Malignant peripheral nerve sheath tumor with perineurial cell differentiation (malignant perineurioma)

A unique case of malignant peripheral nerve sheath tumor (MPNST) with perineurial cell differentiation occurring in a 63-year-old woman in a subcutis of the forearm is described. The tumor contained cellular and myxoid areas. The neoplastic cells were fusiform with distinct cell borders. They were arranged in storiform pattern and in wavy parallel cell cords in the cellular areas. Focally, a pleomorphism and mitotic activity (including atypical mitoses) similar to those of malignant fibrous histiocytoma were seen. The myxoid parts contained haphazardly oriented cells and scarce lipoblast-like multivacuolated cells mimicking a liposarcoma. In the differential diagnosis, myxoid liposarcoma, dermatofibrosarcoma protuberans, malignant fibrous histiocytoma and low-grade fibromyxoid sarcoma were considered. Immunohistochemically, perineurial differentiation was indicated by the diffuse expression of epithelial membrane antigen and focal reactivity for CD34. The tumor was negative with antibodies to S-100 protein, Leu-7, CD68 (KP1), vimentin and cytokeratin AE1/AE3. Ultrastructure of tumor cells revealed features of MPNST. No recurrence occurred in the patient during 2 years follow up.     

Different mRNA expression profile during tumor progression in a well-differentiated liposarcoma--A microdissection approach

Like malignant fibrous histiocytoma (MFH), dedifferentiated liposarcoma represents a distinct subtype of liposarcoma and is characterized by an abrupt transition from well-differentiated liposarcoma (WDL) to highgrade dedifferentiated liposarcoma (DDL) . In addition, specific cytogenetic aberrations support the close biological relationship between WDL and DDL. Recent observations indicated the significance of cell cycle aberrations in tumor progression from the low-malignant, well differentiated to its dedifferentiated form, the prognosis of which is poor. Thus, alterations of mdm2 and p53 genes belong to the most frequently reported alterations in these two subtypes of liposarcoma. In previous investigations, we reported that loss of heterozygosity at the Rb gene locus, telomerase activity, hTERT, and c-Myc expression were associated with tumor progression in liposarcomas. In this study, we report on a case of a WD/DDL, in which both tumor components were separated using laser microdissection (P.A.L.M.) for the investigation of hTERT mRNA expression on a LightCycler. Macroscopically selected and histologically proven cryosections of low malignant and highly malignant tumor areas were cytogenetically investigated to confirm the diagnosis and to find additional chromosomal alterations with tumor progression.     

Malignant fibrous histiocytoma of bone and osteosarcoma. A comparative light and electron microscopic study.

Malignant fibrous histiocytomas are well-described tumors of the soft tissues. Recent investigations have shown that malignant histiocytoma may also occur as a primary bone tumor. However, difficulties may arise to distinguish malignant histiocytoma of bone from other malignant bone tumors, such as osteosarcoma. In the present study, the ultrastructure of five cases of malignant fibrous histiocytoma of bone is compared with that of osteosarcoma. The results show that malignant fibrous histiocytoma is composed mainly of histiocytic cells and fibroblastic cells. In addition, xanthomatous cells, undifferentiated cells, and giant cells may be observed. By contrast, the predominant cell type in osteosarcoma is the neoplastic osteoblast, characterized by abundant rough endoplasmic reticulum. Signs of matrix calcification in the intercellular matrix between the collagen fibrils are regularly observed in osteosarcoma, but not in malignant histiocytoma. From these results it is concluded that the ultrastructure of malignant fibrous histiocytoma arising in bone is morphologically identical with the soft tissue counterpart of this tumor. The components of the tumor are derived from neoplastic histiocytes. This cytogenesis differs from that of osteosarcoma, which is derived from neoplastic osteoblasts. Therefore, from the ultrastructural point of view, malignant fibrous histiocytoma of bone should be accepted as a distinct histologic entity among bone tumors.     

Recurrent dedifferentiated liposarcoma of the spermatic cord simulating malignant fibrous histiocytoma: an immunohistochemical and ultrastructural study

A case of recurrent dedifferentiated liposarcoma simulating malignant fibrous histiocytoma, with complete absence of lipoblastic differentiation, is described. The tumour cells showed strongly positive immunostaining for alpha-1-antichymotrypsin. Electron microscopy revealed a mixture of fibroblasts and histiocytes. Our findings suggest that the dedifferentiated component reflects an altered differentiation pathway of the primitive mesenchymal cells in the original liposarcoma.     

