[Unusual case of benign neoplasm of the breast mimicking a carcinoma: granular cell tumor. Case report].

Granular cell tumors are rare, usually benign neoplasms of soft tissues which most commonly occur in the tongue, skin and subcutaneous tissue. Although the histogenesis is still object of debate, recent immunohistochemical studies and ultrastructural findings support the origin of this neoplasm from the peripheral nervous tissue, most likely from Schwann's cells. Occurrence of this neoplasm in the breast, although uncommon, warrants special attention, since its clinical, mammographic and pathological appearances on frozen sections "may often closely resemble" hose of breast malignancy. The authors analyze and commenton, with special reference to clinical aspects and surgical treatment, a case of benign granular cell tumor of the breast occurring in a 42 year-old woman. The mammographic and clinical findings suggested a breast carcinoma. The correct diagnosis was established by definitive microscopic examination of the paraffin-embedded specimens and the treatment was a simple local excision of the tumour and a small rim of surrounding breast parenchyma. Although the granular cell tumor of the breast is a rare entity, surgeons and pathologists should be aware of its existence in order to avoid inappropriate radical surgery not justified by the benign behavior of the neoplasm.