Primary squamous cell carcinoma of the breast: A cytological and histological correlation

Primary squamous cell carcinoma of the breast (PSCCB) is an extremely rare disease. Origin is controversial; it is thought to arise through the metaplasia of various benign and malignant breast lesions. It usually present with rapidly growing large mass, otherwise similar to that of ductal breast carcinoma. Fine needle aspiration cytology (FNAC) is an accurate and safe diagnostic procedure for breast malignancies. However, cytologists are still facing some difficulties in specific diagnosis of various subtypes of breast malignancy. Extensive squamous cells on cytology should be evaluated with the great caution. Ductal breast carcinoma with squamous metaplasia, squamous carcinoma of the breast skin, and metastasis from non-mammary tissues should be consider before the making the diagnosis of PSCCB. Specific management and prognosis of PSCCB is still debatable. We present a case of 52-year-old woman with a breast mass. FNAC revealed predominantly clusters and dispersed malignant squamous cells, without any ductal cells, suggest PSCCB; possibility of secondary or ductal breast carcinoma with squamous metaplasia should be ruled out. After modified radical mastectomy histology confirmed the diagnosis of PSCCB. Post-operative cisplatin and 5-fluouracil were administered. Patient is disease free at 12 months of follow-up.