Primary right breast diffuselarge B cell lymphoma coexistingwith left breastinvasive ductal carcinoma

A 69-year-old woman was referred to the surgical oncology service after presenting the initial complaint of a palpable mass in her right and left breast discovered on breast self-examination. A core biopsy of right and left breast was performed. Immunohistochemistry was performed with ER, PR, Ki-67, E-cadherin, Her2/neu, CKAE1/AE3, LCA,
CD3, CD5, CD10, CD20, CD21, CD23, CD79α, bcl-2, bcl-6 and cyclin-D1 staining. The targeted next gene sequencing (NGS) of the both tumour tissue was performed. Right breast tumours composed of diffuse proliferation of large to medium sized centroblasts like cells with irregular nuclear contours, large nucleoli and scant cytoplasm suggest
ing malignant lymphoma. They were positive for LCA and CD20, but negative for cytokeratin, CD3, CD5 and CD10 as wells as estrogen or progesterone receptors.
Left breast tumour was Grade II invasive ductal carcinoma not otherwise-specified (IDC). ER, PR-positive (90 %), Her-2/neu-negative and E-cadherin was positive, Ki-67 index-was 25 %.
The NGS analysis showed that both DLBCL and IDC had showed similar MYC, GATA3, STAT3, CCND1, CCND2, mTOR and JAK-1 mutations.
To conclude, our study demonstrated a very rare case of primary breast diffuse large B cell lymphoma in one breast co-existing with invasive ductal carcinoma in the other breast. The specific genetic mutations could contribute to the pathogenesis of these synchronous tumours.