PRIMARY OSTEOGENIC-SARCOMA OF THE BREAST - A CLINICOPATHOLOGICAL ANALYSIS OF 50 CASES

Extraskeletal osteosarcomas are rare. Few primary mammary osteosarcoma s have been reported; many of these have been described in association with a biphasic tumor. Fifty pure osteosarcomas of the breast, diagno sed between 1957 and 1995, were reviewed after excluding those of biph asic origin. The absence of epithelial differentiation was confirmed u sing a panel of immunohistochemical markers in 32 cases and using ultr astructural evaluation in an additional four cases. Tumors occurred in 49 women and one man; age ranged from 27 to 89 years (median, 64.5 ye ars). One patient received radiotherapy for ipsilateral breast carcino ma 9 years before presentation. Patients were treated by excisional bi opsy (n = 13), tylectomy (n = 5) or mastectomy (n = 32). All axillary nodes, dissected in 20 patients, were free of tumor. One patient had e xtramammary spread at diagnosis. The neoplasms were 1.4 cm to 13.0 cm (mean, 4.6 cm), and 60% were grossly circumscribed. Tumors were classi fied as fibroblastic (n = 28), osteoclastic (n = 14), or osteoblastic (n = 8). Of 39 patients with available follow-up information, locally recurrent(n = 11)and metastatic (n = 15) disease developed in 23 (59%) at a mean of 10.5 and 14.5 months from diagnosis. Eight (73%) patient s in whom local recurrence developed were treated with excisional biop sy or tylectomy; of these, seven had a positive margin. Sixteen (41%) patients died of disease at a mean of 17.1 months, within 20 months of onset of metastases, most commonly to the lung. Mammary osteosarcomas are aggressive tumors with a propensity for blood-borne rather than l ymphatic spread. Total excision without axillary dissection is advised .