Synchronous occurrence of breast cancer and refractory diffuse large B-cell abdominal lymphoma: Management and review of the literature.

The synchronous occurrence of primary breast cancer and lymphoid tissue malignant tumors has been rarely reported in the literature. We present an exceedingly rare case of synchronous breast invasive ductal carcinoma with an abdominal diffuse large B-cell lymphoma (DLBCL). A 78-year-old woman who was diagnosed with a luminal A invasive breast cancer on core biopsy, and complaint of progressively worsening low back pain. An abdominal computed tomography (CT) scan that was performed as part of the preoperative staging showed a large abdominal mass measuring 10.5 × 4.8 × 9.5 cm surrounding the lower part of the abdominal aorta, the right common iliac, right external, right internal iliac, and the left internal iliac arteries. A CT-guided fine-needle aspiration biopsy (FNAB) of the abdominal mass was then performed, to exclude the possibility of being an abdominal tumor metastasis of the known primary breast cancer. Histopathological findings were suggestive of DLBCL. Following a multidisciplinary team discussion, chemotherapy was initiated for DLBCL. The tumor however was refractory to multiple chemotherapy regimens and exhibited a highly aggressive clinical course. The diagnostic evaluation and management of the patient are discussed, along with a review of the relevant literature. This case underscores the fact that the presence of synchronous malignancies may pose both diagnostic and treatment challenges. Accurate staging of both malignancies and multidisciplinary team discussion is of utmost importance to guide an optimal therapeutic approach. Histopathological evaluation is essential for both tumors, for the second malignancy not to be misinterpreted as a secondary deposit of the primary one.