Sansen Yoh

Malignant fibrous histiocytoma. A tumor of facultative histiocytes showing mesenchymal differentiation in cultured cell lines.

The histogenesis of malignant fibrous histiocytoma (MFH) is controversial. To elucidate the cellular origin and characteristics of this neoplasm, the authors analyzed cell lines grown from 17 patients (15 soft tissue MFH and 2 bone MFH) by using light and electron microscopy, immunocytochemistry, enzyme cytochemistry, and functional tests for receptors for the Fc portion of immunoglobulin (Fc receptors) and immunophagocytosis. Each culture exhibited a storiform/pleomorphic pattern with mixed cellular populations consisting of spindle cells, polygonal cells, and bizarre giant cells; these morphologic features corresponded to the histologio characteristics of the primary tumors. The cells in each MFH line displayed histiocytic functional markers such as lysosomal enzymes, Fc receptors, and immunophagocytosis. However, these cells differed from monocyte‐derived macrophages (histiocytes) in immunoreactivity; the MFH cells expressed a mesenchymal antigen (FU3) distributed among perivascular cells and fibroblasts but demonstrated no positive reactions with Leu‐M1 (CD15) and Leu‐M3 (CD14), which recognize the cells of the monocyte‐macrophage lineage. In conclusion, these findings suggest that MFH is not a tumor of true histiocytes but of facultative histiocytes showing mesenchymal differentiation in vitro. Chromosomal analysis performed in one MFH line demonstrated abnormal karyotypes; the modal chromosome number was 58, with 5 marker chromosomes.

Malignant fibrous histiocytoma. Proliferative compartment and heterogeneity of "histiocytic" cells.

To elucidate the precise origin and characteristics of the proliferating cells in malignant fibrous histiocytoma (MFH), the authors analyzed 33 MFH tumors, using immunohistochemical techniques with a panel of 12 antibodies. All three types of MFH cells (spindle cells, polygonal cells, and bizarre giant cells) stained positively for mesenchymal antigens (FU3 and vimentin) but did not stain for macrophage/histiocyte markers (HAM 56 and CD68). Therefore, the MFH cells may not represent true histiocytes, although they may be mesenchymal-derived cells behaving as “facultative histiocytes” with superficial resemblance to actual histiocytes. Normal histiocytes in the stroma tested positive for macrophage/histiocyte antigens; the most common cells were HAM 56-positive cells constituting 30-80% of nonneoplastic stromal cells, followed by those positive for CD68 (10-50%), Mac 387 (<2%), and S-100 protein (<1%). Our results indicate the presence of heterogeneity of “histiocytic” cells in MFH. Proliferating-cell nuclear antigen (PCNA) was expressed not only in the spindle and polygonal MFH cells but also in the bizarre giant cells. These findings suggest that all three types of MFH cells participate in the proliferative compartment of MFH. Uneven PCNA staining of the irregular nuclear segments of the bizarre giant cells may result in abnormal DNA synthesis, possibly contributing to the marked diversity of nuclear morphology in MFH. Touton- type and osteoclast-like giant cells did not stain for PCNA but stained positively for histiocytic markers. Therefore, these giant cells may lack proliferative activity and probably result from normal histiocytes fusing together.

Epithelioid sarcoma with an 18q aberration.

Epithelioid sarcoma is a peculiar soft-tissue neoplasm of uncertain origin, which is characterized by an epithelioid morphology of tumor cells coexpressing epithelial (keratin) and nonepithelial (vimentin) antigens. We herein report a new cytogenetic abnormality with der(22)t(18;22)(q11;p11.2) in a case of epithelioid sarcoma that occurred in the elbow of a 75-year-old man. Histologically, the tumor demonstrated a multinodular proliferation of epithelioid cells, with positive immunostaining for keratin, epithelial membrane antigen (EMA), and vimentin. Cultured tumor cells obtained from fresh surgical materials were frozen in plastic ampules and stocked in a liquid nitrogen freezer. Six years after surgery, the cells were recovered from the freezer and utilized for both morphologic and cytogenetic analyses. These cultured cells both before and after the freezing exhibited essentially the same epithelioid morphology and immunophenotypes as those of the original tumor. A chromosome analysis, together with fluorescence in situ hybridization (FISH), demonstrated a 61-67 modal population, and a characteristic clonal abnormality with der(22)t(18;22)(q11;p11.2). Other clonal abnormalities included numerical (-3, -4, +7, -13, -14, -16, -18, +20, -22) and structural (8p+, 9p+, 12p+, i(21q)) aberrations. Some variant clones also demonstrated i(18q). Since the breakpoint at 18q11 is similar to that reported in synovial sarcoma, this finding may support the presence of a histogenetic relationship between epithelioid sarcoma and synovial sarcoma. Our study thus indicates that the storage of frozen cells is useful for both morphologic and cytogenetic analyses of soft tissue tumors.

