Intracranial Low-Grade Fibromyxoid Sarcoma: Findings on Electron Microscopy and Histologic Analysis.

BACKGROUND: Low-grade fibromyxoid sarcoma is a rare tumor that manifests as a deep soft tissue mass characterized by a benign histology, but with potentially aggressive clinical behavior and a high rate of recurrence; primary intracranial sarcomas are even rarer. We present a case of primary intracranial low-grade fibromyxoid sarcoma, emphasizing its clinical, radiologic, and histologic features. CASE DESCRIPTION: A 39-year-old woman presented with a recent history of headache and seizures. A right parietal mass was detected on computed tomography and magnetic resonance imaging, and she was subsequently operated on to remove the intracranial mass. Histologic examination of the resected tumor revealed mildly atypical fibroblastic cells embedded within a myxoid matrix. The diagnosis was confirmed by electron microscopy and cytogenetic analyses. CONCLUSIONS: This report describes electron microscopic evaluation of intracranial low-grade fibromyxoid sarcoma, which has an extremely rare occurrence.

Myxosarcoma of the right ventricle: an immunohistochemical and ultrastructural study.

BACKGROUND: Myxosarcoma is an unusual form of primary cardiac malignancy with few reports in the literature. Although these tumours occur in a similar anatomical distribution to cardiac myxoma, the relationship between these two tumours is uncertain due largely to the limited studies available that characterise the morphological features of myxosarcoma. MATERIALS AND METHODS: The clinical and pathological features, including immunohistochemical and ultrastructural studies of cardiac myxosarcoma, in a 58-year-old male who died eight months after onset of symptoms are reported. RESULTS: At presentation the tumour was sited in the right ventricle and at post-mortem was found to have extended into the right atrium, pulmonary infundibulum, pulmonary artery, pericardium and pleural cavities. Histologically the tumour was composed of spindle and stellate cells within a myxoid stroma. Ultrastructural studies showed abundant intermediate filaments and vacuoles within the tumour cell cytoplasm, without any evidence of muscle differentiation. Immunohistochemical staining for vimentin and myoglobin was positive, while there was negative expression of desmin, smooth muscle actin, factor VIIIa, CD34, CD68, S-100 protein, bcl-2 and for epithelial markers. CONCLUSION: Comparison of the morphological findings from the present case with the limited data available suggests that myxosarcoma is not a single tumour entity but a group of tumours of diverse histogenesis.

Myxofibrosarcoma. Clinicopathologic analysis of 75 cases with emphasis on the low-grade variant.

Myxofibrosarcoma is one of the most common sarcomas in the extremities of elderly patients. We analysed the clinicopathologic features in a series of 75 patients. All patients were adults (range, 22-91 years; median, 66 years) with an approximately equal incidence in men and women. Thirty-five tumors arose in the lower and 25 in the upper extremities, nine on the trunk, two each in the retroperitoneum and the head and neck region, and one each in the pelvis and penis. Forty-eight cases (69.5%) were located in dermal or subcutaneous tissues. Distinctive histologic features included the following: a commonly nodular growth pattern; a myxoid matrix containing elongated, curvilinear capillaries; and fusiform, round or stellate tumor cells with indistinct cell margins, slightly eosinophilic cytoplasm, and hyperchromatic atypical nuclei. These lesions varied from a hypocellular, mainly myxoid, and purely spindle-cell appearance (low-grade neoplasms) to high-grade, pleomorphic (malignant fibrous histiocytoma-like) lesions with multinucleated giant cells, high mitotic activity, and areas of necrosis. Immunohistochemistry in 44 cases revealed only vimentin and occasional actin positivity. Ultrastructurally, tumor cells had a fibroblastic phenotype. DNA flow cytometry and proliferation analysis showed an association between aneuploidy and histologic grade. An average follow-up of 45 months (range, 5-300 months) in 60 cases has revealed local recurrence in 33 cases (54%). Thirteen patients developed metastases, and 13 tumor-related deaths occurred. A short interval to first local recurrence was associated with poor clinical outcome. The rate of local recurrence was independent of histologic grade, but only intermediate and high-grade neoplasms metastasized. The depth of the primary lesion did not influence the incidence of local recurrence. However, in deep-seated neoplasms, the incidence of metastases was higher and the percentage of tumor-related deaths was twice as high as in superficially located lesions, reflecting the fact that deep-seated lesions tended to be higher-grade, larger tumors. Myxofibrosarcoma tends to become progressively higher grade in recurrences, as demonstrated in five cases in our series. The poorly recognized low-grade myxofibrosarcoma is emphasized, as proper diagnosis and treatment and scrupulous follow-up are mandatory to avoid local recurrence and gradual tumor progression to a higher-grade neoplasm that may then metastasize.

