August Case of the Month

Clinical History:A 68-year-old man was found to have a suspicious left upper lobe nodule on a cancer screening chest CT (Figure 1). He was a former smoker. The patient underwent a VATS left upper lobe segmentectomy. Pathologic review demonstrated two distinct morphologies within the tumor (Figure 2). The periphery of the tumor was an adenocarcinoma with micropapillary and acinar growth patterns (Figure 3) whereas the center demonstrated a solid growth pattern composed of cords and nests of cells with moderate cytoplasm, pleomorphic nuclei with speckled chromatin and prominent nucleoli, areas of necrosis, and mitotic rate of up to 11 mitoses per 10 HPF (Figure 4). Immunohistochemical characterization of the tumor area corresponding to Figure 2 by TTF-1 (Figure 5), synaptophysin (Figure 6), and napsin A (Figure 7) is shown.

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