 47 cases of soft tissue sarcoma [18 malignant fibrous histiocytomas (MFHs), 13 synovial sarcomas (SSs), 7 malignant schwannomas (MSs), and 9 liposarcomas (LSs)] were examined immunohistochemically. The monoclonal antibodies to the standard form of CD44 (CD44H) and variant exons of CD44v3, 4, 5, 6, 7, 9, and v10 were used. We analyzed the membranous expression pattern of CD44H and CD44 variant exons and assessed the relation between expression of CD44s and metastasis-free survival rates (MFSR) of patients with soft tissue sarcoma. A few sarcomas expressed CD44v3 (2/47) and v7 (2/47), but none of the sarcomas expressed CD44v10. CD44v4 (5/47), v5 (4/47), v6 (10/47), and v9 (9/47) are relatively common types of variant isoforms in soft tissue sarcomas. Expression of CD44v6 is more frequently detected in high-grade than in low-grade tumors. CD44v6 or CD44v9 expression was correlated with metastasis-free survival of patients with soft tissue sarcomas. Received: 22 Juni 1999 / Accepted: 19 November 1999     

Gene expression analysis of human soft tissue leiomyosarcomas

Leiomyosarcoma of the somatic soft tissue is a rare malignant mesenchymal neoplasm that metastasizes to other organs in a subset of cases. Much remains to be learned about the mechanisms underlying the development of aggressive behavior of this tumor. It has been difficult to predict the clinical behavior of leiomyosarcomas using the morphology-based grading system, even though tumor size and histological grade have correlated with biologic behavior in some studies. In this study we analyzed the gene expression patterns of 35 samples of mesenchymal origin, including 11 cases of leiomyosarcomas of different histological grades arising in soft tissue and the retroperitoneum, using the Affymetrix U133a chips, which contain more than 22,000 genes and expression sequence tags (ESTs). We identified a set of genes whose expression was commonly altered in all leiomyosarcoma samples. In addition, we identified specific gene expression patterns in several subsets of the tumor. We used these alterations of gene expression to subclassify the leiomyosarcomas into 3 groups. Interestingly, the grouping of these samples correlated well with tumor differentiation and clinical aggressiveness. The analysis identified 92 genes that distinguish low-grade, well-differentiated leiomyosarcomas from less well-differentiated, high-grade, and metastatic leiomyosarcoma. Thesse alterations of gene expression appear to be correlated with the clinical behavior and histological grade of the tumor. The striking differences in terms of gene expression pattern among leiomyosarcomas of different differentiation status and clinical aggressiveness imply that several genetic abnormalities are responsible for the genesis and progression of this tumor.     

Immunohistochemical study of malignant fibrous histiocytoma

Malignant fibrous histiocytomas (MFH) and other soft-tissue tumors were examined immunochemically (by the peroxidase-antiperoxidase technique) for the presence and location of alpha 1-antitrypsin (alpha 1-AT) and alpha 1-antichymotrypsin (alpha 1-ACT). alpha 1-AT and alpha 1-ACT were found in substantial amounts in 19 and 20 of the 20 MFH tumors examined, respectively. In the other soft-tissue tumors, they occurred inconsistently and in less than 50% of cells, mostly those with signs of damage. It is concluded that assays for alpha 1-AT and alpha 1-ACT may aid in the diagnosis and characterization of malignant fibrous histiocytoma.     

Ultrastructural features of malignant fibrous histiocytoma of bone.

Five cases of malignant fibrous histiocytoma originating in the femur and tibia, sometimes with local recurrences, are reported. Histological and clinical characteristics of this lesion were similar to those in soft tissues with the same disease. The present histiocytomas were observed by electron microscopy and shown to consist of 5 types of neoplastic cells which were regarded as undifferentiated cells, histiocyte-like cells, which were predominating, fibroblast-like cells, multinucleated giant cells and xanthomatous cells. These findings led us to confirm the existence of malignant fibrous histiocytoma originating in bone as well as in soft tissues.     

腹膜后恶性纤维组织细胞瘤的 MSCT 表现及诊断价值简

目的分析腹膜后恶性纤维组织细胞瘤（MFH）的多层螺旋CT（MSCT）表现,探讨MSCT对该病的诊断价值。方法经手术病理证实的15例腹膜后MFH患者,其中男性11例,女性4例：年龄21～79岁,平均年龄46.5岁。回顾性分析其临床及MSCT表现.并与病理组织学改变相对照。结果15例腹膜后MFH主要临床表现为腹部肿块和疼痛。15例MSCT平扫表现为腹膜后软组织肿块.肿瘤呈圆形或类圆形10例。不规则形5例,肿瘤平均直径为12.5cm,瘤内坏死9例,出血7例,钙化6例。增强扫描肿瘤不均匀强化,13例见分隔状强化。组织学上呈明显多形性,其中车辐状一多形型MFH 11例,巨细胞型MFH 3例,炎症型MFH 1例。结论腹膜后MFH的MSCT表现具有一定特征,对其诊断及鉴别诊断有重要价值。     

Radiation-induced inflammatory malignant fibrous histiocytoma of the ileum.

