Clinical history: A 69 year old female with history of right breast cancer presents with new mass in her right breast
What is your diagnosis?
Discussion and answers
Diagnosis: Invasive ductal carcinoma, metaplastic type [squamous differentiation].
The invasive tumor in this case shows extensive squamous differentiation, including keratinisation. The DCIS shows areas of more usual high grade DCIS but there are areas suggestive of squamous differentiation also present. Immunohistochemistry was done and showed p63 strong nuclear positivity in the vast majority of the invasive carcinoma. CK 5/6 (not shwon) is also strongly positive for the vast majority of cells in the invasive tumor, Cd117 (not shown) is negative and EGFR shows membrane positivity in about 50% of the cells. The tumour is positive for HER-2/neu overexpression and negative for ER/PR.