Solitary fibrous tumor of the upper respiratory tract. A report of six cases.

We report six cases of a neoplasm that arose in the upper respiratory tract and had a histological appearance indistinguishable from that of solitary fibrous tumor of the pleura (SFT, so-called fibrous mesothelioma). The patients were adults who presented with nasal obstruction. The lesions lacked the characteristic features of other recognized neoplasms that occur in this region. The tumor cells were immunoreactive for vimentin but not for keratin. The occurrence of SFT in this location further supports the argument that SFT is a tumor of mesenchymal and not mesothelial origin. None of the tumors in this series had the histologic features of malignancy described for SFT in other locations, and there was no aggressive behavior in limited follow-up. Until more cases of SFT in unusual locations have been studied, we recommend that the same criteria used for assessing aggressiveness in SFT of the pleura be applied to them.

Solitary fibrous tumor of the mediastinum. A report of 14 cases.

Fourteen cases of a mediastinal neoplasm identical to solitary fibrous tumor (so-called fibrous mesothelioma) of the pleura were observed. The lesions presented with cough, chest pain, dyspnea, or as asymptomatic masses detected radiographically. Two patients had associated hypoglycemia. Eleven of the tumors were in the antero-superior mediastinum. One arose on a pedicle from the thymus, and another had entrapped thymic elements. Tumor cells were variably immunoreactive for vimentin and actin, but not for keratin, and lacked ultrastructural evidence of mesothelial or epithelial differentiation. Eight cases had highly cellular mitotically active regions of which six of seven with follow-up behaved aggressively; the exception was the pedunculated tumor. A 13-cm, histologically bland tumor has recurred twice. Aggressive behavior was more common than reported for solitary fibrous tumor of the pleura, but the same criteria (size, cellularity, mitotic activity, presence of pedicle) were of prognostic significance. The occurrence of solitary fibrous tumor in the mediastinum with the suggestion of thymic origin for some cases, combined with the immunohistochemical and ultrastructural findings, support a mesenchymal origin for this tumor. The differential diagnosis includes spindle cell thymoma, hemangiopericytoma, and peripheral nerve tumors.

A biphasic tumor of the mediastinum with features of synovial sarcoma. A report of four cases.

Four cases of a biphasic mediastinal tumor histologically identical to synovial sarcoma of soft tissue were observed. The tumors presented as solitary mediastinal masses. Although the tumors were frequently adherent to adjacent pleura or pericardium, none appeared to be arising from a mesothelial surface. All cases were composed of an intimate admixture of keratin-positive epithelial cells and vimentin-positive spindle cells with areas of transition, hyalinization, and calcification. Follow-up was available on three patients, who died of their disease 10 months, 14 months, and 4 years after diagnosis, respectively. Although synovial sarcoma usually occurs in deep soft tissues near joints in the extremities, it has been reported in locations removed from synovial, tendon sheath, and bursal structures. This report adds a previously unrecognized location for synovial sarcoma, the mediastinum. Occurrence in this location further supports an origin from pluripotential mesenchyme as opposed to synovium. The differential diagnosis includes mesothelioma, thymoma, germ cell tumors, malignant peripheral nerve sheath tumor with glandular differentiation, and metastatic carcinoma.

Osteogenic sarcoma and soft tissue myxoma in a patient with fibrous dysplasia and hemoglobins JBaltimore and S.

A 41-year-old man with recognized polyostotic fibrous dysplasia since late childhood developed fibroblastic osteogenic sarcoma in the left tibia. Four months after the initial diagnosis, an intramuscular myxoma was discovered in the left thigh. Twenty years previously he had been found to be heterozygous for hemoglobins JBaltimore and S. Malignant transformation in fibrous dysplasia is unusual and may be associated in some individuals with prior irradiation. Soft tissue myxomas associated with fibrous dysplasia are even rarer. To the best of the authors' knowledge the occurrence of both of these lesions in a patient with fibrous dysplasia has been reported only once before. Patients with both fibrous dysplasia and myxomas may be at greater risk for malignant transformation than are individuals with only one of these lesions. There is no well-recognized association between hemoglobinopathies and either fibrous dysplasia or bone tumors. It is therefore probable that the rare constellation of findings is in this patient a stochastic event.

Angiosarcoma of the uterus: a light microscopic, immunohistochemical, and ultrastructural study.

A 71-year-old woman who presented with severe vaginal bleeding was found to have a uterine angiosarcoma after total abdominal hysterectomy and bilateral salpingo-oophorectomy. The diagnosis was confirmed by immunohistochemical studies that showed positive staining of tumor cells for factor VIII-related antigen and by ultrastructural studies revealing vasoformative structures surrounded by a thin basal lamina. Primary vascular tumors of the uterus are rare. The existence of malignant vascular neoplasms of the uterus has been questioned, and at most nine previously reported cases have been generally accepted as valid examples of uterine angiosarcoma. Based on those cases, the prognosis of uterine angiosarcoma is poor. Our studies demonstrate that angiosarcoma does occur in the uterus. Our patient is presently alive with recurrent disease.