Primary Lung Adenocarcinoma as a Second Neoplasm Following Chronic Lymphocytic Leukemia: A Case Report.

Chronic lymphocytic leukemia (CLL) and its variant, small lymphocytic lymphoma (SLL), are common adult leukemias characterized by the accumulation of mature monoclonal B lymphocytes. CLL primarily involves peripheral blood, spleen, and lymph nodes, whereas SLL predominantly affects lymph nodes. Patients with CLL/SLL are at increased risk of developing second primary malignancies, including lung cancer, highlighting the need for ongoing surveillance. We report the case of an 83-year-old man with a history of CLL/SLL who developed pulmonary adenocarcinoma. He presented weight loss and constitutional symptoms; imaging revealed retroperitoneal and mesenteric lymph node conglomerates along with a lung lesion. Histopathology confirmed SLL in the lymph nodes and primary mucinous adenocarcinoma of the lung. Evidence shows a heightened risk of second primary neoplasms in CLL/SLL, particularly among patients exposed to alkylating agents. This case emphasizes the role of demographic and treatment-related factors-such as male sex, advanced age, smoking history, and therapeutic regimens-in secondary cancer development. Vigilant monitoring and a multidisciplinary approach tailored to individual risk are essential for early detection and optimal management in this population.