RESUMO
INTRODUCTION: Breast Cancer with osteoclast-like stromal giant cells (OLGCs) is a rare pattern of invasive non-special type ductal carcinoma. The OLGCs are specific type of macrophage and are likely distinct from true osteoclasts. The aim of this case series was to describe the characteristics of this invasive ductal carcinoma rare histotype. PRESENTATION OF CASES: The authors present the cases of two young women that, during national screening, discovered with mammography X-ray a breast lump suspected for malignancy. The core needle biopsy confirmed the malignancy of both nodule and in one patient the histological analysis revealed pre-operative OLGCs. In both cases the sentinel lymph node biopsy was negative therefore a quadrantectomy without axillary lymphadenectomy was done. The definitive histopathological examination was positive for invasive ductal carcinoma with OLGCs and CD 68 marker positivity. After surgery, patients underwent adjuvant therapy and multidisciplinary follow-up. DISCUSSION: The origin and mechanism for developing osteoclast-like giant cells is unknown. The OLGCs directly descend from the precursors of the monocyte-macrophage. The rarity of this entity often promotes a misleading diagnosis, with >50 % of erroneous diagnosis of benign lesion. The prognostic significance of OLGCs in breast cancer is controversial, however it doesn't seem to influence the axillary lymph nodes spread. The presence of preoperative OLGCs didn't modify our surgical and oncological approach. CONCLUSION: Breast Cancer with OLGCs is a rare tumour that has a similar prognosis to other carcinomas of identical grade and stage in most cases. The rarity and characteristics of this neoplasm require personalized treatments, discussed by a multidisciplinary team.