Malignant fibrous histiocytoma arising in a recurrent chordoma

Summary We present the case of a sacrococcygeal chordoma which recurred 15 years after the radical removal as a soft tissue tumor in the gluteal musculature. This tumor consisted of two parts: a chordoma without symptoms of aggressive cellular proliferation and a malignant fibrous histiocytoma. During the following 4 years several local recurrences of the malignant fibrous histiocytoma occurred in the gluteal musculature. The patient finally died of lung metastases. No chordoma tumor tissue was found in the lungs, in the gluteal musculature or in the sacrococcygeal bone area. Histology including electron microscopy revealed no proof of a transition of chordoma into malignant fibrous histiocytoma. It must be assumed that the secondary soft tissue tumor originated from residual chordoma cells which were implanted during the operation of the primary tumor. It remains unclear whether the malignant fibrous histiocytoma arose from mesenchymal stromal cells within the chordoma or directly from primitive neuroectodermal chorda cells which possess the ability to differentiate into a variety of cell types including mesenchymal cells.     

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.     

Acute Myopathy Associated with Chronic Licorice Ingestion: Reversible Loss of Myoadenylate Deaminase Activity

A case of recurrent soft part sarcoma with focal areas showing epithelial differentiation in the right thigh in a 78-year-old woman is reported. The primary tumor consisted of myxoid areas and solid areas, in which relatively uniform epithelioid tumor cells were arranged in sheets, whereas pleomor-phism and a storiform pattern appeared in the recurrent tumors. Thus this tumor was suspected to be a malignant fibrous histiocytoma. However, further studies showed unexpected ultrastructural and immunohistochemical features. Cytokeratin immu-noreactivity and tonofilamentlike structures probably indicated epithelial differentiation of some tumor cells. From the clinical and histological findings, this tumor should be identified as a malignant fibrous histiocytoma with phenotypic expressions of epithelial cell.     

Malignant Fibrous Histiocytoma with Epithelial Differentiation?

A case of recurrent soft part sarcoma with focal areas showing epithelial differentiation in the right thigh in a 78-year-old woman is reported. The primary tumor consisted of myxoid areas and solid areas, in which relatively uniform epithelioid tumor cells were arranged in sheets, whereas pleomor-phism and a storiform pattern appeared in the recurrent tumors. Thus this tumor was suspected to be a malignant fibrous histiocytoma. However, further studies showed unexpected ultrastructural and immunohistochemical features. Cytokeratin immu-noreactivity and tonofilamentlike structures probably indicated epithelial differentiation of some tumor cells. From the clinical and histological findings, this tumor should be identified as a malignant fibrous histiocytoma with phenotypic expressions of epithelial cell.     

Giant cell malignant fibrous histiocytoma of the breast: a case report

A case of primary malignant fibrous histiocytoma of the breast is reported. The patient was a 48-yr-old woman with a huge tumor involving almost the entire left breast. The central portion of her left breast was already rotted by extensive necrosis and inflammation. She was treated by radical mastectomy and axillary lymphadenectomy to level I. Pathologic examination supported by an immunohistochemical staining confirmed the tumor as malignant fibrous histiocytoma of giant cell type. Axillary lymph nodes were free from tumor metastasis. She had not taken any postoperative adjuvant therapy. The metastasis to lungs was found 2 months after the operation, and she died within 6 months.     

Liposarcoma. A clinicopathologic subtyping of 52 cases

Fifty-two cases of liposarcoma were analyzed clinicopathologically, and were grouped into the following five types: myxoid (28 cases), well-differentiated (14 cases), pleomorphic (4 cases), round-cell (3 cases), and mixed (3 cases). Three of the 28 myxoid tumors showed a pleomorphic pattern resembling that of the myxoid variant of malignant fibrous histiocytoma, and one of the 3 round-cell tumors was considered to be a malignant counterpart of hibernoma. Ages ranged from 22 to 86 years with the average age of 49 years, the average patients with myxoid or round-cell liposarcoma being over 10 years younger than those with well-differentiated or pleomorphic liposarcoma. There was also a variation in the site of predilection of the cases: the great majority of myxoid type tumors occurred in the thigh, popliteal fossa and buttock (23 cases), while the majority of well-differentiated type tumors were seen in the retroperitoneum (10 cases). The rate of local recurrence of the tumor was 46%. Four of the 5 well-differentiated liposarcomas which recurred exhibited dedifferentiated pleomorphic components resembling those in malignant fibrous histiocytoma. The prognosis was more favorable in patients with ordinary myxoid tumors than in those with well-differentiated tumors. The overall relative five-year survival rate was 63%.     