Juvenile Aponeurotic Fibroma: An Ultrastructural Study

The light and electron microscopic findings in a case of juvenile aponeurotic fibroma are described. The tumor was composed of fibromatosislike areas and cartilagelike islands with characteristic calcification. The ultrastructural study verified the cartilaginous nature of this tumor. The cartilagelike islands were made up of chondrocytic cells embedded in an abundant intercellular matrix containing fine fibrils, spherical granules, and pleomorphic membrane-bound vesicles. The chondrocytic cells had many microvilli, a well-developed granular endoplasmic reticulum, and a prominent Golgi complex. In the periphery of each cartilagelike island was a perichondriumlike structure exhibiting transitional features from fibroblastic cells to chondrocytic cells. The fibromatosislike areas consisted of spindle-shaped fibroblastic cells and occasional myofibroblasts. The morphologic pattern of the tumor somewhat mimics embryonal chondrogenesis, and the fibromatosislike areas may represent an overgrowth of the fibrous layer of the perichondrium. It is possible to regard this tumor as an organoid tumor having a capacity for bidirectional differentiation into cartilage and fibrous tissue.

Surgical management of a large Schwannoma

Magnetic resonance imaging is useful fr diagnosing bone and soft tissue tumors. We report a patient with a schwannoma which gradually grew into a huge mass over a 12 year period. The deagnosis was possible using CT imaging, MRI, amgiogrephy, scintigraphy, and biospy. We recommend that MRI (especially, Gd-enhanced MRI) is useful for detecting the solid area of a huge systic mass for biopsy.

Malignant fibrous histiocytoma in the thoracic region —A clinico-pathologic investigation

Seven cases of malignant fibrous histiocytoma (MFH); 3 originating in the thoracic region, one which was considered to arise from the lung parenchyma, and 4 which were metastatic to the lungs, are presented herein. Six of these patients underwent surgical excision and analysis under light and electron microscopy revealed the lesions of MFH to be composed of two cell types; a fibroblast-like cell and a histiocyte-like cell. The latter showed histologically characteristic growth in a so-called storiform pattern. In all patients adjuvant chemotherapy was performed, although in only one patient did it prove temporarily effective. Despite the fact that the prognosis of MFH in the thoracic region is poor, the suggested therapy for longer survival is resection with postoperative combination chemotherapy including the use of sensitive anticancerous agents.

Conservative treatment for complete dislocation of the acromioclavicular joint by plaster spica. - Second report.

In this report, the conservative treatment for the complete dislocation of acromioclavicular joint by plaster spica is discussed.Sixteen patients were treated, 15 being men and one woman. The average age was 32 years (range, 19-43). We applied plaster spica with 90 degrees arm abduction to immobilize the scapula and reduce the distal end of the displaced clavicle using elastic band. Thus managed, the articular surface of the acromioclavicular joint contacts each other closely. The alignment of reduced acromioclavicular joint must be confirmed by X-ray for 4 to 6 weeks. 13 cases completed treatment in this manner but 3 cases gave up treatment halfway owing to severe pain or failure of reduction. Follow-up periods averaged 1 year and 7 months.Pain relief was generaly satisfactory but anatomical reduction was obtained in only 6 of the 13 completed cases. The relations between reduction and the shape of the acromioclavicular joint were discussed in this series according to Urists classification. 8 of the 13 cases were type II (Vertical) or type V (Incongruent & No contact) and the other 5 were type I (Overriding) or type IV (Incongruent & Overriding). 6 cases which gained anatomical reduction in this series were all classified into type II and type V.Anatomical reduction seemed to be important for the improvement of function and the relief of symptoms. The results were not so good in older patients because of residual contracture.