Fumiaki Masui

Evaluation of new monoclonal anti-MyoD1 and anti-myogenin antibodies for the diagnosis of rhabdomyosarcoma.

New monoclonal anti‐MyoD1 and anti‐myogenin antibodies were evaluated immunohistochemically to determine whether they are useful in discriminating rhabdomyosarcoma (RMS) from other soft tissue tumors in routinely processed sections. Neither MyoD1 nor myogenin was expressed in normal, mature striated muscle. In RMS, nuclear expression of MyoD1 and myogenin was found in 82 and 80% of non‐overlapping cases, respectively. MyoD1 was generally expressed in small, primitive tumor cells, and larger cells exhibiting morphological evidence of skeletal muscle differentiation failed to express positive nuclear immunostaining. Positive nuclear staining for myogenin was stronger than that for MyoD1 in cases with abundant differentiated tumor cells, but was less prominent in cases in which small, primitive tumor cells predominated. No leiomyosarcomas, Ewing’s sarcomas/peripheral primitive neuroectodermal tumors or other soft tissue tumors exhibited nuclear expression of MyoD1 or myogenin. In conclusion, both anti‐MyoD1 and anti‐myogenin antibodies are useful for diagnosing RMS and for discriminating RMS from other soft tissue tumors.

Giant cell tumor of bone: A clinicopathologic study of prognostic factors

Forty‐seven cases of giant cell tumor of bone were clini‐copathologically reviewed to determine any useful prognostic factors. Disease recurred In 11 cases. Eight of these cases had initially been treated with lntracapsular piecemeal excision and three cases had been treated with wide excision. Nine of the 11 cases were classified as Grade III, two cases as Grade II, and one case as Grade II + fracture according to Campanaccis radiographic grading system. lntracapsularly excised cases had a high recurrence rate (47.1%). Metastasis to the lung occurred in three cases, each of which had been classified as Grade III. Although the radiographic Grade did not correlate wlth the rate of lung metastasis or recurrence, cases that metastasized to the lung or recurred tended to be radiographically aggressive. Disease recurred in eight of 24 Grade III cases; but in only two of 12 Grade II cases, in one of five Grade II + fracture cases, and none of six Grade I cases. p53 Was expressed by mononuclear stromal cells in SIX cases. Disease recurred In four and lung metastasis occurred In three of these cases. p53 Expression correlated wlth rates of lung metastasis and recurrence. R was concluded that cases in which p53 is expressed have a high potential for lung metastasis and recurrence.

Giant cell tumor of bone: An immunohistochemical comparative study

Forty‐seven cases of giant cell tumor (GCT) of bone were reviewed pathologically to elucidate the origin of spindle‐shaped stromal cells or the hlstogenesls of mononuclear histiocytic stromal cells and osteoclast‐like giant cells (OCGC). To clarify the histogenesis of OCGC, eight cases of sarcoma associated with OCGC were reviewed for a comparative study. Spindle‐shaped stromal cells sometimes produced minute foci of osteoid matrix. Proliferating cell nuclear antigen (PCNA) was observed In spindle‐shaped stromal cells and mononuclear histlocytic stromal cells, but not in OCGC. Matrix metalloprotelnase (MMP)‐9 was expressed by mononuclear histiocytic stromal cells and OCGC, and its expression was correlated with the lung metastasis rate. In both GCT and sarcomas with OCGC, mononuclear histiocytic stromal cells and OCGC expressed CD68, parathyroid hormone‐like protein (PTH‐LP), MMP‐1 and MMP‐9. Immunoreactivity of mononuclear histiocytic stromal cells and OCGC to CD68, PTH‐LP, MMP‐1 and MMP‐9 was similar between GCT and sarcomas with OCGC. These observations may suggest that mononuclear histiocytic stromal cells and OCGC are reactively Induced with several cytokines acting in an autocrine or paracrine fashion and that these cells are closely related with the biologic aggressiveness of GCT.

A MALIGNANT PERIPHERAL NERVE-SHEATH TUMOUR RESPONDING TO CHEMOTHERAPY

A malignant peripheral nerve-sheath tumour developed in the right S1 nerve root in a man aged 30 causing back pain and sciatica. CT and MRI revealed a destructive tumour of the sacrum invading the retroperitoneal space. The tumour was not resectable with an adequate margin. Chemotherapy, consisting of high-dose ifosfamide followed by a combination of vincristine, doxorubicin and cyclophosphamide, was given with success. Malignant peripheral nerve-sheath tumours are thought to respond weakly to chemotherapy, but the response in our patient was complete.

Dumbbell-shaped osteochondroma of the fifth rib causing spinal cord compression

Osteochondromas are the most common benign bone tumor, representing 45% of all benign bone tumors. Most occur in the metaphyseal region of long bones such as the femur and tibia. Osteochondromas can also arise from fl at bones and the spine. Costal osteochondromas make up only 1.5% of all osteochondromas, and compressive myelopathy due to a tumor arising from the rib is even rarer. We present an unusual case of a dumbbell-shaped osteochondroma causing spinal cord compression, and we review the literature concerning costal osteochondromas.

Osteosarcoma of the metatarsal bone

Abstract A case of osteosarcoma arising from a metatarsal bone is reported, focusing on the radiological findings and differential diagnosis.