What happened, in summary

This 83-year-old man had type 2 diabetes and a history of chronic lymphocytic leukemia/small lymphocytic lymphoma, or CLL/SLL, diagnosed 6 years earlier. He had previously received bendamustine and rituximab and was under follow-up. At a routine visit, he reported weight loss, weakness, and fatigue, and blood tests showed leukocytosis, monocytosis, anemia, and elevated LDH, raising concern for CLL/SLL relapse. Abdominal CT showed a large retroperitoneal and mesenteric lymph-node conglomerate. Chest CT also found a spiculated 2.5 × 1.9 cm nodule in the posterior basal segment of the right lower lung, plus bilateral hilar lymphadenopathy. Biopsy of the abdominal lymph nodes confirmed SLL, with CD20, PAX5, BCL2, CD5, and CD23 positivity and Ki-67 of 20%. Thoracoscopic wedge resection of the lung lesion showed a separate primary mucinous lung adenocarcinoma with enteric differentiation. The lung tumor expressed TTF-1, CDX2, Napsin A, MUC1, and MUC5. Because the chest also had lymphadenopathy, EBUS sampling was performed to check whether the lung cancer had spread. Stations 4R, 7, and 11R showed SLL, not metastatic adenocarcinoma. Right pleural effusion was also found to contain CLL/SLL by flow cytometry. The lung adenocarcinoma was therefore staged as localized T1cN0M0, Stage IA. It was removed with negative margins, and no further lung-cancer treatment was needed. Rituximab and acalabrutinib were restarted for hematologic disease control. As of January 2026, he remained lung cancer-free for 24 months. His ongoing care still required separate management of CLL/SLL-related symptoms, but the lung nodule itself had behaved as an early, surgically curable primary lung cancer rather than metastatic disease.