A 67-year-old man complains of shortness of breath, hoarseness, productive cough, and bloody sputum of 2 weeks in duration. He admits to smoking two packs a day for 45 years and drinks occasionally. Recently, he has experienced a significant loss of appetite and weight loss. Physical examination shows pallor, cachexia, clubbing of the fingers, and barrel-shaped chest. A chest X-ray reveals a mass at the right lung apex. Histologic examination of a transbronchial biopsy is shown in the figure. What is the appropriate histologic diagnosis?
- Adenocarcinoma
- Mesothelioma
- Metastatic adenocarcinoma
- Small cell carcinoma
- Squamous cell carcinoma