A transbronchial lung biopsy

A 54-year-old woman presents with a 1-year history of upper truncal obesity and moderate depression. Physical examination shows hirsutism and moon facies. Endocrinologic studies reveal hypokalemia, high plasma corticotropin levels, and increased concentrations of serum and urine cortisol. CT scan of the thorax demonstrates a hilar mass. A transbronchial lung biopsy is shown in the figure. Electron microscopy discloses neuroendocrine granules within the cytoplasm of some tumor cells. What is the appropriate diagnosis?

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  1. Adenocarcinoma
  2. Bronchioloalveolar carcinoma
  3. Carcinoid tumor
  4. Metastatic carcinoma
  5. Small cell carcinoma