A breast sarcoma containing rhabdomyosarcomatous and other metaplastic elements

Benign Smooth Muscle Cell Metaplasia in Breast

Three different benign breast lesions showing smooth muscle cells in the stroma are reported. Benign smooth muscle cells are rarely found in the breast, and it is likely that they originate from metaplastic changes of the stroma itself.

Primary and metastatic rhabdomyosarcoma in the breast: neoplasms of adolescent females, a report from the Intergroup Rhabdomyosarcoma Study

The occurrence of rhabdomyosarcoma (RMS) primary in or metastatic to breast has been regarded as an uncommon event, associated with an unfavorable outcome. Records of 26 patients with diagnoses of breast RMS, either primary or secondary, entered in the Intergroup Rhabdomyosarcoma Study (IRS) (1972-1992) were reviewed and compared with data regarding 47 similar patients in published reports. Of the 26 IRS cases, the histologic subtype was alveolar in 24, embryonal in 1, and not determined in 1. All were female with ages ranging from 11.5 to 20.2 years (median, 15.2 years; mode, 14-16 years). This compact age distribution of both primary (n = 7) and metastatic (n = 19) breast RMS was seen in previously reported series. Among the 19 cases of RMS with initial dissemination to breast, primary tumor sites, were extremity (n = 8), nasopharynx/paranasal sinuses (n = 7), and trunk (n = 4). IRS treatment was risk-based according to site and extent of disease. Four of 7 patients with primary RMS remain disease free 2.9 to 7 years post diagnosis. Among 19 patients with RMS initially metastatic to breast, including 7 in IRS clinical group IV at original diagnosis, three are disease free at 7.6, 15.7 and 17.0 years.

CONCLUSIONS

primary or metastatic RMS in breast is almost confined to adolescent females having tumors with alveolar histology. Approximately one-half of the patients with primary breast disease and 15% of those with metastatic breast disease as an initial recurrence are long-term survivors.

Mammary carcinosarcoma presenting as rhabdomyosarcoma: an ultrastructural and immunocytochemical study

A mass in the left breast of a 32-year-old woman was first diagnosed as sarcoma with rhabdomyosarcomatous differentiation. Subsequent studies demonstrated a malignant epithelial component to be present, changing the diagnosis to carcinosarcoma. This course of events supports the concept that many, if not all, sarcomas of the breast would be mixed tumors with a malignant epithelial component, if search for the epithelial component was extensive. Carcinosarcomas with rhabdomyosarcomatous differentiation in the breast are rare, but like sarcomas elsewhere, they do not metastasize to regional lymph nodes, but disseminate hematogenously, primarily to the lungs.

Carcinoma of the breast with pseudosarcomatous metaplasia

Twenty-six cases of breast carcinoma demonstrating pseudosarcomatous metaplasia are described, and their clinical and pathologic aspects are correlated. The metaplastic elements include mature and immature bone, cartilage, myxoid stroma, loose fibromyxoid and dense spindle-cell stroma, and anaplastic stroma with giant cell features. Light and electron microscopic examination demonstrated an orderly sequence of transformation and dedifferentiation of epithelial cells to become undifferentiated mesenchymal cells. These tumors are more aggressive than purely epithelial carcinomas. The overall survival rate was 44%. Five-year survival figures for TNM Stages I, II, and III lesions were 56%, 26%, and 18%, respectively. The incidence of lymph node metastasis was 25% despite the large size of many of these tumors. Systemic metastases replicated the range of metaplastic elements seen in the primary site. Patients with tumors composed predominantly of pseudosarcomatous elements had worse prognoses than those with predominantly epithelial components (28% versus 62%, 5-year survival).