A rare case of non-invasive ductal carcinoma of the breast coexisting with follicular lymphoma: A case report with a review of the literature

The double presentation of breast cancer and follicular lymphoma is extremely rare, and only six cases have previously been reported in the literature. In the present study, a case of synchronous ductal carcinoma in situ (DCIS) of the breast and follicular lymphoma is reported. During an annual breast screening procedure, a 49-year-old female presented with a hard induration under the nipple of the right breast and swelling of a soft lymph node (LN) in the right axilla. Mammography and ultrasonography revealed two lesions in the right breast: One was a tumor with microcalcification, 1.0 cm in diameter, and the other was a large, crude calcification, 2.5 cm in diameter. In addition, computed tomography and positron emission tomography revealed swellings of the bilateral axillary (Ax) LN and intra-abdominal para-aortic LN. The patient underwent excisions of the large calcified mass, a micro-calcified tumor and the right AxLN. The pathological and immunohistochemical studies revealed fat necrosis and DCIS of the breast, which was positive for the estrogen receptor and the progesterone receptor, while human epidermal growth factor receptor II protein expression was evaluated as 2+ and stage was classified as pTis pN0 M0, stage 0. Furthermore, the Ax node was diagnosed as follicular lymphoma, which was positive for cluster of differentiation (CD)20, CD79a, CD10 and B-cell lymphoma (Bcl)-2 protein, but negative for Bcl-6 protein. The clinical stage was classified as stage III. The patient was administered chemotherapy followed by radiotherapy to the conserved breast. Two years have passed since the surgery, and the patient is disease-free.