LIPOSARCOMA

Fifty-two cases of liposarcoma were analyzed clinicopathologically, and were grouped into the following five types: myxoid (28 cases), well-differentiated (14 cases), pleomorphic (4 cases), round-cell (3 cases), and mixed (3 cases). Three of the 28 myxoid tumors showed a pleomorphic pattern resembling that of the myxoid variant of malignant fibrous histiocytoma, and one of the 3 round-cell tumors was considered to be a malignant counterpart of hibernoma. Ages ranged from 22 to 86 years with the average age of 49 years, the average patients with myxoid or round-cell liposarcoma being over 10 years younger than those with well-differentiated or pleomorphic liposarcoma. There was also a variation in the site of predilection of the cases: the great majority of myxoid type tumors occurred in the thigh, popliteal fossa and buttock (23 cases), while the majority of well-differentiated type tumors were seen in the retroperitoneum (10 cases). The rate of local recurrence of the tumor was 46%. Four of the 5 well-differentiated liposarcomas which recurred exhibited dedifferentiated pleomorphic components resembling those in malignant fibrous histiocytoma. The prognosis was more favorable in patients with ordinary myxoid tumors than in those with well-differentiated tumors. The overall relative five-year survival rate was 63%.     

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.     

Angiomatoid malignant fibrous histiocytoma

Summary A case of an angiomatoid malignant fibrous histiocytoma is presented. The electron microscopic findings demonstrate the presence of a variety of tumor cell types including smooth and striated muscle cells. This indicates that malignant fibrous histiocytoma originates from a pluripotent primitive mesenchymal cell.     

Aspiration cytology of lipomatous tumors: A 10-year experience at an orthopedic oncology center

The cytodiagnoses of preoperative fine-needle aspirate smears from 72 histologically proven lipomatous tumors (52 lipomas and 20 liposarcomas of varying type) collected during the 10-yr period 1972–1981 were correlated to the corresponding histopathologic diagnoses. Three out of 52 lipomas were erroneously diagnosed as low-grade malignant liposarcomas, and one out of 20 liposarcomas was falsely diagnosed as a benign soft-tissue tumor. Of the 20 liposarcomas, 15 were cytologically diagnosed as such, and the majority of the myxoid and the pleomorphic liposarcomas were correctly diagnosed as to type. Important differential diagnostic problems were, on one hand, the separation of lipoma with regressive changes and histiocytic reaction and lipoma with chondroid metaplasia from low-grade malignant liposarcoma and, on the other hand, liposarcoma from intramuscular myxoma, myxofibrosarcoma, and malignant fibrous histiocytoma. The differential diagnosis of liposarcoma as opposed to other soft-tissue sarcomas is discussed, and it is concluded that preoperative fine-needle aspiration of lipomatous tumors is of value in the management of these tumors. Diagn Cytopathol 1987;3:295–302.     

Disseminated malignant fibrous histiocytoma (giant cell rich): a case report

Giant cell rich malignant fibrous histiocytoma accounts for 3 -15% of all malignant fibrous histiocytomas. Currently, the nomenclature giant cell malignant fibrous histiocytoma is reserved for undifferentiated pleomorphic sarcomas with prominent osteoclastic giant cells. It is considered to be synonymous with malignant giant cell tumor of soft parts. We report a case of disseminated giant cell malignant fibrous histiocytoma involving the scalp, cervical node, lungs, spine, abdominal wall, base of penis, gluteal cleft, paraspinal region and back. The diagnosis was established after staining for a panel of immunohistochemical markers namely cytokeratin, vimentin, S100, desmin, CD68 and smooth muscle actin. CD68 positivity in tumor cells helped in arriving at the final diagnosis. It is essential to recognize this tumor as a giant cell rich distinct entity and differentiate from other giant cell rich pleomorphic sarcomas since therapeutic and prognostic differences are being appreciated currently.     

Malignant fibrous histiocytoma of the retroperitoneal space and left shoulder]

Mixed malignant fibrous histiocytoma is described. The peculiarity of the case is the primary tumor location in the left shoulder soft tissues and retroperitoneal space with the growth into the superior mesenteric artery, total necrosis of the small bowel and the ascending part of the colon.     

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.     

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.     

Reticular angiomatoid "malignant" fibrous histiocytoma--a case report with cytogenetics and molecular genetic analyses

Angiomatoid "malignant" fibrous histiocytoma is a rare sarcoma of low malignant potential that occurs most commonly in the extremities of children and young adults. Herein, we present a case of angiomatoid malignant fibrous histiocytoma with unusual histologic features arising in the mediastinum of an 80-year-old man. The tumor exhibited a reticular growth pattern and myxoid stroma. The tumor cells expressed epithelial membrane antigen and desmin. Cytogenetic analysis revealed the translocation t(2;22)(q33;q12). Molecular genetic analysis confirmed the rearrangement of the EWSR1 locus and the presence of the EWSR1/CREB1 fusion. This report expands the clinicopathologic spectrum of angiomatoid malignant fibrous histiocytoma and underscores the value of integrating morphologic, immunophenotypic, and molecular findings in the identification of its unusual morphologic variants.