Background: Despite the variety of epithelial malignancies seen in the breast, primary squamous cell carcinoma (SCC) of the breast is rare. It was often classified as one of the metaplastic carcinomas of the breast, although it can arise denovo from benign cysts in the breast. The reported incidence is less than 0.1% of all the ductal carcinomata. It has no distinct clinical features and radiological appearances are also unremarkable.

Case report: We managed a 43-year-old housewife at the General Surgery Unit of University of Maiduguri Teaching Hospital Borno State-Nigeria, who presented with an 11-month old left breast lump that developed malignant features 2 months prior to presentation. A diagnostic Ultra Sound Scan revealed a 10cm retroareola cystic mass with irregular margins and no colour flow on Doppler interrogation, with a provisional diagnosis of a chronic breast abscess. A Fine Needle Aspiration Cytology was equivocal. A wide local excision with axillary dissection was done and postoperative histopathologic analysis showed a primary squamous cell carcinoma. The resection margins were free and only one lymph node showed metastatic deposit.

Conclusion: Adenocarcinoma of the breast is the most common malignancy in the breast. The absence of primary squamous cells in the breast renders pure squamous cell carcinoma a rarity. The presentation of squamous cell carcinoma could be similar to that of an adenocarcinoma or bears a benign outlook. It is imperative therefore to subject all benign lesions of the breast to pathological analysis after removal.