PMC5376266_01
A: Computed tomography scan shows a mass in the lower lobe of the right lung, accompanied by small subpleural nodules and right pleural effusion. Fig. 1B-D: Initial biopsy specimens showing malignant cells with anisokaryosis and hyper chromatic nuclei (B, hematoxylin and eosin [H&E] staining x 200). Immunohistopathological analysis demonstrated weakly positive staining for thyroid transcription factor 1 (TTF-1) (C, x 200) and p63 (D, x 200), which suggested non-small cell lung cancer with unclear differentiation. Fig. 1E-G: Immunohistopathological analysis demonstrated negative staining for neuron specific enolase (NSE) (E, x 400), CD56 (F, x 400) and synaptophysin (G, x 400).
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The CT scan showed a mass 64 mm in diameter, located in the lower lobe of the right lung, accompanied by small sub-pleural nodules and right pleural effusion (Fig. 1A). NSCLC (Fig. 1B-D). No immunohistopathological findings of SCLC were detected in the initial dissected specimens (Fig. 1E-G). Serum tumor marker levels were carcinoembryonic antigen (CEA) 17.5 ng/mL; Sialyl-Lewis X (SLX) 68.2 U/mL; pro-gastrin-releasing peptide (pro-GRP) 299.4 pg/mL; and neuron-specific enolase (NSE) 14.2 ng/mL.
Second biopsy specimens showing malignant cells with diffuse proliferation of small-sized broken cells with scant cytoplasm and hyper chromatic nuclei (A, H&E staining x 200). Immunohistopathological analysis demonstrated positive staining for CD56 (B, x 200), synaptophysin (C, x 200), and TTF-1 (D, x 200), which suggested small cell lung cancer.
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SCLC was also identified in a biopsy from a subcutaneous tumor of the right chest, with positive immunohistochemical staining for CD56, synaptophysin and TTF-1, and negative staining for PD-L1 (Fig. 2A-D). Serum tumor markers of SCLC were elevated (NSE 117.6 ng/mL and pro-GRP 5157.5 pg/mL).