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MALIGNANT PHYLLODES TUMOR WITH THREE DIFFERENT SARCOMATOUS COMPONENTS – A CASE REPORT

INTRODUCTION: Malignant phyllodes tumor of the breast is a rare biphasic neoplasm. Its stroma shows frankly sarcomatous, usually fibrosarcomatous changes. Heterologous differentiation such as liposarcoma, osteosarcoma, chondrosarcoma or rabdomyosarcoma may occur. CASE REPORT: A 71year-old woman was admitted because of a painless lump in her right breast. Physical examination revealed a movable mass, about 3 cm in diameter, in the upper outer quadrant of the right breast. The patient underwent ultrasonography and mammography showing a 3.5 cm oval and relatively well circumscribed mass with coarse, amorphous calcifications (Fig. 1). Right breast 20x16x4.5 cm and axilla 9x7x3 cm were admitted for histopathological examination. In the upper outer quadrant a whitish-gray, hard mass with infiltrative borders that measured 3.3 cm in maximum diameter was found. Microscopically, the tumor was consisted of three different sarcomatous components. The most prevalent was made of osteoid surrounded by proliferating atypical osteoblasts and multinucleated, osteoclast-like giant cells. Focally, trabeculae of woven bone with coarse calcifications surrounded with atypical osteoblasts were also noted (Fig. 2). Second sarcomatous component contained lipoblasts, atypical mesenchymal cells with high mitotic activity, and mature lipomatous cells (Fig. 3). In some areas the tumor was composed of round to oval atypical cells with scanty, poorly outlined cytoplasm in the chondromatous matrix with partially myxoid changes (Fig. 4). The entire tumor was sampled for histology to find its epithelial component. In few additional samples epithelial component was found which consisted of luminal epithelial and myoepithelial cells surrounded with hypercellular, mitotically active stroma that showed enhanced intracanalicular growth pattern with leaf-like projections into dilated lumens (Fig 5). Immunohistochemical analysis (CK, EMA, SMA, desmin, S-100) confirmed existence of three different sarcomatous components. Nine lymph nodes measuring from 1 to 5 cm were found in axillary fat tissue and were without signs of the tumor. The diagnosis of malignant phyllodes tumor with associated osteosarcomatous, chondrosarcomatous and liposarcomatous differentiation was established. DISSCUSION: To our knowledge this is the second report in English literature of malignant phyllodes tumor with associated different sarcomatous components. The first case of a 96-year-old female patient with malignant phyllodes tumor, which stroma contained elements of leiomyosarcoma, liposarcoma, rhabdomyosarcoma and malignant fibrous histiocytoma, was reported by Guerrero et al. Due to overgrowth of the sarcomatous components malignant phyllodes tumor may be confused with pure sarcomas of the breast or with carcinosarcomas. In our case, because of three-associated sarcomatous components the main differential diagnosis was carcinosarcoma. After surgical excision, careful gross examination and thorough sampling of the specimen is recommended to establish definitive diagnosis. In our case, evidence of malignant epithelial component was not found and the diagnosis of malignant phyllodes tumor with associated osteosarcomatous, chondrosarcomatous and liposarcomatous stromal differentiation was established.

malignant phyllodes tumor; sarcomatous component

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