Pure primary breast squamous cell carcinoma.

Pure and primary breast squamous cell carcinoma is a very rare entity, with a prevalence rate of less than 0.1% of all breast carcinomas. Its diagnosis has strict histologic and clinical diagnosis criteria, in order to exclude ductal breast carcinoma with squamous differentiation, squamous carcinoma originated from the breast skin and metastasis from non-mammary tissues. Described as an aggressive disease, often treatment-refractory, it has a significantly worse prognosis than other nonsquamous cell tumours of the breast. The authors present a case report of a women diagnosed in our institution with breast pure primary squamous cell carcinoma and review the literature for diagnosis criteria, morphological features, histogenesis, prognosis, and therapy.