Mantle cell lymphoma in lymph nodes with metastatic small cell carcinoma of lung: a diagnostic and treatment dilemma.

We report a rare case of small cell carcinoma (SCC) of lung, metastatic to ipsilateral hilar and peribronchial lymph nodes with synchronous mantle cell lymphoma (MCL), in a 58-year-old female. She was treated with Cisplatin, Etoposide, and Rituximab, and remained in complete remission for approximately two and a half years following the initial diagnosis. To the best of our knowledge, synchronous SCC and MCL or SCC metastatic to lymph nodes involved by MCL has not been previously reported. In this case, the features of MCL were very inconspicuous in the lymph nodes with extensive metastases of SCC. The presence of MCL was confirmed by immunohistochemistry and fluorescence in situ hybridization (FISH). The co-existence of lymphoma and metastatic carcinoma in the same lymph node, as seen in this case, highlights the significance of analyzing subtle lymphoid architectural changes, and applying ancillary studies such as immunohistochemistry and molecular analysis in suspicious cases. The management of synchronous SCC and MCL requires consideration of their respective biologic behavior, and cumulative toxicity of treatment regimens of both tumors. In such cases an optimum treatment strategy should be adopted to cover both malignancies with minimal toxic effect.