Telangiectatic osteosarcomatous differentiation in a phyllodes tumour

High grade phyllodes tumor with osteosarcomatous differentiation: Case report and review of the literature

Phyllodes tumors (PTs) are rare fibroepithelial malignancies of the breast, accounting for less than 1% of malignant breast tumors. PTs are usually solitary tumors but can be associated with other malignancies, such as DCIS or invasive carcinomas and sarcomas. Osteosarcomatous differentiation of a malignant phyllodes tumor is rare, and differentiation of this rare breast tumor from other entities is of vital importance to clinicians due for appropriate treatment and prognosis. We present a case of rare high-grade phyllodes tumor with osteosarcomatous differentiation presenting on mammogram as a calcified lobulated mass; ultrasound revealed a 1.5 cm irregularly calcified mass, suggestive of bone. An ultrasound-guided core biopsy and subsequent lumpectomy revealed a cellular stroma with osteoid stromal matrix and cytologic atypia with bone formation. At 18 months postprocedure, a recurrence was identified at the previous surgical site, and the patient underwent a mastectomy. Here we present a single case of high-grade PT with osteosarcomatous differentiation and a comprehensive literature review, highlighting the mammographic and histologic characteristics of this rare presentation.

Phyllodes Tumor with Osteosarcomatous Differentiation: A Comparative Immunohistochemical Study between Epithelial and Mesenchymal Cells

Aims and background

Phyllodes tumor of the breast with osteosarcomatous differentiation is rare and very little is known about its molecular profile.

Methods and study design

An immunohistochemical panel with 37 primary antibodies including cytokeratins, mesenchymal markers, key regulators of the cell cycle, oncogenes, apoptosis-related proteins, metalloproteinases and their inhibitors was performed on a formalin-fixed paraffin-embedded sample of phyllodes tumor with osteosarcomatous differentiation in a 49-year-old woman.

Results

Antiapoptotic stimuli (survivin) predominated in sarcomatous cells. Antiproteolytic stimuli (TIMP-1, TIMP-2 and PAI) were preponderant in all cells, a surprising fact in view of the aggressiveness of the neoplasm. The immunoprofile of the osteoblastic and stromal cells was quite similar, except for c-erbB-3, c-myc, cyclin D1 and p21. Both exhibited positive cells for actin, MyoD1 and GFAP.

Conclusions

Our results suggest that this osteosarcoma may have originated from metaplasia of stromal cells that underwent a malignant change.