Primary squamous cell carcinoma (SqCC) of the breast.

Primary squamous cell carcinoma (SqCC) of the breast is a rare tumor that presents a unique biologic behavior. Thus, it challenges the justification for routine axillary dissection and adjuvant therapy. A MEDLINE search of all reported cases of primary SqCC of the breast was performed. Data on lymph node status, estrogen receptor (ER) and progesterone receptor (PR) status, and surgical and adjuvant treatment modalities were collected. We add three cases from our own experience. SqCC has several unique biologic characteristics; it is associated with a lower rate of lymph node metastasis at presentation (22% vs. 40-60% for infiltrating ductal carcinoma [IDC]) and a significant rate of distant metastasis without lymph node involvement. ER and PR receptor levels are usually very low. Because lymph node involvement plays a lesser prognostic and therapeutic role in this disease, we propose a more selective approach (i.e., sentinel node biopsy). The issue of adjuvant treatment remains unresolved, owing to lack of data. Surgical and medical treatment of SqCC of the breast should be tailored to fit its distinct biologic characteristics. The 5-fluorouracil-doxorubicin-cisplatin combination may be warranted in lieu of the combinations used for IDC.