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We evaluated the clinicopathological spectrum of intrathoracic rhabdoid carcinoma, including its immunophenotype and ultrastructural features. Our series included 6 cases arising from the lung (4 cases) and the anterior mediastinum (2 cases). The patients were 4 men and 1 woman aged between 40 and 63 years (median, 53 years). Microscopically, all of the lesions were composed of loosely cohesive, large, atypical polygonal cells, with glassy cytoplasms and eccentric nuclei. Chromatin texture was finely granular or open. On immunohistochemical stain, the neoplastic cells were positive for vimentin in all cases, positive for vimentin, keratins and/or epithelial membrane antigen in all cases, and negative for other antigens. In 1 case, neoplastic cells were also positive for CD34. Electron microscopic study showed prominent perinuclear whorls of densely packed intermediate filaments or mitochondria. All patients were treated with combined chemotherapy and radiotherapy. One patient died 8 months after the diagnosis was made. Of the remaining patients, 3 are alive with evidence of disease progression, including brain metastases. We concluded that rhabdoid neoplasms arising in the thoracic cavity are aggressive tumors of epithelial lineage and should be categorized as true “rhabdoid carcinomas” instead of being ambiguously designated as “intrathoracic rhabdoid tumors” or “carcinomas with rhabdoid phenotype.”

We report on nine new cases of myxoinflammatory fibroblastic sarcoma; in six of them the location of the tumor was distal (acral), and proximal in three (forearm, arm, and thigh). Tumors varied in size from 1.5 to 18 cm, were well-circumscribed, yellow-tan, and focally myxomatous. Histologically, they were similar in appearance and showed vaguely lobular architecture and oval, spindle, and epithelioid neoplastic cells with scattered, focally aggregated inflammatory cells. In all cases, in different numbers, bizarre giant cells with large, lobulated, or multiple nuclei were also admixed, some of them morphologically imitating Reed-Sternberg cells, lipoblasts, or ganglion cells; they showed distinct nucleoli or intranuclear inclusions. Myxoid areas were always present, to different extent. Immunohistochemically, tumor cells were uniformly positive for vimentin; some cells were also positive for CD68 and CD34. Ultrastructurally, tumor cells were nondescript, consistent with fibroblastic origin. On flow cytometry, two of the examined cases showed diploid pattern with low S-phase fraction. In none of the cases, metastases were observed, in one case the tumor recurred 5 years following surgery. We conclude that myxoinflammatory fibroblastic sarcoma is a distinct soft tissue tumor of low-grade malignancy and, until now, described only in extremities, although not confined to acral sites. Ann Diagn Pathol 6:272-280, 2002.

Osteogenic melanoma may mimic many other tumors, especially osteogenic sarcoma; only 12 cases have been reported so far. To characterize this unusual neoplasm further, we present the clinicopathologic findings of a new case. A 67-year-old woman was treated unsuccessfully for “fungal granuloma” of her great toe. After nail ablation and incisional biopsy, the toe was exarticulated. Histologically, we found a high-grade, spindle, focally epithelioid, amelanotic malignant tumor with a distinct osteoid and chondroid matrix. Spindle, epithelioid, osteoblastic, and chondroblastic tumor cells were immunoreactive for vimentin, S-100 protein, and NKI/C3. Ultrastructurally, diagnostic premelanosomes were not identified. Features that support a diagnosis of osteogenic melanoma are superficial subungual location, absence of bone involvement, and immunoreactivity for vimentin, S-100 protein, and NKI/C3. The unusual features of current tumor are absence of radial growth phase, negative reaction to HMB-45, and ultrastructural absence of melanosomes.

A case of inflammatory pseudotumor of the urinary bladder in a 2-year-old child is presented. It was characterized by nodular intravesical growth and massive infiltration of the bladder wall. Microscopically, the lesion showed in its largest part a relatively paucicellular spindle cell growth and a sclerotic appearance with a thin superficial cellular zone resembling granulation tissue. Another morphological characteristic was a marked capillary proliferation revealed by immunohistochemical reactions to factor VIII-associated protein, laminin, and collagen IV. The last feature appears to be an integral part of the process, which most closely resembled fibromatosis of the adult type, a rare pattern of growth in inflammatory pseudotumor.

A case of epithelioid hemangioendothelioma of the anterior mediastinum in a 40-year-old woman is presented. It showed typical features described in such tumors, but in addition there were foci of osteoclast-like giant cells that were not previously reported in this lesion.

Soft tissue sarcomas of the breast account for less than 1% of all malignant breast tumors. The majority of these lesions have an epithelial component and are thus classified as "cystosarcoma phyllodes." All other types of sarcomas are categorized according to the existing histological soft tissue classification. It is difficult to determine the relative frequency of the different types of breast sarcoma because there are wide variations among the reported series. We report a case of myxofibrosarcoma, a variant of malignant fibrous histiocytoma, in a 58-year-old woman.