Shinichiro Ushigome

PERINEURIAL CELL TUMOR AND THE SIGNIFICANCE OF THE PERINEURIAL CELLS IN NEUROFIBROMA

The authors attempted to clarify the exact cell components of neurofibroma by immunohistochemical and ultrastructural studies. Materials were randomly selected, 40 cases of neurilemoma and neurofibroma (‐tosis) in addition to 2 cases of tumors composed exclusively of perineurial cells and three cases of normal peripheral nerve. The applied markers included antisera of S‐100 protein for Schwann cells, blood coagulation factor XIIIa for endoneurial fibroblasts or perineurial cells, and laminin and collagen type IV for the basement membrane. S‐100 protein was demonstrated only in normal or neoplastic Schwann cells, but not in perineurial cells. On the other hand, factor XIIIa was often recognized in endoneurial fibroblasts and perineurial cells, but not in Schwann cells. Neurofibroma was basically composed of a mixture of Schwann cells, perineurial cells, and endoneurial fibroblasts, the population of each type of cell differing according to the case and area within a given tumor. Perineurial cell tumor exclusively composed of perineurial cells, though rare, appears to be a definite entity, and its characteristic histological and ultrastructural features were described.

ULTRASTUCTURE OF CARTILAGINOUS TUMORS AND S‐100 PROTEIN IN THE TUMORS: With Reference to the Histogenesis of Chondroblastoma, Chondromyxoid Fibroma and Mesenchymal Chondrosarcoma

Twelve cartilaginous tumors were studied by electron microscopy and the presence of S‐100 protein was studied immunohistochemically in order to clarify the cell origin of chondroblastoma, chondromyxoid fibroma, and mesenchymal chondrosarcoma. Three chondroblastomas were characterized by round or ovoid tumor cells with some cytoplasmic processes, well‐developed organelles and thick fibrous laminae in the nuclear membrane, occasional multinucleated giant cells and scanty chondroid matrix. S‐100 protein was demonstrated in the tumor cells and some multinucleated giant cells. Two chondromyxoid fibromas revealed tumor cells of varied shapes with character istic cartilaginous differentiation and abundant chondroid matrix. Spindle tumor cells showed the ultrastructural features of cartilage cells rather than of fibroblasts and S‐100 protein was also demontratrated in their cytoplasm. Chondroblastoma and chondomyxoid fibroma were considered to arise from chondrocytes. Mesenchymal chondrosarcoma ultrastructurally exhibited round tumor cells with cartilaginous nature in cartilage islands. Poorly‐differentiated portions were composed of primitive round or elongated cells with occasionally admixed round cells with ultrastructural features of cartilaginous differentiation. S‐100 protein was demonstrated in the cells in cartilage islands and in single cells admixed in poorly‐differentiated portions. These results support the hypothesis of primitve mesenchymal origin with a tendency to differentiate toward cartilage cells. ACTA PATHOL. JPN. 34: 1285–1300, 1984.

PROLIFERATIVE MYOSITIS AND FASCIITIS: Report of Five Cases with an Ultrastructural and Immunohistochemical Study

Cases of proliferative myositis and fasciitis were studied immunohisto‐chemically and ultra structurally for further understanding of the nature of ganglion cell‐like giant cells. Blood coagulation factor XIIIa, fibronectin, myoglobin, myosin, CPK MM, and alpha‐1‐antichymotrypsin were detected in three cases of proliferative myositis and two cases of proliferative fasciitis by the avid in‐biotin‐peroxidase complex method. Factor XIIIa (a fibrin‐stabilizing factor) and flbronectin were strongly positive in the giant cells, but not in striated muscle fibers. A small quantity of myosin was demonstrated in the giant cells, but myoglobin and CPK MM were never demonstrated in these cells. No alpha‐1‐antichymotrypsin was demonstrated in the giant cells. One case of proliferative myositis showed ultrastructural features suggestive of fibroblast rather than muscle cell or histiocytic origin. Strongly positive factor XIIIa in the giant cells is suggestive of the fact that they are active fibroblasts.

Case report 482

Fig. 1. A plain film of the right foot shows a partially calcified, destructive, and expanding lesion involving the distal, middle, and proximal phalanges of the right second toe. A slightly expansile lesion of the head of the right first metatarsal also is observed. The cortices of the affected bone also are extremely attenuated and have mostly disappeared in the lesions of the distal and middle phalanges

Case report 263

A 13-year-old girl was admitted to the St. Marianna University Hospital on 26 February 1981 because of a gradually increasing focal swelling in the lower segment of the left thoracic cage, together with a history of pain in that region over a seven-month period. Radiological studies on admission showed a destructive, expanding lesion of the left 10th rib, associated with a large soft tissue mass. A thin outer bony shell of the 10th rib was apparent (Fig. 1).

Malignant Fibrous Histiocytoma

The histological diagnosis of malignant fibrous histiocytoma (MFH) seems to have become recently fashionable among pathologists, although its histo‐genesis and diagnostic criteria are not entirely settled as yet. For practical purposes the differential diagnosis with other easily mistakable mesenchymal tumors should be strictly made with great caution, because of variable histological features of this tumor. The authors attempted to elucidate the differential points from other tumors in a review of 189 cases of malignant soft tissue tumors. Some cases of carcinoma mimicking MFH were also reviewed. No single criterion for making the histological diagnosis of MFH was obtained. Its histological features and differential points from pleomorphic rhabdomyosarcoma and fibrosarcoma were tabulated.

CHONDROMYXOID FIBROMA OF BONE

A resected case of chondromyxoid fibroma of the right fibula in a 31‐year‐old male is presented. The histology was composed of characteristic lobular features of this tumor with abundant cartilaginous matrix. The ultrastructural study exhibited stellate, ovoid or elongated tumor cells with features of cartilage cells and abundant loose matrix with many fine filamentous structures. The nuclei were often of peculiarly indented contour and revealed thick fibrous lamina. The villous cell processes and intracytoplasmic fine filaments were prominent. No cells suggesting a fibroblast were recognized in this study. From the light microscopical and ultrastructural findings of this case, it is supported that this tumor might be derived from adult cartilage cells most likely related to the epiphyseal cartilage rather than fibroblasts.

JUVENILE GRANULOSA CELL TUMOR ASSOCIATED WITH RAPID DISTANT METASTASES

We have encountered a case of juvenile granulosa cell tumor, first described by SCULLY as a specific form of granulosa cell tumor, in a 23‐year‐old, nul‐liparous female associated with some unusual clinicopathological features. The tumor showed a diffuse or macrofollicular pattern with eosinophilic or clear, often vacuolated cytoplasm containing abundant lipid. Ultrastructures revealed features very similar to those of previously reported juvenile granulosa cell tumor. Intracytoplasmic filaments were observed, but smooth surfaced endoplasmic reticulums were not evident. The patient succumbed unexpectedly rapidly due to recurrence and distant metastasis, in spite of anti‐cancer therapy. It is also interesting that suprisingly high levels of estrogens as well as testosterone in both urine and serum was recorded before surgery and after the development of recurrence.