Myxosarcoma in a Sinaloan milksnake.

A 2-year-old Sinaloan milksnake was examined because of a 1-cm mass attached to the lateral wall of the coelom. A diagnosis of myxosarcoma was made on the basis of histologic features and special staining characteristics.

[Clinical, pathological and electron microscopic observation of cardiac myxoma of the right atrium].

Five cases of cardiac myxoma of the right atrium and 1 case of myxosarcoma which involved both left and right atria are reported. Clinical manifestations were palpitation, shortness of breath, systolic and diastolic murmurs at the apical or tricuspid area, etc. Evidence of right atrial enlargement was shown on X-ray film. Echocardiographic examination was highly valuable in the diagnosis of this disease. The morphology of the myxoma of the right atrium was similar to that of the left one. The former was larger and heavier than the latter. Hemorrhage and necrosis inside the tumors were usually more severe in right atrial myxoma than the left. The clinical and pathological features (gross, histological and ultrastructural) are briefly discussed. In this series, 1 case of right atrial myxoma was complicated by alveolar cell carcinoma, but the histological changes of the two tumors were totally different.

Myxoid sarcoma arising from the pulmonary trunk.

We reported a case of a myxoid sarcoma of the pulmonary trunk in a 40-year-old women. On light and immunohistochemical studies, spindle-shaped tumor cells revealed the nature of smooth muscle origin.

Primary malignant tumor of the heart.

An autopsy case of a primary malignant tumor of the heart in a 15-year-old boy was reported. The tumor had possibly arisen from the subendocardial region of the septal area of right atrium, occupied the atrial septum and formed a spherical mass with a diameter of ca. 9 cm. It protruded into the right atrial chamber and ruptured the endocardium. Multiple metastases were observed in the lungs and the paratracheal lymph nodes. On the basis of light and electron microscopic features, the tumor was interpreted as a poorly differentiated mesenchymal tumor with partial myxosarcomatous differentiation. The histogenetical aspects of this tumor were discussed with reference to morphology and cytodifferentiation of primitive mesenchymal tissues of the heart.

Ultrastructure of mesodermal mixed tumor of the uterus.

A case of mesodermal mixed tumor arising in the uterus of a 57-year-old woman is presented. The tumor was a mixture of adenocarcinoma with occasional squamous metaplasia, stromal sarcoma, myxosarcoma and chondrosarcoma. Light and electron microscopic examinations of the tumor revealed close transition between stromal sarcomatous component and each of other sarcomatous and carcinomatous component. The histogenesis of mixed mesodermal tumor was discussed and it was concluded that the tumor might be derived from endometrial stromal cell which possessed the pluripotency to differentiate toward various epithelial and mesenchymal tissues including the heterologous mesenchymal tissue.

[Brain metastases from primary cardiac myxosarcoma--report of a case (author's transl)].

A very rare case of a myxosarcoma with metastases to the brain is reported. A 33-year-old female was admitted to our hospital because of lassitude, fever, slight left hemiparesis, headache and other signs of intracranial hypertension and cardiac symptoms such as dyspnea and palpitation. She had the cardiac symptoms once 14 years before, which reappeared and rapidly aggravated two months before the admission. Cerebral angiography revealed a mass in the right temporal lobe and physical and laboratory examinations revealed mitral value failure and hyperthyroidism. On the next day, March 19, 1976, a grossly cystic 60 gm tumor was totally removed which was largely imbedded in the subcortex of the right temporal lobe. The symptoms except for the cardiac symptoms and disseminated intravascular coagulopathy rapidly improved, but headache and left hemiparesis returned 13 days postoperatively. She died suddenly 18 days after the operation due to acute cardiac failure. Autopsy revealed two separate hard and solid tumors both attached to the mitral valve and occupied the whole left atrium and another metastasis to the frontal lobe which had not been diagnosed before the death. Microscopic examinations including electronmicroscopic study established the diagnosis of myxosarcoma in all the four tumors.