Abstract
INTRODUCTION: Squamous carcinoma is a very rare breast cancer resulting from a differentiated squamous metaplasia. Its diagnosis is late due to the absence of specific clinical and radiological features. PRESENTATION OF CASE: The authors present the case of a 39-year-old patient with the clinical onset of an inflammatory cyst diagnosed with mammography and cytological examination. After segmentectomy, on histological examination was defined as: "squamous keratinizing aspect". In light of this report she was subjected to quadrantectomy with lymphadenectomy. She did not undergo radiotherapy treatment, which was delayed due to the ongoing pandemic. After a few months developed a local recurrence and underwent a mastectomy with multidisciplinary treatment. DISCUSSION: Squamously-differentiated metaplastic carcinoma of the breast is one of the rarest forms of breast cancer. Its etiopathogenesis is still unclear but some authors suggest that it originates from a squamous metaplasia deriving from the epithelium of cysts. This is a very aggressive and fast-growing tumour especially in young women, in fact the patient had a recurrence after a few months. She came to our attention 6 months after the initial surgery with a relapse at a local-regional level for which she was subjected to radical treatment and with a metastatic spread for which she was given the first-line chemotherapy treatment. CONCLUSION: There are no well-defined guidelines for the treatment of this rare form of cancer. The case illustrates how the rapid aggressiveness of the disease requires adequate and immediate multidisciplinary treatment from the very beginning.