A case of inflammatory malignant fibrous histiocytoma of the ileum seemingly induced by radiation is described. A 50-year-old female with a past history of uterine cervical carcinoma and postoperative radiation therapy presented with abdominal pain, fever and leukocytosis. The subserosa of the distal part of the ileum showed a diffuse dense, neutrophilic and lymphocytic infiltrate with dispersed atypical, short spindle- or plump oval-shaped histiocyte-like cells. Pleomorphic mono- or multinucleated giant cells with bizarre nuclei were also intermingled in the lesion. Immunohistochemically, the tumorous atypical cells were positive for vimentin, alpha-smooth muscle actin, alpha-1 antitrypsin and granulocyte colony-stimulating factor. No EBV genomic sequences were detected by in situ hybridization. Flow cytometry showed an aneuploid DNA content with high S-phase fraction. The patient was well with no evidence of tumor at 5 months after surgery. It is important to include this type of tumor in the differential diagnosis of small intestinal lesions accompanied by fever and leukocytosis following radiation.     

Beta-catenin in soft tissue sarcomas: expression is related to proliferative activity in high-grade sarcomas.

Besides its role in cell adhesion, beta-catenin exerts a function as an oncoprotein. The aim of this study was the characterization of its expression, possible mutation, and the assessment of beta-catenin as a prognostic indicator for soft tissue sarcomas. A total of 115 soft tissue sarcomas were analyzed using immunohistochemistry, immunogold-electron microscopy, and DNA analysis. Information from 56 patients was available for follow-up. A statistically significant correlation was found between intracellular distribution of beta-catenin and the proliferative activity (MIB-1 expression) in high-grade sarcomas (P = .0008). Beta-catenin was identified with intracytoplasmic and nuclear accumulation, showing additional membranous staining in sarcomas with epithelioid pattern. Ultrastructurally, a colocalization between beta-catenin and nuclear heterochromatin was demonstrated. In 22 analyzed tumors, only one (yet undescribed) mutation of the beta-catenin gene (C-A transversion) could be detected. Prognostic validity of the cellular expression of beta-catenin, however, was not proven. Apart from its membranous function as an effective molecule for cell-adhesion in sarcomas with epithelioid pattern, beta-catenin may act as an oncoprotein in sarcomas with intracytoplasmic and nuclear localization with binding to nuclear DNA. A previously discussed stimulation of cell proliferation caused by an increased beta-catenin level can also be postulated for high-grade soft tissue sarcomas in correlation with the rate of proliferation. Mutations of the beta-catenin gene are probably of lesser importance for the accumulation of beta-catenin in soft tissue sarcomas.     

Radiation-induced malignant fibrous histiocytoma of the pulmonary artery.

We describe a malignant fibrous histiocytoma (MFH) of the pulmonary artery. The patient received, 25 years ago, at the age of 43 years, radiation therapy to the chest for squamous-cell carcinoma of the lung. We believe the patient's second tumor was induced by radiation and, to our knowledge, this case represents the first report of radiation-induced MFH of the pulmonary artery. The diagnosis was confirmed by findings from electron microscopy and extensive studies with immunohistochemical stains. We discuss the value of studies with immunohistochemical stains in the diagnosis and differential diagnosis of MFH. The presentation of this case underlines that MFH can occur in the pulmonary artery and may be--as is the MFH in other locations--induced by radiation.     

Malignant fibrous histiocytoma of the soft tissues

Clinico-morphological characterization of the malignant fibrous histiocytoma (MFH) of soft tissues in 142 patients is presented. According to the authors' data MFH is the most frequent tumour among soft tissue malignant neoplasms (15,7%) in adult patients. The age of patients is predominantly from 40 to 70, the most frequent site is a lower limb (thigh). A typical morphological variant of MFH clearly dominates (73%): there is a tendency to the development of an inflammatory variant at the retroperitoneal tumour site. Recurrences in all group of patients (104) who were followed-up were in 68,3%, metastasis in 45,2%, the 5-year survival in 59,6% of cases. A clear-cut dependence of these indices upon the depth of tumour location soft tissues, node size, tumour site is noted. In view of pronounced domination of a MFH typical variant the final conclusion on the feasibility of separation of other variants can be only made on the basis of a much greater number of cases.     

Pleural malignant fibrous histiocytoma concomitant with pulmonary adenocarcinoma.

A rare autopsy case, in which pleural malignant fibrous histiocytoma (MFH) and peripheral pulmonary adenocarcinoma were present concurrently in the right thorax, is described. Clinically, only a pleural mass was detected because of massive pleural effusion. Since cytologic examination of the effusion showed only adenocarcinoma cells, the pleural mass was considered to be enlarged mediastinal lymph nodes due to metastasis of adenocarcinoma. Histopathologically, the pleural mass showed the features of a common type of MFH, accompanied by metastatic adenocarcinoma cells in the pleural lymphatics. No mixture of MFH and adenocarcinoma cells was present. Immunohistochemically, the MFH lesion showed positive staining for alpha-1-antitrypsin, alpha-1-chymotrypsin, and factor XIIIa, but no reactivity for cytokeratins. The adenocarcinoma lesion showed positive staining for carcinoembryonic antigen (CEA), and contained hyaluronidase-resistant mucin. To our knowledge, this is the second reported case of pleural MFH with pulmonary adenocarcinoma.