Metaplastic Squamous Cell Carcinoma - A Very Rare Entity of Breast Carcinoma in an Elderly Female Patient

Metaplastic squamous cell carcinoma of breast is a rare malignancy and accounts to < 1% of all breast cancers and it is most commonly seen in elderly women. As the tumor cells exhibit heterogeneous behavior, a standard therapeutic approach is difficult to establish. Age, size of the tumor, lymph node metastasis and receptor status are the important prognostic factors. Metaplastic squamous cell carcinoma has very unfavorable prognosis compared to other triple negative breast malignancies. Surgery combined with neoadjuvant radiotherapy can ameliorate the disease outcome. Early diagnosis and treatment play a crucial role in the management. Here we report a case of metaplastic squamous cell carcinoma of breast in a 67 years female who came with breast lump in the left breast for 6 months with palpable axillary lymph nodes. She underwent modified radical mastectomy with the diagnosis of Ductal cell carcinoma reported on fine needle aspiration cytology. Lymph node clearance done at all levels and the specimen was sent for histopathological examination. Gross examination revealed unifocal gray white irregular tumor measuring 9 x 4 x 3.6 cms located in the inner central quadrant and container labelled as level 1 revealed 7x 4 x 3 cms firm mass. Microscopic examination revealed infiltrating tumor tissue in nesting pattern, syncytial pattern and solid pattern. The tumor cells were having pleomorphic nuclei, increased N:C ratio and moderate to scant eosinophilic cytoplasm. Within the nesting pattern of tumor tissue keratin pearls were seen. Interstitium showed lymphocytic infiltration. One lymph node from level 1 showed metastatic deposits. The tumor was diagnosed as metaplastic Squamous cell carcinoma of left breast with TNM staging of PT3 N1 Mx. Keywords: Squamous, metaplastic, breast, poor prognosis.